diff options
Diffstat (limited to '30541.txt')
| -rw-r--r-- | 30541.txt | 19721 |
1 files changed, 19721 insertions, 0 deletions
diff --git a/30541.txt b/30541.txt new file mode 100644 index 0000000..f0cdd7d --- /dev/null +++ b/30541.txt @@ -0,0 +1,19721 @@ +The Project Gutenberg EBook of A Treatise on Anatomy, Physiology, and +Hygiene (Revised Edition), by Calvin Cutter + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: A Treatise on Anatomy, Physiology, and Hygiene (Revised Edition) + +Author: Calvin Cutter + +Release Date: November 24, 2009 [EBook #30541] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK TREATISE ON ANATOMY (REVISED) *** + + + + +Produced by Bryan Ness, Dan Horwood and the Online +Distributed Proofreading Team at https://www.pgdp.net (This +file was produced from images generously made available +by The Internet Archive/American Libraries.) + + + + + + + + + + A + TREATISE + ON + ANATOMY, PHYSIOLOGY, + AND HYGIENE + + DESIGNED FOR + COLLEGES, ACADEMIES, AND FAMILIES. + + BY CALVIN CUTTER, M.D. + + ----- + WITH ONE HUNDRED AND FIFTY ENGRAVINGS. + ----- + + REVISED STEREOTYPE EDITION. + + NEW YORK: + CLARK, AUSTIN AND SMITH. + CINCINNATI:--W. B. SMITH & CO. + ST. LOUIS, MO.:--KEITH & WOODS. + + 1858. + + + + + Entered according to Act of Congress, in the year 1852, by + + CALVIN CUTTER, M. D., + + In the Clerk's Office of the District Court of the District + of Massachusetts. + + C. A. ALVORD, Printer, + No. 15 Vandewater Street, N. Y. + + + + +PREFACE. + + +Agesilaus, king of Sparta, when asked what things boys should learn, +replied, "Those which they will _practise_ when they become men." As +health requires the observance of the laws inherent to the different +organs of the human system, so not only boys, but girls, should +acquire a knowledge of the laws of their organization. If sound +morality depends upon the inculcation of correct principles in youth, +equally so does a sound physical system depend on a correct physical +education during the same period of life. If the teacher and parents +who are deficient in moral feelings and sentiments, are unfit to +communicate to children and youth those high moral principles demanded +by the nature of man, so are they equally incompetent directors of the +physical training of the youthful system, if ignorant of the organic +laws and the physiological conditions upon which health and disease +depend. + +For these reasons, the study of the structure of the human system, and +the laws of the different organs, are subjects of interest to +all,--the young and the old, the learned and the unlearned, the rich +and the poor. Every scholar, and particularly every young miss, after +acquiring a knowledge of the primary branches,--as spelling, reading, +writing, and arithmetic,--should learn the structure of the human +system, and the conditions upon which health and disease depend, as +this knowledge will be required in _practice_ in after life. + +"It is somewhat unaccountable," says Dr. Dick, "and not a little +inconsistent, that while we direct the young to look abroad over the +surface of the earth, and survey its mountains, rivers, seas, and +continents, and guide their views to the regions of the firmament, +where they may contemplate the moons of Jupiter, the rings of Saturn, +and thousands of luminaries placed at immeasurable distances, ... that +we should never teach them _to look into themselves_; to consider +their own corporeal structures, the numerous parts of which they are +composed, the admirable functions they perform, the wisdom and +goodness displayed in their mechanism, and the lessons of practical +instruction which may be derived from such contemplations." + +Again he says, "One great practical end which should always be kept in +view in the study of physiology, is the invigoration and improvement +of the corporeal powers and functions, the preservation of health, and +the prevention of disease." + +The design of the following pages is, to diffuse in the community, +especially among the youth, a knowledge of Human Anatomy, Physiology, +and Hygiene. To make the work clear and practical, the following +method has been adopted:-- + +1st. The structure of the different organs of the system has been +described in a clear and concise manner. To render this description +more intelligible, one hundred and fifty engravings have been +introduced, to show the situation of the various organs. Hence the +work may be regarded as an elementary treatise on anatomy. + +2d. The functions, or uses of the several parts have been briefly and +plainly detailed; making a primary treatise on human physiology. + +3d. To make a knowledge of the structure and functions of the +different organs _practical_, the laws of the several parts, and the +conditions on which health depends, have been clearly and succinctly +explained. Hence it may be called a treatise on the principles of +hygiene, or health. + +To render this department more complete, there has been added the +appropriate treatment for burns, wounds, hemorrhage from divided +arteries, the management of persons asphyxiated from drowning, +carbonic acid, or strangling, directions for nurses, watchers, and the +removal of disease, together with an Appendix, containing antidotes +for poisons, so that persons may know what _should be done_, and what +_should not be done_, until a surgeon or physician can be called. + +In attempting to effect this in a brief elementary treatise designed +for schools and families, it has not been deemed necessary to use +vulgar phrases for the purpose of being understood. The appropriate +scientific term should be applied to each organ. No more effort is +required to learn the meaning of a _proper_, than an improper term. +For example: a child will pronounce the word as readily, and obtain as +correct an idea, if you say _lungs_, as if you used the word _lights_. +A little effort on the part of teachers and parents, would diminish +the number of vulgar terms and phrases, and, consequently, improve the +language of our country. To obviate all objections to the use of +proper scientific terms, a Glossary has been appended to the work. + +The author makes no pretensions to new discoveries in physiological +science. In preparing the anatomical department, the able treatises of +Wilson, Cruveilhier, and others have been freely consulted. In the +physiological part, the splendid works of Carpenter, Dunglison, +Liebig, and others have been perused. In the department of hygiene +many valuable hints have been obtained from the meritorious works of +Combe, Rivers, and others. + +We are under obligations to R. D. Mussey, M. D., formerly Professor of +Anatomy and Surgery, Dartmouth College, N. H., now Professor of +Surgery in the Ohio Medical College; to J. E. M'Girr, A. M., M. D., +Professor of Anatomy, Physiology, and Chemistry, St. Mary's +University, Ill.; to E. Hitchcock, Jr., A. M., M. D., Teacher of +Chemistry and Natural History, Williston Seminary, Mass.; to Rev. E. +Hitchcock, D. D., President of Amherst College, Mass., who examined +the revised edition of this work, and whose valuable suggestions +rendered important aid in preparing the manuscript for the present +stereotype edition. + +We return our acknowledgments for the aid afforded by the Principals +of the several Academies and Normal Schools who formed classes in +their institutions, and examined the revised edition as their pupils +progressed, thus giving the work the best possible test trial, namely, +the recitation-room. + +To the examination of an intelligent public, the work is respectfully +submitted by + + CALVIN CUTTER. + +WARREN, MASS., _Sept. 1, 1852_. + + + + +TO TEACHERS AND PARENTS. + + +As the work is divided into chapters, the subjects of which are +complete in themselves, the pupil may commence the study of the +structure, use, and laws of the several parts of which the human +system is composed, by selecting such chapters as fancy or utility may +dictate, without reference to their present arrangement,--as well +commence with the chapter on the digestive organs as on the bones. + +The acquisition of a correct pronunciation of the technical words is +of great importance, both in recitation and in conversation. In this +work, the technical words interspersed with the text, have been +divided into syllables, and the accented syllables designated. An +ample Glossary of technical terms has also been appended to the work, +to which reference should be made. + +It is recommended that the subject be examined in the form of +_topics_. The questions in _Italics_ are designed for this method of +recitation. The teacher may call on a pupil of the class to describe +the anatomy of an organ from an anatomical outline plate; afterwards +call upon another to give the physiology of the part, while a third +may state the hygiene, after which, the questions at the bottom of +the page may be asked promiscuously, and thus the detailed knowledge +of the subject possessed by the pupils will be tested. + +At the close of the chapters upon the Hygiene of the several portions +of the system, it is advised that the instructor give a lecture +reviewing the anatomy, physiology, and hygiene, of the topic last +considered. This may be followed by a general examination of the class +upon the same subject. By this course a clear and definite knowledge +of the mutual relation of the Anatomy, Physiology, and Hygiene, of +different parts of the human body, will be presented. + +We also suggest the utility of the pupils' giving analogous +illustrations, examples, and observations, where these are interspersed +in the different chapters, not only to induce inventive thought, but to +discipline the mind. + +To parents and others we beg leave to say, that about two thirds of +the present work is devoted to a concise and practical description of +the uses of the important organs of the human body, and to show how +such information may be usefully applied, both in the preservation of +health, and the improvement of physical education. To this have been +added directions for the treatment of those accidents which are daily +occurring in the community, making it a treatise proper and profitable +for the FAMILY LIBRARY, as well as the school-room. + + + + +CONTENTS. + + + Chapter. Page. + 1. General Remarks, 13 + 2. Structure of Man, 17 + 3. Chemistry of the Human Body, 25 + 4. Anatomy of the Bones, 29 + 5. Anatomy of the Bones, continued, 39 + 6. Physiology of the Bones, 48 + 7. Hygiene of the Bones, 53 + 8. Anatomy of the Muscles, 64 + 9. Physiology of the muscles, 76 + 10. Hygiene of the Muscles, 85 + 11. Hygiene of the Muscles, continued, 96 + 12. Anatomy of the Teeth, 105 + 12. Physiology of the Teeth, 109 + 12. Hygiene of the Teeth, 110 + 13. Anatomy of the Digestive Organs, 113 + 14. Physiology of the Digestive Organs, 124 + 15. Hygiene of the Digestive Organs, 129 + 16. Hygiene of the Digestive Organs, continued, 142 + 17. Anatomy of the Circulatory Organs, 154 + 18. Physiology of the Circulatory Organs, 164 + 19. Hygiene of the Circulatory Organs, 172 + 20. Anatomy of the Lymphatic Vessels, 181 + 20. Physiology of the Lymphatic Vessels, 183 + 20. Hygiene of the Lymphatic Vessels, 188 + 21. Anatomy of the Secretory Organs. 192 + 21. Physiology of the Secretory Organs, 193 + 21. Hygiene of the Secretory Organs, 197 + 22. Nutrition, 200 + 22. Hygiene of Nutrition, 205 + 23. Anatomy of the Respiratory Organs, 209 + 24. Physiology of the Respiratory Organs, 217 + 25. Hygiene of the Respiratory Organs, 228 + 26. Hygiene of the Respiratory Organs, continued, 239 + 27. Animal Heat, 252 + 28. Hygiene of Animal Heat, 261 + 29. Anatomy of the Vocal Organs, 268 + 29. Physiology of the Vocal Organs, 272 + 30. Hygiene of the Vocal Organs, 274 + 31. Anatomy of the Skin, 282 + 32. Physiology of the Skin, 293 + 33. Hygiene of the Skin, 301 + 34. Hygiene of the Skin, continued, 311 + 35. Appendages of the Skin, 322 + 36. Anatomy of the Nervous System, 327 + 37. Anatomy of the Nervous System, continued, 340 + 38. Physiology of the Nervous System, 346 + 39. Hygiene of the Nervous System, 358 + 40. Hygiene of the Nervous System, continued, 368 + 41. The Sense of Touch, 378 + 42. Anatomy of the Organs of Taste, 384 + 42. Physiology of the Organs of Taste, 386 + 43. Anatomy of the Organs of Smell, 389 + 43. Physiology of the Organs of Smell, 391 + 44. Anatomy of the Organs of Vision, 394 + 45. Physiology of the Organs of Vision, 404 + 45. Hygiene of the Organs of Vision, 410 + 46. Anatomy of the Organs of Hearing, 414 + 47. Physiology of the Organs of Hearing, 420 + 47. Hygiene of the Organs of Hearing, 422 + 48. Means of preserving the Health, 425 + 49. Directions for Nurses, 432 + - - - - - + APPENDIX, 439 + GLOSSARY, 451 + INDEX, 463 + + + + +ANATOMY, &c. + +CHAPTER I. + +GENERAL REMARKS. + + +1. ANATOMY is the science which treats of the structure and relations +of the different parts of animals and plants. + +2. It is divided into _Vegetable_ and _Animal_ anatomy. The latter of +these divisions is subdivided into _Human_ anatomy, which considers, +exclusively, human beings; and _Comparative_ anatomy, which treats of +the mechanism of the lower orders of animals. + +3. PHYSIOLOGY treats of the functions, or uses of the organs of +animals and plants. Another definition is, "the science of life." + +4. This is also divided into _Vegetable_ and _Animal_ physiology, as +it treats of the vegetable or animal kingdom; and into _Human_ and +_Comparative_ physiology, as it describes the vital functions of man +or the inferior animals. + +5. HYGIENE is the art or science of maintaining health, or a knowledge +of those laws by which health may be preserved. + +6. The kingdom of nature is divided into _organic_ and _inorganic_ +bodies. Organic bodies possess organs, on whose action depend their +growth and perfection. This division includes animals and plants. +Inorganic bodies are devoid of organs, or instruments of life. In this +division are classed the earths, metals, and other minerals. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1. What is anatomy? 2. How is it divided? How is the latter division +subdivided? 3. What is physiology? Give another definition. 4. How is +physiology divided? Give a subdivision. 5. What is hygiene? 6. Define +organic bodies. + + -=-=-=-=-=-=-=-=-=-=-=-= + +7. In general, organic matter differs so materially from inorganic, +that the one can readily be distinguished from the other. In the +organic world, every individual of necessity springs from some +_parent, or immediate producing agent_; for while inorganic substances +are formed by chemical laws alone, we see no case of an animal or +plant coming into existence by accident or chance, or chemical +operations. + +8. Animals and plants _are supported by means of nourishment_, and die +without it. They also increase in size _by the addition of new +particles of matter to all parts of their substances_; while rocks and +minerals grow only by additions to their surfaces. + +9. "Organized bodies always present a combination of both solids and +fluids;--of solids, differing in character and properties, arranged +into organs, and these endowed with functional powers, and so +associated as to form of the whole a single system;--and of fluids, +contained in these organs, and holding such relation to the solids +that the existence, nature, and properties of both mutually and +necessarily depend on each other." + +10. Another characteristic is, that organic substances have a _certain +order of parts_. For example, plants possess organs to gain +nourishment from the soil and atmosphere, and the power to give +strength and increase to all their parts. And animals need not only a +digesting and circulating apparatus, but organs for breathing, a +nervous system, &c. + + -=-=-=-=-=-=-=-=-=-=-=-= + +6. Define inorganic bodies. 7. What is said of the difference, in +general, between organic and inorganic bodies? 8. What of the growth +of organic and inorganic bodies? 9. What do organized bodies always +present? 10. Give another characteristic of organized substances. + + -=-=-=-=-=-=-=-=-=-=-=-= + +11. _Individuality_ is an important characteristic. For instance, a +large rock may be broken into a number of smaller pieces, and yet +every fragment will be rock; but if an organic substance be separated +into two or more divisions, neither of them can be considered an +individual. Closely associated with this is the power of _life_, or +_vitality_, which is the most distinguishing characteristic of organic +structure; since we find nothing similar to this in the inorganic +creation. + +12. _The distinction between plants and animals_ is also of much +importance. _Animals grow proportionally in all directions_, while +plants grow upwards and downwards from a collet only. The _food_ of +animals is _organic_, while that of plants is _inorganic_; the latter +feeding entirely upon the elements of the soil and atmosphere, while +the former subsist upon the products of the animal and vegetable +kingdoms. The size of the vegetable is in most cases limited only by +the duration of existence, as a tree continues to put forth new +branches during each period of its life, while the animal, at a +certain time of life, attains the average size of its species. + +13. One of the most important distinctions between animals and plants, +is _the different effects of respiration_. Animals consume the oxygen +of the atmosphere, and give off carbonic acid; while plants take up +the carbonic acid, and restore to animals the oxygen, thus affording +an admirable example of the principle of compensation in nature. + +14. But the decisive distinctions between animals and plants are +_sensation_ and _voluntary motion_, the power of acquiring a knowledge +of external objects through the senses, and the ability to move from +place to place at will. These are the characteristics which, in their +fullest development in man, show intellect and reasoning powers, and +thereby in a greater degree exhibit to us the wisdom and goodness of +the Creator. + + -=-=-=-=-=-=-=-=-=-=-=-= + +11. What is said of the individuality of organized and inorganized +bodies? What is closely associated with this? 12. Give a distinction +between animals and plants as regards growth. The food of animals and +plants. What is said in respect to size? 13. What important +distinction in the effects of respiration of animals and plants? 14. +What are the decisive distinctions between animals and plants? + + -=-=-=-=-=-=-=-=-=-=-=-= + +15. DISEASE, which consists in an unnatural condition of the bodily +organs, is in most cases under the control of fixed laws, which we are +capable of understanding and obeying. Nor do diseases come by chance; +they are penalties for violating physical laws. If we carelessly cut +or bruise our flesh, pain and soreness follow, to induce us to be more +careful in the future; or, if we take improper food into the stomach, +we are warned, perhaps immediately by a friendly pain, that we have +violated an organic law. + +16. Sometimes, however, the penalty does not directly follow the sin, +and it requires great physiological knowledge to be able to trace the +effect to its true cause. If we possess good constitutions, we are +responsible for most of our sickness; and bad constitutions, or +hereditary diseases, are but the results of the same great law,--the +iniquities of the parents being visited on the children. In this view +of the subject, how important is the study of physiology and hygiene! +For how can we expect to obey laws which we do not understand? + + -=-=-=-=-=-=-=-=-=-=-=-= + +15. What is said of disease? 16. Why is the study of physiology and +hygiene important? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER II. + +STRUCTURE OF MAN, + + +17. In the structure of the human body, there is a union of fluids and +solids. These are essentially the same, for the one is readily changed +into the other. There is no fluid that does not contain solid matter +in solution, and no solid matter that is destitute of fluid. + +18. In different individuals, and at different periods of life the +proportion of fluids and solids varies. In youth, the fluids are more +abundant than in advanced life. For this reason, the limbs in +childhood are soft and round, while in old age they assume a hard and +wrinkled appearance. + +19. The fluids not only contain the materials from which every part of +the body is formed, but they are the medium for conveying the waste, +decayed particles of matter from the system. They have various names, +according to their nature and function; as, the blood, and the bile. + +20. The solids are formed from the fluids, and consequently they are +reduced, by chemical analysis, to the same ultimate elements. The +particles of matter in solids are arranged variously; sometimes in +_fi'bres_, (threads,) sometimes in _lam'i-nae_, (plates,) sometimes +homogeneously, as in basement membranes. (Appendix A.) + +21. The parts of the body are arranged into _Fi'bres_, _Fas-cic'u-li_, +_Tis'sues_, _Or'gans_, _Ap-pa-ra'tus-es_, and _Sys'tems_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +17. What substances enter into the structure of the human body? Are +they essentially the same? 18. What is said of these substances at +different periods of life? 19. What offices do the fluids of the +system perform? 20. What is said of the solids? How are the particles +of matter arranged in solids? 21. Give an arrangement of the parts of +the body. + + -=-=-=-=-=-=-=-=-=-=-=-= + +22. A FIBRE is a thread of exceeding fineness. It is either +cylindriform or flattened. + +23. A FASCICULUS is the term applied to several fibres united. Its +general characteristics are the same as fibres. + +24. A TISSUE is a term applied to several different solids of the +body. + +25. An ORGAN is composed of tissues so arranged as to form an +instrument designed for action. The action of an organ is called its +_function_, or use. + +_Example._ The liver is an organ, and the secretion of the bile from +the blood is one of its functions.[1] + + [1] Where examples and observations are given or experiments + suggested, let the pupil mention other analogous ones. + +26. An APPARATUS is an assemblage of organs designed to produce +certain results. + +_Example._ The digestive apparatus consists of the teeth, stomach, +liver, &c., all of which aid in the digestion of food. + +[Illustration: Fig. 2. Represents a portion of broken muscular fibre of +animal life, (magnified about seven hundred diameters.)] + +27. The term SYSTEM is applied to an assemblage of organs arranged +according to some plan, or method; as the nervous system, the +respiratory system. + + -=-=-=-=-=-=-=-=-=-=-=-= + +22. Define a fibre. 23. Define a fasciculus. 24. Define a tissue. 25. +Define an organ. What is the action of an organ called? Give examples. +_Mention other examples._ 26. What is an apparatus? Give an example +27. How is the term system applied? + + -=-=-=-=-=-=-=-=-=-=-=-= + +28. A TISSUE is a simple form of organized animal substance. It is +flexible, and formed of fibres interwoven in various ways; as, the +cellular tissue. + +29. However various all organs may appear in their structure and +composition, it is now supposed that they can be reduced to a few +tissues; as, the _Cel'lu-lar_, _Os'se-ous_, _Mus'cu-lar_, _Mu'cous_, +_Ner'vous_, &c. (Appendix B.) + +30. The CELLULAR TISSUE,[2] now called the _areolar tissue_, consists +of small fibres, or bands, interlaced in every direction, so as to +form a net-work, with numerous interstices that communicate freely +with each other. These interstices are filled, during life, with a +fluid resembling the serum of blood. The use of the areolar tissue is +to connect together organs and parts of organs, and to envelop, fix, +and protect the vessels and nerves of organs. + + [2] The _Cellular_, _Serous_, _Dermoid_, _Fibrous_, and _Mucous + tissues_ are very generally called _membranes_. + +[Illustration: Fig. 3. Arrangement of fibres of the cellular tissue +magnified one hundred and thirty diameters.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +28. What is a tissue? 29. What is said respecting the structure and +composition of the various organs? Name the primary membranes. 30. +Describe the cellular tissue. How are the cells imbedded in certain +tissues? Give observation 1st, relative to the cellular tissue. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observations._ 1st. When this fluid becomes too great in quantity, in +consequence of disease, the patient labors under general dropsy. The +swelling of the feet when standing, and their return to a proper shape +during the night, so often noticed in feeble persons, furnish a +striking proof both of the existence and peculiarity of this tissue, +which allows the fluid to flow from cell to cell, until it settles in +the lower extremities. + +2d. The free communication between the cells is still more remarkable +in regard to air. Sometimes, when an accidental opening has been made +from the air-cells of the lungs into the contiguous cellular tissue, +the air in respiration has penetrated every part until the whole body +is so inflated as to occasion suffocation. Butchers often avail +themselves of the knowledge of this fact, and inflate their meat to +give it a fat appearance. + +31. "Although this tissue enters into the composition of all organs, +it never loses its own structure, nor participates in the functions of +the organ of which it forms a part. Though present in the nerves, it +does not share in their sensibility; and though it accompanies every +muscle and every muscular fibre, it does not partake of the +irritability which belongs to these organs." + +32. Several varieties of tissue are formed from the cellular; as, the +_Se'rous_, _Der'moid_, _Fi'brous_, and several others. + +33. The SEROUS TISSUE lines all the closed, or sac-like cavities of +the body; as, the chest, joints, and abdomen. It not only lines these +cavities, but is reflected, and invests the organs contained in them. +The liver and the lungs are thus invested. This membrane is of a +whitish color, and smooth on its free surfaces. These surfaces are +kept moist, and prevented from adhering by a _se'rous_ fluid, which is +separated from the blood. The use of this membrane is to separate +organs and also to facilitate the movement of one part upon another, +by means of its moist, polished surfaces. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give observation 2d. 31. What is said of the identity of this tissue? +32. Name the varieties of tissue formed from the cellular. 33. Where +is the serous tissue found? What two offices does it perform? Give its +structure. What is the use of this membrane? + + -=-=-=-=-=-=-=-=-=-=-=-= + +34. The DERMOID TISSUE covers the outside of the body. It is called +the _cu'tis_, (skin.) This membrane is continuous with the mucous at +the various orifices of the body, and in these situations, from the +similarity of their structure, it is difficult to distinguish between +them. + +_Observations._ 1st. In consequence of the continuity and similarity +of structure, there is close sympathy between the mucous and dermoid +membranes. If the functions of the skin are disturbed, as by a chill, +it will frequently cause a catarrh, (cold,) or diarrhoea. Again, in +consequence of this intimate sympathy, these complaints can be +relieved by exciting a free action in the vessels of the skin. + +2d. It is no uncommon occurrence that diseased or irritated conditions +of the mucous membrane of the stomach or intestines produce diseases +or irritations of the skin, as is seen in the rashes attendant on +dyspepsia, and eating certain species of fish. These eruptions of the +skin can be relieved by removing the diseased condition of the +stomach. + +35. The FIBROUS TISSUE consists of longitudinal, parallel fibres, +which are closely united. These fibres, in some situations, form a +thin, dense, strong membrane, like that which lines the internal +surface of the skull, or invests the external surface of the bones. +In other instances, they form strong, inelastic bands, called +_lig'a-ments_, which bind one bone to another. This tissue also +forms _ten'dons_, (white cords,) by which the muscles are attached +to the bones. + +_Observation._ In the disease called rheumatism, the fibrous tissue is +the part principally affected; hence the joints, where this tissue is +most abundant, suffer most from this affection. + + -=-=-=-=-=-=-=-=-=-=-=-= + +34. Describe the dermoid tissue. What is said of the sympathy between +the functions of the skin and mucous membrane? Give another instance +of the sympathy between these membranes. 35. Of what does the fibrous +tissue consist? How do these appear in some situations? How in others? +What tissue is generally affected in rheumatism? + + -=-=-=-=-=-=-=-=-=-=-=-= + +36. The ADIPOSE TISSUE is so arranged as to form distinct bags, or +cells. These contain a substance called _fat_. This tissue is +principally found beneath the skin, abdominal muscles, and around the +heart and kidneys; while none is found in the brain, eye, ear, nose, +and several other organs. + +_Observation._ In those individuals who are corpulent, there is in +many instances, a great deposit of this substance. This tissue +accumulates more readily than others when a person becomes gross, and +is earliest removed when the system emaciates, in acute or chronic +diseases. Some of the masses become, in some instances, enlarged. +These enlargements are called _adipose_, or _fatty tumors_. + +[Illustration: Fig. 4. 1, A portion of the adipose tissue. 2, 2, 2, +Minute bags containing fat. 3, A cluster of these bags, separated and +suspended.] + +37. The CARTILAGINOUS TISSUE is firm, smooth, and highly elastic. +Except bone, it is the hardest part of the animal frame. It tips the +ends of the bones that concur in forming a joint. Its use is to +facilitate the motion of the joints by its smooth surface, while its +elastic character diminishes the shock that would otherwise be +experienced if this tissue were inelastic. + + -=-=-=-=-=-=-=-=-=-=-=-= + +36. Describe the adipose tissue. Where does this tissue principally +exist? Give observation in regard to the adipose tissue. 37. Describe +the cartilaginous tissue. What is its use? + + -=-=-=-=-=-=-=-=-=-=-=-= + +38 The OSSEOUS TISSUE, in composition and arrangement of matter, +varies at different periods of life, and in different bones. In some +instances, the bony matter is disposed in plates, while in other +instances, the arrangement is cylindrical. Sometimes, the bony matter +is dense and compact; again, it is spongy, or porous. In the centre of +the long bones, a space is left which is filled with a fatty +substance, called _mar'row_. + +_Observation._ Various opinions exist among physiologists in regard to +the use of marrow. Some suppose it serves as a reservoir of +nourishment, while others, that it keeps the bones from becoming dry +and brittle. The latter opinion, however, has been called in question, +as the bones of the aged man contain more marrow than those of the +child, and they are likewise more brittle. + +[Illustration: Fig. 5. A section of the femur, (thigh-bone.) 1, 1, The +extremities, showing a thin plate of compact texture, which covers small +cells, that diminish in size, but increase in number, as they approach +the articulation. 2, 2, The walls of the shaft, which are very firm and +solid. 3, The cavity that contains the marrow.] + +39. The MUSCULAR TISSUE is composed of many fibres, that unite to form +fasciculi, each of which is enclosed in a delicate layer of cellular +tissue. Bundles of these fasciculi constitute a muscle. + +_Observation._ A piece of boiled beef will clearly illustrate the +arrangement of muscular fibre. + + -=-=-=-=-=-=-=-=-=-=-=-= + +38. What is said of the osseous tissue? How is the bony matter +arranged in different parts of the animal frame? What is said of the +use of marrow? 39. Of what is the muscular tissue composed? How may +the arrangement of muscular fibre be illustrated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +40. The MUCOUS TISSUE differs from the serous by its lining all +the cavities which communicate with the air. The nostrils, the +mouth, and the stomach afford examples. The external surface of this +membrane, or that which is exposed to the air, is soft, and bears some +resemblance to the downy rind of a peach. It is covered by a viscid +fluid called _mu'cus_. This is secreted by small _gland-cells_, +called _ep-i-the'li-a_, or secretory cells of the mucous membrane. +The use of this membrane and its secreted mucus is to protect the +inner surface of the cavities which it lines. + +_Observation._ A remarkable sympathy exists between the remote parts +of the mucous membrane. Thus the condition of the stomach may be +ascertained by an examination of the tongue. + +41. The NERVOUS TISSUE consists of soft, pulpy matter, enclosed in +a sheath, called _neu-ri-lem'a_. This tissue consists of two +substances. The one, of a pulpy character and gray color, is called +_cin-e-ri'tious_, (ash-colored.) The other, of a fibrous character and +white, is named _med'ul-la-ry_, (marrow-like.) In every part of the +nervous system both substances are united, with the exception of the +nervous fibres and filaments, which are solely composed of the +medullary matter enclosed in a delicate sheath. + + -=-=-=-=-=-=-=-=-=-=-=-= + +40. How does the mucous differ from the serous tissue? What is the +appearance of the external surface of this membrane? Where is the +mucus secreted? What is the use of this membrane? 41. Of what does the +nervous tissue consist? Describe the two substances that enter into +the composition of the nervous tissue. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER III + +CHEMISTRY OF THE HUMAN BODY. + + +42. An ULTIMATE ELEMENT is the simplest form of matter with which we +are acquainted; as gold, iron, &c. + +43. These elements are divided into _metallic_ and _non-metallic_ +substances. The metallic substances are _Po-tas'si-um_, _So'di-um_, +_Cal'ci-um_, _Mag-ne'si-um_, _A-lu'min-um_, _I'ron_, _Man'ga-nese_, and +_Cop'per_. The non-metallic substances are _Ox'y-gen_, _Hy'dro-gen_, +_Car'bon_, _Ni'tro-gen_, _Si-li'-ci-um_, _Phos'phor-us_, _Sul'phur_, +_Chlo'rine_, and a few others. + +44. POTASH (potassium united with oxygen) is found in the blood, bile, +perspiration, milk, &c. + +45. SODA (sodium combined with oxygen) exists in the muscles, and in +the same fluids in which potash is found. + +46. LIME (calcium combined with oxygen) forms the principal ingredient +of the bones. The lime in them is combined with phosphoric and +carbonic acid. + +47. MAGNESIA (magnesium combined with oxygen) exists in the bones, +brain, and in some of the animal fluids; as milk. + +48. SILEX (silicium combined with oxygen) is contained in the hair and +in some of the secretions. + +49. IRON forms the coloring principle of the red globules of the +blood, and is found in every part of the system. + +_Observation._ As metallic or mineral substances enter into the +ultimate elements of the body, the assertion that all minerals are +poisonous, however small the quantity, is untrue. + + -=-=-=-=-=-=-=-=-=-=-=-= + +42. What is an ultimate element? Give examples. 43. How are they +divided? Name the metallic substances. Name the non-metallic +substances. 44. What is said of potash? 45. Of soda? 46. Of lime? 47. +Of magnesia? 48. Of silex? 49. What forms the coloring principle of +the blood? What is said of mineral substances? + + -=-=-=-=-=-=-=-=-=-=-=-= + +50. OXYGEN is contained in all the fluids and solids of the body. It +is almost entirely derived from the inspired air and water. It is +expelled in the form of carbonic acid and water from the lungs and +skin. It is likewise removed in the other secretions. + +51. HYDROGEN is found in all the fluids and in all the solids of +the body. It is derived from the food, as well as from water and +other drinks. It exists in the greatest abundance in the impure, +dark-colored blood of the system. It is removed by the agency of the +kidneys, skin, lungs, and other excretory organs. + +52. CARBON is an element in the oil, fat, albumen, fibrin, gelatin, +bile, and mucus. This element likewise exists in the impure blood in +the form of carbonic acid gas. Carbon is obtained from the food, and +discharged from the system by the secretions and respiration. + +53. NITROGEN is contained in most animal matter, but is most abundant +in fibrin. It is not contained in fat and a few other substances. + +_Observation._ The peculiar smell of animal matter when burning is +owing to nitrogen. This element combined with hydrogen forms +_am-mo'ni-a_, (hartshorn,) when animal matter is in a state of +putrefaction. + +54. PHOSPHORUS is contained in many parts of the system, but more +particularly in the bones. It is generally found in combination with +oxygen, forming _phosphoric acid_. The phosphoric acid is usually +combined with alkaline bases; as lime in the bones, forming phosphate +of lime. + +55. SULPHUR exists in the bones, muscles, hair, and nails. It is +expelled from the system by the skin and intestines. + +56. CHLORINE is found in the blood, gastric juice, milk, perspiration, +and saliva. + + -=-=-=-=-=-=-=-=-=-=-=-= + +50. What is said of oxygen? 51. Of hydrogen? 52. What is said of +carbon? 53. Of nitrogen? How is ammonia formed? 54. What is said of +phosphorus? 55. What is said of sulphur? 56. Of chlorine? + + -=-=-=-=-=-=-=-=-=-=-=-= + +57. PROXIMATE ELEMENTS are forms of matter that exist in organized +bodies in abundance, and are composed chiefly of oxygen, hydrogen, +carbon, and nitrogen, arranged in different proportions. They exist +already formed, and may be separated in many instances, by heat or +mechanical means. The most important compounds are _Al-bu'men_, +_Fi'brin_, _Gel'a-tin_, _Mu'cus_, _Fat_, _Ca'se-ine_, _Chon'drine_, +_Lac'tic acid_, and _Os'ma-zome_. + +58. ALBUMEN is found in the body, both in a fluid and solid form. It +is an element of the skin, glands, hair, and nails, and forms the +principal ingredient of the brain. Albumen is without color, taste, or +smell, and it coagulates by heat, acids, and alcohol. + +_Observation._ The white of an egg is composed of albumen, which can +be coagulated or hardened by alcohol. As albumen enters so largely +into the composition of the brain, is not the impaired intellect and +moral degradation of the inebriate attributable to the effect of +alcohol in hardening the albumen of this organ? + +59. FIBRIN exists abundantly in the blood, chyle, and lymph. It +constitutes the basis of the muscles. Fibrin is of a whitish color, +inodorous, and insoluble in cold water. It differs from albumen by +possessing the property of coagulating at all temperatures. + +_Observation._ Fibrin may be obtained by washing the thick part of +blood with cold water; by this process, the red globules, or coloring +matter, are separated from this element. + +60. GELATIN is found in nearly all the solids, but it is not known to +exist in any of the fluids. It forms the basis of the cellular tissue, +and exists largely in the skin, bones, ligaments, and cartilages. + + -=-=-=-=-=-=-=-=-=-=-=-= + +57. What are proximate elements? Do they exist already formed in +organized bodies? Name the most important compounds. 58. What is said +of albumen? Give observation relative to this element. 59. Of fibrin? +How does albumen differ from fibrin? How can fibrin be obtained? 60. +What is said of gelatin? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Gelatin is known from other organic principles by its +dissolving in warm water, and forming "jelly." When dry, it forms the +hard, brittle substance, called _glue_. Isinglass, which is used in +the various mechanical arts, is obtained from the sounds of the +sturgeon. + +61. MUCUS is a viscid fluid secreted by the gland-cells, or epithelia. +Various substances are included under the name of mucus. It is +generally alkaline, but its true chemical character is imperfectly +understood. It serves to moisten and defend the mucous membrane. It is +found in the cuticle, brain, and nails; and is scarcely soluble in +water, especially when dry. (Appendix C.) + +62. OSMAZOME is a substance of an aromatic flavor. It is of a +yellowish-brown color, and is soluble both in water and alcohol, but +does not form a jelly by concentration. It is found in all the fluids, +and in some of the solids; as the brain. + +_Observation._ The characteristic odor and taste of soup are owing to +osmazome. + +63. There are several acids found in the human system; as the +_A-ce'tic_, _Ben-zo'ic_, _Ox-al'ic_, _U'ric_, and some other +substances, but not of sufficient importance to require a particular +description. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is it known from other organic principles? 61. What is said of +mucus? 62. Of osmazome? To what are the taste and odor of soup owing? +63. What acids are found in the system? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER IV. + +THE BONES. + + +64. The bones are firm and hard, and of a dull white color. In all the +higher orders of animals, among which is man, they are in the interior +of the body, while in lobsters, crabs, &c., they are on the outside, +forming a case which protects the more delicate parts from injury. + +65. In the mechanism of man, the variety of movements he is called to +perform requires a correspondent variety of component parts, and the +different bones of the system are so admirably adapted to each other, +that they admit of numerous and varied motions. + +66. When the bones composing the skeleton are united by natural +ligaments, they form what is called a _natural skeleton_, when united +by wires, what is termed an _artificial skeleton_. + +67. The elevations, or protuberances, of the bones are called +_proc'es-ses_, and are, generally, the points of attachment for the +muscles and ligaments. + + +ANATOMY OF THE BONES. + +68. The BONES are composed of both animal and earthy matter. The +earthy portion of the bones gives them solidity and strength, while +the animal part endows them with vitality. + + -=-=-=-=-=-=-=-=-=-=-=-= + +64. What is said of the bones? 65. Is there an adaptation of the bones +of the system to the offices they are required to perform? 66. What is +a natural skeleton? What an artificial? 67. What part of the bones are +called processes? 68-73. _Give the structure of the bones._ 68. Of +what are the bones composed? What are the different uses of the +component parts of the bones? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Experiments._ 1st. To show the earthy without the animal matter, burn +a bone in a clear fire for about fifteen minutes, and it becomes white +and brittle, because the gelatin, or animal matter of the bone, has +been destroyed. + +2d. To show the animal without the earthy matter of the bones, immerse +a slender bone for a few days in a weak acid, (one part muriatic acid +and six parts water,) and it can then be bent in any direction. In +this experiment, the acid has removed the earthy matter, (carbonate +and phosphate of lime,) yet the form of the bone is unchanged. + +69. The bones are formed from the blood, and are subjected to several +changes before they are perfected. At their early formative stage, +they are cartilaginous. The vessels of the cartilage, at this period, +convey only the _lymph_, or white portion of the blood; subsequently, +they convey red blood. At this time, true ossification (the deposition +of phosphate and carbonate of lime) commences at certain points, which +are called _the points of ossification_. + +70. Most of the bones are formed of several pieces, or centres of +ossification. This is seen in the long bones which have their +extremities separated from the body by a thin partition of cartilage. +It is some time before these separate pieces are united to form one +bone. + +71. When the process of ossification is completed, there is still a +constant change in the bones. They increase in bulk, and become less +vascular, until middle age. In advanced life, the elevations upon +their surface and near the extremities become more prominent, +particularly in individuals accustomed to labor. As a person advances +in years, the vitality diminishes, and in extreme old age, the earthy +substance predominates; consequently, the bones are extremely +brittle. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How can the earthy matter of the bones be shown? The animal? 69. +What is the appearance of the bones in their early formative stage? +When does true ossification commence? 70. How are most of the bones +formed? 71. What is said of the various changes of the bones after +ossification? + + -=-=-=-=-=-=-=-=-=-=-=-= + +72. The fibrous membrane that invests the bones is called +_per-i-os'te-um_; that which covers the cartilages is called +_per-i-chon'dri-um_. When this membrane invests the skull, it is +called _per-i-cra'ni-um_. + +[Illustration: Fig. 6. A section of the knee-joint. The lower part of the +femur, (thigh-bone,) and upper part of the tibia, (leg-bone,) are seen +ossified at 1, 1. The cartilaginous extremities of the two bones are seen +at _d_, _d_. The points of ossification of the extremities, are seen at +2, 2. The patella, or knee-pan, is seen at _c_. 3, A point, or centre of +ossification.] + +73. The PERIOSTEUM is a firm membrane immediately investing the bones, +except where they are tipped with cartilage, and the crowns of the +teeth, which are protected by enamel. This membrane has minute nerves, +and when healthy, possesses but little sensibility. It is the +nutrient membrane of the bone, endowing its exterior with vitality; it +also gives insertion to the tendons and connecting ligaments of the +joints. + + -=-=-=-=-=-=-=-=-=-=-=-= + +72. What is the membrane called that invests the bones? That covers +the cartilage? That invests the skull? Explain fig. 6. 73. Describe +the periosteum. + + -=-=-=-=-=-=-=-=-=-=-=-= + +74. There are two hundred and eight[3] bones in the human body, +beside the teeth. These, for convenience, are divided into four +parts: 1st. The bones of the _Head_. 2d. The bones of the _Trunk_. +3d. The bones of the _Upper Extremities_. 4th. The bones of the +_Lower Extremities_. + + [3] Some anatomists reckon more than this number, others less, for + the reason that, at different periods of life, the number of + pieces of which one bone is formed, varies. _Example._ The + breast-bone, in infancy, has _eight_ pieces; in youth, _three_; + in old age, but _one_. + +75. The bones of the HEAD are divided into those of the _Skull_, +_Ear_, and _Face_. + +76. The SKULL is composed of eight bones. They are formed of two +plates, or tablets of bony matter, united by a porous portion of bone. +The external tablet is fibrous and tough; the internal plate is dense +and hard, and is called the _vit're-ous_, or glassy table. These +tough, hard plates are adapted to resist the penetration of sharp +instruments, while the different degrees of density possessed by the +two tablets, and the intervening spongy bone, serve to diminish the +vibrations that would occur in falls or blows. + +77. The skull is convex externally, and at the base much thicker than +at the top or sides. The most important part of the brain is placed +here, completely out of the way of injury, unless of a very serious +nature. The base of the cranium, or skull, has many projections, +depressions, and apertures; the latter affording passages for the +nerves and blood-vessels. + + -=-=-=-=-=-=-=-=-=-=-=-= + +74. How many bones in the human body? How are they divided? 75-81. +_Give the anatomy of the bones of the head._ 75. How are the bones of +the head divided? 76. Describe the bones of the skull. 77. What is the +form of the skull? What does the base of the skull present? + + -=-=-=-=-=-=-=-=-=-=-=-= + +78. The bones of the cranium are united by ragged edges, called +_sut'ures_. The edges of each bone interlock with each other, +producing a union, styled, in carpentry, _dovetailing_. They +interrupt, in a measure, the vibrations produced by external blows, +and also prevent fractures from extending as far as they otherwise +would, in one continued bone. From infancy to the twelfth year, the +sutures are imperfect; but, from that time to thirty-five or forty, +they are distinctly marked; in old age, they are nearly obliterated. + +[Illustration: Fig. 7. 1, 1, The coronal suture at the front and upper +part of the skull, or cranium. 2, The sagittal suture on the top of the +skull. 3, 3, The lambdoidal suture at the back part of the cranium.] + +79. We find as great a diversity in the form and texture of the +skull-bone, as in the expression of the face. The head of the New +Hollander is small; that of the African is compressed; while the +Caucasian is distinguished for the beautiful oval form of the head. +The Greek skulls, in texture, are close and fine, while the Swiss are +softer and more open. + + -=-=-=-=-=-=-=-=-=-=-=-= + +78. How are the bones of the skull united? What are the uses of the +sutures? Mention the appearance of the sutures at different ages. What +does fig. 7 represent? 79. What is said respecting the form and +texture of the skull in different nations? + + -=-=-=-=-=-=-=-=-=-=-=-= + +80. In each EAR are four very small bones. They aid in hearing. + +81. In the FACE are fourteen bones, some of which serve for the +attachment of powerful muscles, which are more or less called into +action in masticating food; others retain in place the soft parts of +the face. + +[Illustration: Fig. 8. 1, The frontal, or bone of the forehead. 2. The +parietal bone. 3, The temporal bone. 4, The zygomatic process of the +temporal bone. 5, The malar (cheek) bone. 6, The superior maxillary bone, +(upper jaw.) 7, The vomer, that separates the cavities of the nose. 8, +The inferior maxillary bone, (lower jaw.) 9. The cavity for the eye.] + +82. The TRUNK has fifty-four bones--twenty-four _Ribs_; twenty-four +bones in the _Spi'nal Col'umn_, (back-bone;) four in the _Pel'vis_; +the _Ster'num_, (breast-bone;) and the _Os hy-oid'es_, (the bone at +the base of the tongue.) They are so arranged as to form, with the +soft parts attached to them, two cavities, called the _Tho'rax_ +(chest) and _Ab-do'men_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +80. How many bones in the ear? 81. How many bones in the face? What is +their use? Explain fig. 8. 82-94. _Give the anatomy of the bones of +the trunk._ 82. How many bones in the trunk? Name them. What do they +form by their arrangement? + + -=-=-=-=-=-=-=-=-=-=-=-= + +83. The THORAX is formed by the sternum in front; the ribs, at the +sides; and the twelve dorsal bones of the spinal column, posteriorly. +The natural form of the chest is a cone, with its apex above; but +fashion, in many instances, has nearly inverted this order. This +cavity contains the lungs, heart, and large blood-vessels. + +[Illustration: Fig. 9. 1, The first bone of the sternum, (breast-bone.) +2. The second bone of the sternum. 3, The cartilage of the sternum. 4, +The first dorsal vertebra, (a bone of the spinal column.) 5, The last +dorsal vertebra. 6, The first rib. 7, Its head. 8, Its neck. 9, Its +tubercle. 10, The seventh, or last true rib. 11, The cartilage of the +third rib. 12, The floating ribs.] + +84. The STERNUM is composed of eight pieces in the child. These unite +and form but three parts in the adult. In youth, the two upper +portions are converted into bone, while the lower portion remains +cartilaginous and flexible until extreme old age, when it is often +converted into bone. + +85. The RIBS are connected with the spinal column, and increase in +length as far as the seventh. From this they successively become +shorter. The direction of the ribs from above, downward, is oblique, +and their curve diminishes from the first to the twelfth. The external +surface of each rib is convex; the internal, concave. The inferior, or +lower ribs, are, however, very flat. + + -=-=-=-=-=-=-=-=-=-=-=-= + +83. Describe the thorax. Explain fig. 9. 84. Describe the sternum. 85. +Describe the ribs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +86. The seven upper ribs are united to the sternum, through the medium +of cartilages, and are called the _true ribs_. The cartilages of the +next three are united with each other, and are not attached to the +sternum; these are called _false ribs_. The lowest two are called +_floating ribs_, as they are not connected either with the sternum or +the other ribs. + +87. The SPINAL COLUMN is composed of twenty-four pieces of bone. Each +piece is called a _vert'e-bra_. On examining one of the bones, we find +seven projections, called _processes_; four of these, that are +employed in binding the bones together, are called _articulating_ +processes; two of the remaining are called the _transverse_; and the +other, the _spinous_. The last three give attachment to the muscles of +the back. + +88. The large part of the vertebra, called the body, is round and +spongy in its texture, like the extremity of the round bones. The +processes are of a more dense character. The projections are so +arranged that a tube, or canal, is formed immediately behind the +bodies of the vertebrae, in which is placed the _me-dul'la spi-na'lis_, +(spinal cord,) sometimes called the pith of the back-bone. + +89. Between these joints, or vertebrae, is a peculiar and highly +elastic substance, which much facilitates the bending movements of the +back. This compressible cushion of cartilage also serves the important +purpose of diffusing and diminishing the shock in walking, running, or +leaping, and tends to protect the delicate texture of the brain. + + -=-=-=-=-=-=-=-=-=-=-=-= + +86. How are the ribs united to the sternum? 87. Describe the spinal +column. 88. Give the structure of the vertebra. Where is the spinal +cord placed? 89. What is placed between each vertebra? What is its +use? + + -=-=-=-=-=-=-=-=-=-=-=-= + +90. Another provision for the protection of the brain, which bears +convincing proof of the wisdom and beneficence of the Creator, is the +antero-posterior, or forward and backward curve of the spinal column. +Were it a straight column, standing perpendicularly, the slightest +jar, in walking, would cause it to recoil with a sudden jerk; because, +the weight bearing equally, the spine would neither yield to the one +side nor the other. But, shaped as it is, we find it yielding in the +direction of the curves, and thus the force of the shock is diffused. + +[Illustration: Fig. 10. A vertebra of the neck. 1, The body of the +vertebra. 2, The spinal canal. 4, The spinous process, cleft at its +extremity. 5, The transverse process. 7, The inferior articulating +process. 8, The superior articulating process.] + +[Illustration: Fig. 11. 1, The cartilaginous substance that connects the +bodies of the vertebrae. 2, The body of the vertebra. 3, The spinous +process. 4, 4, The transverse processes. 5, 5, The articulating +processes. 6, 6, A portion of the bony bridge that assists in forming the +spinal canal, (7.)] + +_Observation._ A good idea of the structure of the vertebrae may be +obtained by examining the spinal column of a domestic animal, as the +dog, cat, or pig. + +91. The PELVIS is composed of four bones; the two _in-nom-i-na'ta_, +(nameless bones,) the _sa'crum_, and the _coc'cyx_. + +92. The INNOMINATUM, in the child, consists of three pieces. These, +in the adult, become united, and constitute but one bone. In the sides +of these bones is a deep socket, or depression, like a cup, called the +_ac-e-tab'u-lum_, in which the round head of the thigh-bone is +placed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +90. What is said of the curves of the spinal column? What is +represented by fig. 10? By fig. 11? How can the structure of the +vertebrae be seen? 91. Of how many bones is the pelvis composed? 92. +What is said of the innominatum in the child? + + -=-=-=-=-=-=-=-=-=-=-=-= + +93. The SACRUM, so called because the ancients offered it in +sacrifices, is a wedge-shaped bone, that is placed between the +innominata, and to which it is bound by ligaments. Upon its upper +surface it connects with the lower vertebra. At its inferior, or lower +angle, it is united to the coccyx. It is concave upon its anterior, +and convex upon its posterior surface. + +[Illustration: Fig. 12. 1, 1, The innominata, (nameless bones.) 2, The +sacrum. 3, The coccyx. 4, 4, The acetabulum. a, a, The pubic portion of +the innominata. d, The arch of the pubes; e, The junction of the sacrum +and lower lumbar vertebra.] + +94. The COCCYX, in infants, consists of several pieces, which, in +youth, become united and form one bone. This is the terminal extremity +of the spinal column. + + -=-=-=-=-=-=-=-=-=-=-=-= + +In the adult? Describe the acetabulum. 93. Describe the sacrum. +Explain fig. 12. 94. Describe the coccyx. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER V. + +ANATOMY OF THE BONES, CONTINUED + + +95. The bones of the upper and lower limbs are enlarged at each +extremity, and have projections, or processes. To these, the tendons +of muscles and ligaments are attached, which connect one bone with +another. The shaft of these bones is cylindrical and hollow, and in +structure, their exterior surface is hard and compact, while the +interior portion is of a reticulated character. The enlarged +extremities of the round bones are more porous than the main shaft. + +96. The UPPER EXTREMITIES contain sixty-four bones--the _Scap'u-la_, +(shoulder-blade;) the _Clav'i-cle_, (collar-bone;) the _Hu'mer-us_, +(first bone of the arm;) the _Ul'na_ and _Ra'di-us_, (bones of the +fore-arm;) the _Car'pus_, (wrist;) the _Met-a-car'pus_, (palm of the +hand;) and the _Pha-lan'ges_, (fingers and thumb.) + +97. The CLAVICLE is attached, at one extremity, to the sternum; at the +other, it is united to the scapula. It is shaped like the Italic +_[s]_. Its use is to keep the arms from sliding toward the breast. + +98. The SCAPULA is situated upon the upper and back part of the chest. +It is flat, thin, and of a triangular form. This bone lies upon and is +retained in its position by muscles. By their contractions it may be +moved in different directions. + +99. The HUMERUS is cylindrical, and is joined at the elbow with the +ulna of the fore-arm; at the scapular extremity, it is lodged in the +_glenoid_ cavity, where it is surrounded by a membranous bag, called +the _capsular ligament_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +95-104. _Give the anatomy of the bones of the upper extremities._ 95. +Give the structure of the bones of the extremities. 96. How many bones +in the upper extremities? Name them. 97. Give the attachments of the +clavicle. What is its use? 98. Describe the scapula. How is it +retained in its position? 99. Describe the humerus. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 13. 1, The shaft of the humerus. 2, The large, round +head that is placed in the glenoid cavity. 3, 4, Processes, to which +muscles are attached. 5, A process, called the external elbow. 6, A +process, called the internal elbow. 7, The articulating surface upon +which the ulna rolls.] + +[Illustration: Fig. 14. 1, The body of the ulna. 2, The shaft of the +radius. 3, The upper articulation of the radius and ulna. 4, Articulating +cavity, in which the lower extremity of the humerus is placed. 5, Upper +extremity of the ulna, called the olecranon process, which forms the +point of the elbow. 6, Space between the radius and ulna, filled by the +intervening ligament. 7, Styloid process of the ulna. 8, Surface of the +radius and the ulna, where they articulate with the bones of the wrist. +9, Styloid process of the radius.] + +100. The ULNA articulates with the humerus at the elbow, and forms a +perfect hinge-joint. This bone is situated on the inner side of the +fore-arm. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is represented by fig. 13? By fig. 14? 100. Describe the ulna. + + -=-=-=-=-=-=-=-=-=-=-=-= + +101. The RADIUS articulates with the bones of the carpus and forms the +wrist-joint. This bone is situated on the outside of the fore-arm, +(the side on which the thumb is placed.) The ulna and radius, at their +extremities, articulate with each other, by which union the hand is +made to rotate, permitting its complicated and varied movements. + +102. The CARPUS is composed of eight bones, ranged in two rows, and so +firmly bound together, as to permit only a small amount of movement. + +[Illustration: Fig. 15. U, The ulna. R, The radius. S, The scaphoid bone. +L, The semilunar bone. C, The cuneiform bone. P, The pisiform bone. These +four form the first row of carpal bones. T, T, The trapezium and +trapezoid bones. M, The os magnum. U, The unciform bone. These four form +the second row of carpal bones. 1, 1, 1, 1, 1, The metacarpal bones of +the thumb and fingers.] + +[Illustration: Fig. 16. 10, 10, 10, The metacarpal bones of the hand. 11, +11, First range of finger-bones. 12, 12, Second range of finger-bones. +13, 13, Third range of finger-bones. 14, 15, Bones of the thumb.] + +103. The METACARPUS is composed of five bones, upon four of which the +first range of the finger-bones is placed; and upon the other, the +first bone of the thumb. The five metacarpal bones articulate with the +second range of carpal bones. + + -=-=-=-=-=-=-=-=-=-=-=-= + +101. The radius. 102. How many bones in the carpus? How are they +ranged? 103. Describe the metacarpus. + + -=-=-=-=-=-=-=-=-=-=-=-= + +104. The PHALANGES of the fingers have three ranges of bones, while +the thumb has but two. + +_Observation._ The wonderful adaptation of the hand to all the +mechanical offices of life, is one cause of man's superiority over the +rest of creation. This arises from the size and strength of the +thumbs, and the different lengths of the fingers. + +105. The LOWER EXTREMITIES contain sixty bones--the _Fe'mur_, +(thigh-bone;) the _Pa-tel'la_, (knee-pan;) the _Tib'i-a_, (shin-bone;) +the _Fib'u-la_, (small bone of the leg;) the _Tar'sus_, (instep;) the +_Met-a-tar'sus_, (middle of the foot;) and the _Pha-lan'ges_, (toes.) + +106. The FEMUR is the longest bone in the system. It supports the +weight of the head, trunk, and upper extremities. The large, round +head of this bone is placed in the acetabulum. This articulation is a +perfect specimen of the ball and socket joint. + +107. The PATELLA is a small bone connected with the tibia by a strong +ligament. The tendon of the _ex-tens'or_ muscles of the leg is +attached to its upper edge. This bone is placed on the anterior part +of the lower extremity of the femur, and acts like a pulley, in the +extension of the limb. + +108. The TIBIA is the largest bone of the leg. It is of a triangular +shape, and enlarged at each extremity. + +109. The FIBULA is a smaller bone than the tibia, but of similar +shape. It is firmly bound to the tibia, at each extremity. + +110. The TARSUS is formed of seven irregular bones, which are so +firmly bound together as to permit but little movement. + + -=-=-=-=-=-=-=-=-=-=-=-= + +104. How many ranges of bones have the phalanges? 105-112. _Give the +anatomy of the bones of the lower extremities._ 105. How many bones in +the lower extremities? Name them. 106. Describe the femur. 107. +Describe the patella. What is its function? 108. What is the largest +bone of the leg called? What is its form? 109. What is said of the +fibula? 110. Describe the tarsus. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 17. 1, The shaft of the femur, (thigh-bone.) 2, A +projection, called the trochantar minor, to which are attached some +strong muscles. 4, The trochantar major, to which the large muscles of +the hip are attached. 3, The head of the femur. 5, The external +projection of the femur, called the external condyle. 6, The internal +projection, called the internal condyle. 7, The surface of the lower +extremity of the femur, that articulates with the tibia, and upon which +the patella slides.] + +[Illustration: Fig. 18. 1, The tibia. 5, The fibula. 8, The space between +the two, filled with the inter-osseous ligament. 6, The junction of the +tibia and fibula at their upper extremity. 2, The external malleolar +process, called the external ankle. 3, The internal malleolar process, +called the internal ankle. 4, The surface of the lower extremity of the +tibia, that unites with one of the tarsal bones to form the ankle-joint. +7, The upper extremity of the tibia, upon which the lower extremity of +the femur rests.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 17. Explain fig. 18. + + -=-=-=-=-=-=-=-=-=-=-=-= + +111. The METATARSAL bones are five in number. They articulate at one +extremity with one range of tarsal bones; at the other extremity, with +the first range of the toe-bones. + +[Illustration: Fig. 19. A representation of the upper surface of the +bones of the foot. 1, The surface of the astragulus, where it unites with +the tibia. 2, The body of the astragulus. 3, The calcis, (heel-bone.) 4, +The scaphoid bone. 5, 6, 7, The cuneiform bones. 8, The cuboid. 9, 9, 9, +The metatarsal bones. 10, The first bone of the great toe. 11, The second +bone. 12, 13, 14, Three ranges of bones, forming the small toes] + +[Illustration: Fig. 20. A side view of the bones of the foot, showing its +arched form. The arch rests upon the _heel_ behind, and the _ball_ of the +toes in front. 1, The lower part of the tibia. 2, 3, 4, 5, Bones of the +tarsus. 6, The metatarsal bone. 7, 8, The bones of the great toe. These +bones are so united as to secure a great degree of elasticity, or spring.] + +_Observation._ The tarsal and metatarsal bones are united so as to +give the foot an arched form, convex above, and concave below. This +structure conduces to the elasticity of the step, and the weight of +the body is transmitted to the ground by the spring of the arch, in a +manner which prevents injury to the numerous organs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +111. Describe the metatarsal bones. Explain fig. 19. What is +represented by fig. 20? What is said of the arrangement of the bones +of the foot? + + -=-=-=-=-=-=-=-=-=-=-=-= + +112. The PHALANGES (fig. 19) are composed of fourteen bones; each of +the small toes has three ranges of bones, while the great toe has but +two. + +113. The JOINTS form an interesting part of the body. In their +construction, every thing shows the regard that has been paid to the +security and the facility of motion of the parts thus connected +together. They are composed of the extremities of two or more +bones, _Car'ti-lages_, (gristles,) _Syn-o'vi-al_ membrane, and +_Lig'a-ments_. + +[Illustration: Fig. 21 The relative position of the bones, cartilages, +and synovial membrane. 1, 1, The extremities of two bones that concur to +form a joint. 2, 2, The cartilages that cover the end of the bones. 3, 3, +3, 3, The synovial membrane which covers the cartilage of both bones, and +is then doubled back from one to the other; it is represented by the +dotted lines.] + +[Illustration: Fig. 22. A vertical section of the knee-joint. 1, The +femur. 3, The patella. 5, The tibia. 2, 4, The ligaments of the patella. +6, The cartilage of the tibia 12, The cartilage of the femur. * * * *, +The synovial membrane.] + +114. CARTILAGE is a smooth, solid, elastic substance, of a pearly +whiteness, softer than bone. It forms upon the articular surfaces of +the bones a thin incrustation, not more than the sixteenth of an inch +in thickness. Upon convex surfaces it is the thickest in the centre, +and thin toward the circumference; while upon concave surfaces, an +opposite arrangement is presented. + + -=-=-=-=-=-=-=-=-=-=-=-= + +112. Describe the phalanges. 113-118. _Give the anatomy of the +joints._ 113. What is said of the joints? Of what are the joints +composed? What is illustrated by fig. 21? By fig. 22? 114. Define +cartilage. + + -=-=-=-=-=-=-=-=-=-=-=-= + +115. The SYNOVIAL MEMBRANE is a thin, membranous layer, which covers +the cartilages, and is thence bent back, or reflected upon the inner +surfaces of the ligaments which surround and enter into the +composition of the joints. This membrane forms a closed sac, like the +membrane that lines an egg-shell. + +[Illustration: Fig. 23. The anterior ligaments of the knee-joint. 1, The +tendon of the muscle that extends the leg. 2, The patella. 3, The +anterior ligament of the patella, near its insertion. 4, 4, The synovial +membrane. 5, The internal lateral ligament. 6, The long external lateral +ligament. 7, The anterior and superior ligament that unites the fibula to +the tibia.] + +[Illustration: Fig. 24. 2, 3, The ligaments that extend from the clavicle +(1) to the scapula (4.) The ligaments 5, 6, extend from the scapula to +the first bone of the arm.] + +116. Beside the synovial membrane, there are numerous smaller sacs, +called _bur'sae mu-co'sae_. These are often associated with the +articulation. In structure, they are analogous to synovial membranes, +and secrete a similar fluid. + + -=-=-=-=-=-=-=-=-=-=-=-= + +115. Describe the synovial membrane. 116. Describe the bursae mucosae. +What is represented by fig. 23? By fig. 24? + + -=-=-=-=-=-=-=-=-=-=-=-= + +117. The LIGAMENTS are composed of numerous straight fibres, collected +together, and arranged into short bands of various breadths, or so +interwoven as to form a broad layer, which completely surrounds the +articular extremities of the bones, and constitutes a capsular +ligament. These connecting bands are white, glistening, and inelastic. +Most of the ligaments are found exterior to the synovial membrane. + +118. The bones, cartilages, ligaments, and synovial membrane are +insensible when in health; yet they are supplied with organic nerves, +as well as with arteries, veins, and lymphatics. + +_Observation._ The joints of the domestic animals are similar in their +construction to those of man. To illustrate this part of the body, a +fresh joint of the calf or sheep may be used. After divesting the +joints of the skin, the satin-like bands, or ligaments, will be seen +passing from one bone to the other, under which may be observed the +membranous bag, called the capsular ligament. This is very smooth, as +it is lined with the soft synovial membrane, beneath which will be +seen the cartilage, that may be cut with a knife, and under this the +rough extremity of the ends of the bones. + + -=-=-=-=-=-=-=-=-=-=-=-= + +117. Of what are ligaments composed? What is the appearance of these +bands? Where are they found? 118. With what vessels are the cartilages +and ligaments supplied? How can the structure of the joints be +explained? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER VI. + +PHYSIOLOGY OF THE BONES. + + +119. The bones are the framework of the system. By their solidity and +form, they not only retain every part of the fabric in its proper +shape, but afford a firm surface for the attachment of the muscles and +ligaments. By means of the bones, the human frame presents to the eye +a wonderful piece of mechanism, uniting the most finished symmetry of +form with freedom of motion, and also giving security to many +important organs. + +120. To give a clear idea of the relative uses of the bones and +muscles, we will quote the comparison of another, though, as in other +comparisons, there are points of difference. The "bones are to the +body what the masts and spars are to the ship,--they give support and +the power of resistance. The muscles are to the bones what the ropes +are to the masts and spars. The bones are the levers of the system; by +the action of the muscles their relative positions are changed. As the +masts and spars of a vessel must be sufficiently firm to sustain the +action of the ropes, so the bones must possess the same quality to +sustain the action of the muscles in the human body." + +121. Some of the bones are designed exclusively for the protection of +the organs which they enclose. Of this number are those that form the +skull, the sockets of the eye, and the cavity of the nose. Others, in +addition to the protection they give to important organs, are useful +in movements of certain kinds. Of this class are the bones of the +spinal column, and ribs. Others are subservient to motion. Of this +class are the upper and lower extremities. + + -=-=-=-=-=-=-=-=-=-=-=-= + +119-128. _Give the physiology of the bones._ 119. How may the bones be +considered? 120. To what may the bones be compared? 121. Give the +different offices of the bones. + + -=-=-=-=-=-=-=-=-=-=-=-= + +122. The bones are subject to growth and decay; to removal of old, +useless matter, and the deposit of new particles, as in other tissues. +This has been tested by the following experiment. Some of the inferior +animals were fed with food that contained madder. In a few days, some +of the animals were killed, and their bones exhibited an unusually +reddish appearance. The remainder of the animals were, for a few +weeks, fed on food that contained no coloring principle. When they +were killed, their bones exhibited the usual color of such animals. +The coloring matter, which had been deposited, had been removed by the +action of the lymphatics. + +123. The extremities of the bones that concur in forming a joint, +correspond by having their respective configurations reciprocal. They +are, in general, the one convex, and the other concave. In texture +they are porous, and consequently more elastic than if more compact. +These are covered with a cushion of cartilage. The elastic character +of these parts acts as so many springs, in diminishing the jar which +important organs of the system would otherwise receive. + +124. The synovial membrane secretes a viscous fluid, which is called +_syn-o'vi-a_. This lubricating fluid of the joints enables the +surfaces of the bones and tendons to move smoothly upon each other, +thus diminishing the friction consequent on their action. + +_Observations._ 1st. In this secretion is manifested the skill and +omnipotence of the Great Architect; for no machine of human invention +supplies to itself, by its own operations, the necessary lubricating +fluid. But, in the animal frame, it is supplied in proper quantities, +and applied in the proper place, and at the proper time. + + -=-=-=-=-=-=-=-=-=-=-=-= + +122. What is said of the change in bones? How was it proved that there +was a constant change in the osseous fabric? 123. What is said of the +extremities of the bones that form a joint? 124. What is synovia? Its +use? What is said of this lubricating fluid? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. In some cases of injury and disease, the synovial fluid is +secreted in large quantities, and distends the sac of the joint. This +affection is called dropsy of the joint, and occurs most frequently in +that of the knee. + +125. The function of the ligaments is to connect and bind together the +bones of the system. By them the small bones of the wrist and foot, as +well as the large bones, are as securely fastened as if retained by +clasps of steel. Some of them are situated within the joints, like a +central cord, or pivot, (3, fig. 26.) Some surround it like a hood, +and contain the lubricating synovial fluid, (8, 9, fig. 25,) and some +in the form of bands at the side, (5, 6, fig. 23.) + +[Illustration: Fig. 25. 8, 9, The ligaments that extend from the hip-bone +(6) to the femur, (5.)] + +[Illustration: Fig. 26. 2, The socket of the hip-joint. 5, The head of +the femur, which is lodged in the socket. 3, The ligament within the +socket.] + +126. By the ligaments the lower jaw is bound to the temporal bones, +and the head to the neck. They extend the whole length of the spinal +column, in powerful bands, on the outer surface, between the spinal +bones, and from one spinous process to another. They bind the ribs to +the vertebrae, to the transverse process behind, and to the sternum in +front; and this to the clavicle; and this to the first rib and +scapula; and this last to the humerus. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is the effect when the synovial fluid is secreted in large +quantities? 125. What is the function of the ligaments? 126. Mention +how the bones of the system are connected. + + -=-=-=-=-=-=-=-=-=-=-=-= + +127. They also bind the two bones of the fore-arm at the elbow-joint; +and these to the wrist; and these to each other and to those of the +hand; and these last to each other and to those of the fingers and +thumb. In the same manner, they bind the bones of the pelvis together; +and these to the femur; and this to the two bones of the leg and +patella; and so on, to the ankle, foot, and toes, as in the upper +extremities. + +[Illustration: Fig. 27. 1, A front view of the lateral ligaments of the +finger-joints. 2, A view of the anterior ligaments (_a_, _b_,) of the +finger-joints. 3, A side view of the lateral ligaments of the finger +joints.] + +128. The different joints vary in range of movement, and in complexity +of structure. Some permit motions in all directions, as the shoulder; +some move in two directions, permitting only flexion and extension of +the part, as the elbow; while others have no movement, as the bones of +the head in the adult. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 27. 128. Describe the variety of movements in the +different joints. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 28. 1, 1, The spinal column. 2, The skull. 3, The +lower jaw. 4, The sternum. 5, The ribs. 6, 6, The cartilages of the ribs. +7, The clavicle. 8, The humerus. 9, The shoulder-joint. 10, The radius. +11, The ulna. 12, The elbow joint. 13, The wrist. 14, The hand. 15, The +haunch-bone. 16, The sacrum. 17, The hip-joint. 18, The thigh-bone. 19, +The patella. 20, The knee-joint. 21, The fibula. 22, The tibia. 23, The +ankle-joint. 24, The foot. 25, 26, The ligaments of the clavicle, +sternum, and ribs. 27, 28, 29, The ligaments of the shoulder, elbow, and +wrist. 30, The large artery of the arm. 31, The ligaments of the +hip-joint. 32, The large blood-vessels of the thigh. 33, The artery of +the leg. 34, 35, 36, The ligaments of the patella, knee, and ankle.] + +_Note._ Let the pupil, in form of topics, review the anatomy and +physiology of the bones from fig. 28, or from anatomical outline +plates No. 1 and 2. + + + + +CHAPTER VII + +HYGIENE OF THE BONES. + + +129. _The bones increase in size and strength by use, while they are +weakened by inaction._ Exercise favors the deposition of both animal +and earthy matter, by increasing the circulation and nutrition in this +texture. For this reason, the bones of the laborer are dense and +strong, while those who neglect exercise, or are unaccustomed to +manual employment, are deficient in size, and have not a due +proportion of earthy matter to give them the solidity and strength of +the laboring man. + +_Observation._ The tendons of the muscles are attached near the +extremities of the bones. Exercise of the muscles increases the action +of the vessels of that part to which the tendons are attached, and +thus increases the nutrition and size of this portion of the bone. +Hence the joints of an industrious mechanic or farmer are larger than +those of an individual who has not pursued manual vocations. + +130. _The gelatinous bones of the child are not so well adapted for +labor and severe exercise as those of an adult._ 1st. They are liable +to become distorted. 2d. They are consolidated by the deposition of +earthy material before they are fully and properly developed. If a +young animal, as the colt, be put to severe, continued labor, the +deposition of earthy matter is hastened, and the bones are +consolidated before they attain full growth. Such colts make small and +inferior animals. Similar results follow, if a youth is compelled to +toil unduly before maturity of growth is attained. On the other hand, +moderate and regular labor favors a healthy development and +consolidation of the bones. + + -=-=-=-=-=-=-=-=-=-=-=-= + +129-148. _Give the hygiene of the bones._ 129. What effect has +exercise upon the bones? What effect has inaction? Why are the joints +of the industrious farmer and mechanic larger than those of a person +unaccustomed to manual employment? 130. Give the first reason why the +bones of the child are not adapted to severe exercise. The second +reason. + + -=-=-=-=-=-=-=-=-=-=-=-= + +131. _The kind and amount of labor should be adapted to the age, +health, and development of the bones._ Neither the flexible bones of +the child nor the brittle bones of the aged man are adapted, by their +organization, to long-continued, and hard labor. Those of the one bend +too easily, while those of the other fracture too readily. In middle +age, the proportions of animal and earthy matter are, usually, such as +to give the proper degree of flexibility, firmness, and strength for +labor, with little liability to injury. + +132. _The imperfectly developed bones of the young child will not bear +long-continued exertions or positions without injury._ Hence the +requisitions of the rigid disciplinarian of schools, are unwise when +he compels his pupils to remain in one position for a long time. He +may have a "quiet school;" but, not unfrequently, by such discipline, +the constitution is impaired, and permanent injury is done to the +pupils. + +133. _The lower extremities, in early life, contain but a small +proportion of earthy matter_; they bend when the weight of the body is +thrown upon them for a long time. Hence, the assiduous attempts to +induce children to stand or walk, either naturally or artificially, +when very young, are ill advised, and often productive of serious and +permanent evil. The "bandy" or bow legs are thus produced. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What effect has moderate, regular labor upon the growing youth? 131. +What remark respecting the kind and amount of labor? At what age are +the bones best fitted for labor? 132. What effect has long-continued +exertions or positions on the bones of a child? What is said of the +requisitions of some teachers, who have the famed "quiet schools"? +133. Why should not the child be induced to stand or walk, either +naturally or artificially, at too early an age? + + -=-=-=-=-=-=-=-=-=-=-=-= + +134. _The benches or chairs for children in a school-room should be of +such a height as to permit the feet to rest on the floor._ If the +bench is so high as not to permit the feet to rest upon the floor, the +weight of the limbs below the knee may cause the flexible bone of the +thigh to become curved. The child thus seated, is inclined to lean +forward, contracting an injurious and ungraceful habit. Again, when +the feet are not supported, the child soon becomes exhausted, +restless, and unfit for study. In the construction of a school-room, +the benches should be of different heights, so as to be adapted to the +different pupils, and they should also have appropriate backs. + +[Illustration: Fig. 29. The position assumed when the seat is of proper +height, and the feet supported.] + +[Illustration: Fig. 30. The position a child naturally assumes when the +seat is so high that the feet are not supported.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +134. What is said of the benches or chairs in a school-room? What is +represented by fig. 29? By fig. 30? What is the effect when the lower +limbs are not supported? + + -=-=-=-=-=-=-=-=-=-=-=-= + +135. _Compression of the chest should be avoided._ In children, and +also in adults, the ribs are very flexible, and a small amount of +pressure will increase their curvature, particularly at the lower part +of the chest, and thus lessen the size of this cavity. The lower ribs +are united to the breast-bone, by long, yielding cartilages, and +compression may not only contract the chest, but an unseemly and +painful ridge may be produced, by the bending of the cartilages, on +one or both sides of the sternum. + +[Illustration: Fig. 31. A natural and well-proportioned chest.] + +[Illustration: Fig. 32. A chest fashionably deformed.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +135. Why should compression of the chest be avoided? What is +represented by fig. 31? By fig. 32? + + -=-=-=-=-=-=-=-=-=-=-=-= + +136. Again, the cartilages on one side may be bent outward, while +those on the opposite side are bent inward, thus forming a depression +parallel with the sternum. In some instances, the anterior extremity +of the lower ribs on each side are brought nearly or quite together. +In these instances, the movable extremities of the ribs are drawn down +toward the haunch-bones, while the space between the ribs is lessened. +All this may be effected by tight or "snug" clothing. Therefore the +apparel of a child should be loose, and supported over the shoulders, +to avoid the before-mentioned evils. The same may be said of the +clothing for adults. + +137. _The erect position in sitting and standing should be assiduously +observed._ The spinal column, in its natural position, curves from +front to back, but not from side to side The admirable arrangement of +the bones, alternating with cartilages, permits a great variety of +motions and positions; and when the spine is inclined to either side, +the elasticity of its cartilages tends to restore it to its natural +position. For this reason we may incline the spinal column in any +direction for a short time, without danger of permanent curvature, if, +afterward, the erect position is assumed.[4] + + [4] Compare 1, 1, Fig. 28, with 2, 2, 2, Fig. 48. + +138. But if a stooping position, or a lateral curved posture, is +continued for a long time, the spinal column does not easily recover +its proper position, for the compressed edges of the cartilages lose +their power of reaction, and finally one side of the cartilage becomes +thinned, while the other is thickened; and these wedge-shaped +cartilages produce a permanent curvature of the spinal column. In a +similar way, the student, seamstress, artisan, and mechanic acquire a +stooping position, and become round shouldered, by inclining forward +to bring their books or work nearer the eyes. + + -=-=-=-=-=-=-=-=-=-=-=-= + +136. May simply "snug" clothing compress the cartilages? How should +the apparel of a child be worn? 137. In what direction does the spinal +column, in its natural position, curve? What restores it to its +natural position when curved laterally? 138. What is the effect if a +lateral curved position of the spinal column is continued for a long +time? 139. When one shoulder is elevated for a long time, what is the +effect upon the spinal column? + + -=-=-=-=-=-=-=-=-=-=-=-= + +139. Pupils, while writing, drawing, and sometimes while studying, +frequently incline the spinal column to one side, in order to +accommodate themselves to the desks at which they are seated. Often, +these are higher than the elbow as it hangs from the shoulder while at +rest. This attitude elevates one shoulder while it depresses the +other; consequently, the upper part of the spinal column is inclined +toward the elevated shoulder, and the lower part is curved in the +opposite direction, giving the form of the letter _S_ to the +supporting column of the body. + +[Illustration: Fig. 33. The table is of proper height, the position is +correct, and the spinal column, 1, 1, is straight, while the shoulders +are of equal height.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does fig. 33 represent? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Experiment._ Let a pupil be placed at a desk or table with one elbow +raised, as is frequently seen while writing, or at study, and observe +the condition of the shoulder and spinal column in this position. +Place another pupil at a table no higher than the elbow when it hangs +by the side while sitting, and observe the appearance of the shoulders +and spinal column. By a comparison of the two attitudes, the preceding +remarks will be comprehended and appreciated. + +[Illustration: Fig. 34. The table is too high, and the position is +oblique and improper. The right shoulder is seen higher than the left, +while the spinal column, 1, 1, exhibits three curves.] + +140. One shoulder may be elevated, and no injurious results follow, +provided care is taken not to keep it in the raised position too long, +or if the opposite shoulder is elevated for the same period of time. +The right shoulder projects more frequently than the left. This arises +from the greater use of the right hand with the shoulder elevated, and +not unfrequently the oblique positions assumed in performing the daily +vocations of life. With proper care, and by calling into action the +left shoulder, this deformity can be prevented. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What experiment is mentioned? What does fig. 34 represent? 140. How +can one shoulder be elevated and no injurious results follow? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 35. A representation of a deformed trunk.] + +141. The loss of symmetry and diminution of height from deformed +spines are minor considerations, compared with the distortions that +the chest experiences, thereby impairing respiration and inducing +diseases of the heart and lungs. The invasion of the functions of +these two important organs lessens the vitality of the whole system, +and causes general ill health. Again, the curvature of the spinal +column is frequently attended by irritation and disease of the spinal +cord. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Why does the right shoulder project more frequently than the left? How +can this deformity be prevented? 141. What is said of deformed spinal +columns? + + -=-=-=-=-=-=-=-=-=-=-=-= + +142. Eminent physicians, both in this country and France state that +not more than one female in ten, who has been fashionably educated, is +free from deformities of the shoulder or spinal column. Teachers, as +well as mothers, should notice the positions of the child in +performing the tasks allotted to it, whether studying or pursuing any +employment. The feebler the organization of the child, the more +frequently should there be a change of position. + +143. When a slight projection of the shoulder, with a curvature of the +spine, exists, it can be improved by walking with a book, or something +heavier, upon the head; to balance which, the spinal column must be +nearly erect. Those people that carry burdens upon their heads seldom +have crooked spines. + +_Observation._ Persons from the North, in travelling through the +Southern States, are surprised to see the heavy burdens that the +porters carry on their heads. It is not unusual to see them walking at +a rapid pace, with one or two trunks, weighing fifty or eighty pounds +each, upon their heads. Occasionally, we meet an itinerant toy-man, +with his tray of fragile merchandise upon his head, walking with as +much apparent security, as though his toys, or images, were in his +hands. This is the easiest method of carrying burdens, because the +position of the head and spinal column is erect. + +144. _If the animal and earthy matter of the bones is not deposited in +proper proportions, they are deficient in strength._ If the gelatin +predominates, the bones are weak, and become distorted. When +nutrition is defective in the cylindrical bones, the heads are +generally enlarged, and the shafts crooked; if in the spinal column, +it may be curved; or in the cranium, it may be enlarged. This disease +is familiarly known by the name of rickets. It is most common among +these who have poor and insufficient food, live in dark, damp rooms, +and breathe a vitiated air. The prevention and remedies for this +disease are cleanliness, regular exercise, pure air, and nutritious +food. + + -=-=-=-=-=-=-=-=-=-=-=-= + +142. What statement by eminent physicians respecting deformities of +the spine? What caution to teachers and mothers? 143. Why should we +stand and sit erect? How may slight deformities of the spine be +prevented? What is frequently noticed in travelling South? 144. What +is the effect upon the bones when the gelatin preponderates? + + -=-=-=-=-=-=-=-=-=-=-=-= + +145. When a bone is broken, some days elapse before the substance that +reunites it is thrown out from the blood. In young persons, it may be +secreted during the second or third week, and in individuals advanced +in life, usually during the third and fourth week. When the bone is +uniting, during the second, third, or fourth week, the attention of a +surgeon is more needed than during the first week. At this time, the +ends of the bone should be placed together with accuracy, which +requires the careful application of proper dressing. After the bones +have united, it will take some weeks to consolidate the uniting +material and render the "callus," or union, firm. During this time, +the limb should be used with care. + +_Observation._ When a bone is fractured, a surgeon is immediately +called, and the bone is "set." While the limb remains swelled and +painful, the surgeon is required to attend and keep the dressings +(bandages and splints) on. When the swelling has abated, and the pain +subsided, frequently the patient intimates to the surgeon that his +services can be dispensed with, as the "limb is doing well." This is +the most important period, as the bone is uniting, and, unless the +ends are nicely adjusted, the dressing properly applied, the person +will find, on recovery, a shortened and crooked limb. The surgeon is +then censured, when he is not blamable. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is one cause of rickets? What are the prevention and remedies for +this disease? 145. Does the time vary when the reuniting substance of +the bone is secreted from the blood? When is the surgeon's care most +needed? Why? + + -=-=-=-=-=-=-=-=-=-=-=-= + +146. It is seldom that a bone is displaced without injury to the +connecting ligaments and membranes. When these connecting bands are +lacerated, pain, swelling, and other symptoms indicating inflammation +succeed, which should be removed by proper treatment, directed by a +surgical adviser. + +147. In sprains, but few, if any, of the fibres of the connecting +ligaments are lacerated; but they are unduly strained and twisted, +which occasions acute pain at the time of the injury. This is followed +by inflammation and weakness of the joints. The treatment of these +injuries is similar to that of a dislocated bone after its reduction. +The most important item in the treatment during the few first days, is +rest. + +148. In persons of scrofulous constitutions, and those in whom the +system is enfeebled by disease, white swellings and other chronic +diseases of the joints frequently succeed sprains. Such persons cannot +be too assiduous in adopting a proper and early treatment of injured +joints. + + -=-=-=-=-=-=-=-=-=-=-=-= + +146. What parts are injured in the displacement of a bone? 147. What +causes the acute pain in sprains? What is a good remedy for this kind +of injury? 148. What caution to persons of scrofulous constitutions? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER VIII + +THE MUSCLES. + + +149. All the great motions of the body are caused by the movement of +some of the bones which form the framework of the system; but these, +independently of themselves, have not the power of motion, and only +change their position through the action of other organs attached to +them, which, by contracting, draw the bones after them. In some of the +slight movements, as the winking of the eye, no bones are displaced. +These moving, contracting organs are the _Mus'cles_, (lean meat.) + + +ANATOMY OF THE MUSCLES. + +150. The MUSCLES, by their size and number, constitute the great bulk +of the body, upon which they bestow form and symmetry. In the limbs, +they are situated around the bones, which they invest and defend, +while they form, to some of the joints, their principal protection. In +the trunk, they are spread out to enclose cavities, and constitute a +defensive wall, capable of yielding to internal pressure, and +reassuming its original state. + +151. In structure, a muscle is composed of _fas-cic'u-li_ (bundles of +fibres) of variable size. These are enclosed in a cellular membranous +investment, or sheath. Every bundle composed of a number of small +fibres, and each fibre consists of a number of filaments, each of +which is enclosed in a delicate sheath. Toward the extremity of the +organ the muscular fibre ceases, and the cellular structure becomes +aggregated, and so modified as to constitute _ten'dons_, (cords,) by +which the muscle is tied to the surface of the bone. The union is so +firm, that, under extreme violence, the bone will sooner break than +permit the tendon to separate from its attachment. In some situations, +there is an expansion of the tendon, in the manner of a membrane, +called _Ap-o-neu-ro'sis_, or _Fas'ci-a_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +149. How are all the motions of the body produced? What are these +motor organs called? 150-160. _Give the anatomy of the muscles._ 150. +What is said of the muscles? 151. Give their structure. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ The pupil can examine a piece of boiled beef, or the +leg of a fowl, and see the structure of the fibres and tendons of a +muscle. + +[Illustration: Fig. 36. 1, A representation of the direction and +arrangement of the fibres in a fusiform, or spindle-shaped muscle. 2, In +a radiated muscle. 3, In a penniform muscle. 4, In a bipenniform muscle. +_t_, _t_, The tendons of a muscle.] + +152. Muscles present various modifications in the arrangement of their +fibres, as relates to their tendinous structure. Sometimes they are +completely longitudinal, and terminate, at each extremity, in a +tendon, the entire muscle being spindle-shaped. In other situations, +they are disposed like the rays of a fan, converging to a tendinous +point, and constituting a _ra'di-ate_ muscle. Again they are +_pen'ni-form_, converging, like the plumes of a pen, to one side of a +tendon, which runs the whole length of the muscle; or they are +_bi-pen'ni-form_, converging to both sides of the tendon. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How are tendons or cords formed? What is the expansion of a tendon +called? How can the structure of muscles and their fibres be shown? +What does fig. 36 represent? 152. Give the different arrangements of +muscular fibres. + + -=-=-=-=-=-=-=-=-=-=-=-= + +153. In the description of a muscle, its attachments are expressed by +the terms "origin" and "insertion." The term _origin_ is generally +applied to the more fixed or central attachment, or to the point +toward which motion is directed; while _insertion_ is assigned to the +more movable point, or to that most distant from the centre. The +middle, fleshy portion is called the "belly," or "swell." The color of +a muscle is red in warm-blooded fish and animals; and each fibre is +supplied with arteries, veins, lymphatics, and both sensitive and +motor nervous filaments. + +154. The FASCIA is of various extent and thickness, distributed +through the different regions of the body, for the purpose of +investing and protecting the softer and more delicate organs. An +instance is seen in the membrane which envelopes a leg of beef, and +which is observed on the edges of the slices when it is cut for +broiling. When freshly exposed, it is brilliant in appearance, tough, +and inelastic. In the limbs it forms distinct sheaths to all the +muscles. + +155. This tendinous membrane assists the muscles in their action, by +keeping up a tonic pressure on their surface. It aids materially in +the circulation of the fluids, in opposition to the laws of gravity. +In the palm of the hand and sole of the foot, it is a powerful +protection to the structures that enter into the formation of these +parts. In all parts of the system, the separate muscles are not only +invested by fascia, but they are arranged in layers, one over +another. The sheath of each muscle is loosely connected with another, +by the cellular membrane. + + -=-=-=-=-=-=-=-=-=-=-=-= + +153. What is meant by the origin of a muscle? The insertion? The +swell? What is the color of muscles? With what is each muscular fibre +supplied? 154. What is said of fascia? What is its appearance when +freshly exposed? 155. What effect has it on the muscles? Give other +uses of the fascia. + + -=-=-=-=-=-=-=-=-=-=-=-= + +156. The interstices between the different muscles are filled with +adipose matter, or fat. This is sometimes called the packing of the +system. To the presence of this tissue, youth are indebted for the +roundness and beauty of their limbs. + +[Illustration: Fig. 37. A transverse section of the neck. The separate +muscles, as they are arranged in layers, with their investing fasciae, are +beautifully represented. As the system is symmetrical, figures are placed +only on one side. In the trunk the muscles are arranged in layers, +surrounded by fasciae, as in the neck. The same is true of the muscles of +the upper and lower limbs. + +12, The trachea, (windpipe.) 13, The oesophagus, (gullet.) 14, The +carotid artery and jugular vein. 28, One of the bones of the spinal +column. The figures that are placed in the white spaces represent some of +the fasciae; the other figures indicate muscles.] + +157. The muscles may be arranged, in conformity with the general +division of the body, into four parts: 1st. Those of the _Head_ +and _Neck_. 2d. Those of the _Trunk_. 3d. Those of the _Upper +Extremities_. 4th. Those of the _Lower Extremities_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +156. Give a reason why the limbs of youth are rounder than those of +the aged. Describe fig. 37. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 38. The superficial layer of muscles on the face and +neck. 1, 1, The occipito-frontalis muscle. 2, The orbicularis +palpebrarum. 6, The levator labii superioris 7, The levator anguli oris. +8, The zygomaticus minor. 9, The zygomaticus major 10, The masseter. 11, +The depressor labii superioris. 13, The orbicularis oris. 15, The +depressor anguli oris. 16, The depressor labii inferioris. 18, The +sterno-hyoideus. 19, The platysma-myodes. 20, The superior belly of the +omo-hyoideus. 21, The sterno-cleido mastoideus. 20, The scalenus medius. +23, The inferior belly of the omo-hyoideus. 24, The trapezius.[5] + +_Practical Explanation._ The muscle 1, 1, elevates the eyebrows. The +muscle 2 closes the eye. The muscle 6 elevates the upper lip. The muscles +7, 8, 9, elevate the angle of the mouth. The muscle 10 brings the teeth +together when eating. The muscle 11 depresses the upper lip. The muscle +13 closes the mouth. The muscle 15 depresses the angle of the mouth. The +muscle 16 draws down the lower lip. The muscles 18, 19, 20, 23, depress +the lower jaw and larynx and elevate the sternum. The muscle 21, when +both sides contract, draws the head forward, or elevates the sternum; +when only one contracts, the face is turned one side toward the opposite +shoulder. The muscles 18, 19, 20, 21, 22, 23, 24, aid in respiration.] + + [5] In the plates illustrating the muscular system, the names of such + muscles are given as are referred to in the paragraph + "Practical Explanation." These names need not be committed to + memory. If a pupil wishes to acquire a knowledge of the general + attachment of the muscles represented in the plates, he can do + so by _comparing_ the muscular plate with that of the skeleton, + (fig. 28.) + +_Observation._ When we are sick, and cannot take food, the body is +sustained by absorption of the fat. The removal of it into the blood +causes the sunken cheek, hollow eye, and prominent appearance of the +bones after a severe illness. + +158. The number of muscles in the human body is more than five +hundred; in general, they form about the skeleton two layers, and are +distinguished into superficial and deep-seated muscles. Some of the +muscles are voluntary in their motions, or act under the government of +the will, as those which move the fingers, limbs, and trunk; while +others are involuntary, or act under the impression of their proper +stimulants, without the control of the individual, as the heart. + +_Observations._ 1st. The abdominal muscles are expiratory, and the +chief agents for expelling the residuum from the rectum, the bile from +the gall bladder, the contents of the stomach and bowels when +vomiting, and the mucus and irritating substances from the bronchial +tubes, trachea, and nasal passages by coughing and sneezing. To +produce these effects they all act together. Their violent and +continued action sometimes produces hernia, and, when spasmodic, may +occasion ruptures of the different organs. + +2d. The contraction and relaxation of the abdominal muscles and +diaphragm stimulate the stomach, liver, and intestines to a healthy +action, and are subservient to the digestive powers. If the +contractility of their muscular fibres is destroyed or impaired, the +tone of the digestive apparatus will be diminished, as in indigestion +and costiveness. This is frequently attended by a displacement of +those organs, as they generally gravitate towards the lower portion of +the abdominal cavity, when the sustaining muscles lose their tone and +become relaxed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What causes the hollow eye and sunken cheek after a severe sickness? +158. How many muscles in the human system? Into how many layers are +they arranged? What is a voluntary muscle? Give examples. What is an +involuntary muscle? Mention examples. Give observation 1st, respecting +the use of the abdominal muscles? Observation 2d. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 39. A front view of the muscles of the trunk. On the +left side the superficial layer is seen; on the right, the deep layer. 1, +The pectoralis major muscle. 2, The deltoid muscle. 6, The pectoralis +minor muscle. 9, The coracoid process of the scapula. 11, The external +intercostal muscle. 12, The external oblique muscle 13, Its aponeurosis. +16, The rectus muscle of the right side. 18, The internal oblique muscle. + +_Practical Explanation._ The muscle 1 draws the arm by the side, and +across the chest, and likewise draws the scapula forward. The muscle 2 +elevates the arm. The muscle 6 elevates the ribs when the scapula is +fixed, or draws the scapula forward and downward when the ribs are fixed. +The muscles 12, 16, 18, bend the body forward or elevate the hips when +the muscles of both sides act. They likewise depress the rib in +expiration. When the muscles on only one side act, the body is twisted to +the same side.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 39. Give the function of some of the most prominent +muscles, from this figure. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 40. A lateral view of the muscles of the trunk. 3, +The upper part of the external oblique muscle. 4, Two of the external +intercostal muscles. 5, Two of the internal intercostals. 6, The +transversalis muscle. 7, Its posterior aponeurosis. 8, Its anterior +aponeurosis. 11, The right rectus muscle. 13, The crest of the ilium, or +haunch-bone. + +_Practical Explanation._ The rectus muscle, 11, bends the thorax upon the +abdomen when the lower extremity of the muscle is the fixed point; but +when the upper extremity is the fixed point, the effect is to bring +forward and raise the pelvis and lower extremities. They likewise depress +the ribs in respiration. The transverse muscle, 6, 7, 8, lessens the +cavity of the abdomen, and presses the intestines; stomach, and liver +upward, against the diaphragm, in expiration.] + +3d. The region of the back, in consequence of its extent, is common to +the neck, the upper extremities, and the abdomen. The muscles of which +it is composed are numerous, and are arranged in six layers. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is represented by fig. 40? Give the function of some of the +muscles represented by this figure. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 41 The first, second, and part of the third layer of +muscles of the back. The first layer is shown on the right, and the +second on the left side. 1, The trapezius muscle. 2, The spinous +processes of the vertebrae. 3, The acromion process and spine of the +scapula. 4, The latissimus dorsi muscle. 5, The deltoid muscle. 7, The +external oblique muscle. 8, The gluteus medius muscle. 9, The gluteus +maximus muscle, 11, 12, The rhomboideus major and minor muscles. 15, The +vertebral aponeurosis. 16, The serratus posticus inferior muscle. 22, The +serratus magnus muscle. 23, The internal oblique muscle. + +_Practical Explanation._ The muscles 1, 11, 12, draw the scapula back +toward the spine. The muscles 11, 12, draw the scapula upward toward the +head, and slightly backward. The muscle 4 draws the arm by the side, and +backward, The muscle 5 elevates the arm. The muscles 8, 9, extend the +thigh on the body. The muscle 1 draws the head back and elevates the +chin. The muscle 16 depresses the ribs in expiration. The muscle 22 +elevates the ribs in inspiration.] + +159. The diaphragm, or midriff, is the muscular division between the +thorax and the abdomen. It is penetrated by the oesophagus on its way +to the stomach, by the aorta conveying blood toward the lower +extremity, and by the ascending vena cava, or vein, on its way to the +heart. + +[Illustration: Fig. 42. A representation of the under, or abdominal side +of the diaphragm. 1, 2, 3, 4, The portion which is attached to the margin +of the ribs. 8, 10, The two fleshy pillars of the diaphragm, which are +attached to the third and fourth lumbar vertebrae. 9, The spinal column. +11, The opening for the passage of the aorta. 12, The opening for the +oesophagus. 13, The opening for the ascending vena cava, or vein.] + +_Observation._ The diaphragm may be compared to an inverted basin, its +bottom being turned upward into the thorax, while its edge corresponds +with the outline of the edges of the lower ribs and sternum. Its +concavity is directed toward the abdomen, and thus, this cavity is +very much enlarged at the expense of that of the chest, which is +diminished to an equal extent. + + -=-=-=-=-=-=-=-=-=-=-=-= + +159. Describe the diaphragm. What vessels penetrate this muscular +septum? + + -=-=-=-=-=-=-=-=-=-=-=-= + +160. "The motions of the fingers do not merely result from the action +of the large muscles which lie on the fore-arm, these being concerned +more especially in the stronger actions of the hands. The finer and +more delicate movements of the fingers are performed by small muscles +situated in the palm and between the bones of the hand, and by which +the fingers are expanded and moved in all directions with wonderful +rapidity." + +[Illustration: Fig. 43. A front view of the superficial layer of muscles +of the fore-arm. 5, The flexor carpi radialis muscle. 6, The palmaris +longus muscle. 7, One of the fasciculi of the flexor sublimis digitorum +muscle, (the rest of the muscle is seen beneath the tendons of the +pintails longus.) 8, The flexor carpi ulnaris muscle. 9, The palmar +fascia. 11, The abductor pollicis muscle. 12, One portion of the flexor +orevis pollicis muscle. 13, The supinator longus muscle. 14, The extensor +ossis metacarpi, and extensor primi internodii pollicis muscles, curving +around the lower border of the fore-arm. 15, The anterior portion of the +annular ligament, which binds the tendons in their places. + +_Practical Explanation._ The muscles 5, 6, 8, bend the wrist on the bones +of the fore-arm. The muscle 7 bends the second range of finger-bones on +the first. The muscle 11 draws the thumb from the fingers. The muscle 12 +flexes the thumb. The muscle 13 turns the palm of the hand upward. The +muscles 8, 13, 14, move the hand laterally.] + +[Illustration: Fig. 44. A back view of the superficial layer of muscles +of the fore-arm. 5, The extensor carpi radialis longior muscle. 6, The +extensor carpi radialis brevior muscle. 7, The tendons of insertion of +these two muscles. 8, The extensor communis digitorum muscle. 9, The +extensor minimi dlgiti muscle. 10, The extensor carpi ulnaris muscle. 13, +The extensor ossis metacarpi and extensor primi internodii muscles, lying +together. 14, The extensor secundi internodii muscle; its tendon is seen +crossing the two tendons of the extensor carpi radialis longior and +brevior muscles. 15, The posterior annular ligament. The tendons of the +common extensor muscle of the fingers are seen on the back of the hand, +and their mode of distribution on the back of the fingers. + +_Practical Explanation._ The muscles 5, 6, 10, extend the wrist on the +fore-arm. The muscle 8 extends the fingers. The muscle 9 extends the +little finger. The muscles 13 extend the metacarpal bone of the thumb, +and its first phalanx. The muscle 14 extends the last bone of the thumb. +The muscles 10, 13, 14, move the hand laterally.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +160. Where are the muscles situated that effect the larger movements +of the hand? That perform the delicate movements of the fingers? Give +the use of some of the muscles represented by fig. 43. Those +represented by fig. 44. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER IX. + +PHYSIOLOGY OF THE MUSCLES. + + +161. The muscles exercise great influence upon the system. It is by +their contraction that we are enabled to pursue different employments. +By their action the farmer cultivates his fields, the mechanic wields +his tools, the sportsman pursues his game, the orator gives utterance +to his thoughts, the lady sweeps the keys of the piano, and the young +are whirled in the mazy dance. As the muscles bear so intimate a +relation to the pleasures and employments of man, a knowledge of the +laws by which their action is governed, and the conditions upon which +their health depends, should be possessed by all. + +162. The peculiar characteristic of muscular fibres is _contractility_, +or the power of shortening their substance on the application of +stimuli, and again relaxing when the stimulus is withdrawn. This is +illustrated in the most common movements of life. Call into action the +muscles that elevate the arm, by the influence of the _will_, or mind, +(the common stimulus of the muscles,) and the hand and arm are +raised; withdraw this influence by a simple effort of the will, and +the muscles, before rigid and tense, become relaxed and yielding. + +163. The contractile effect of the muscles, in producing the varied +movements of the system, may be seen in the bending of the elbow. +The tendon of one extremity of the muscle is attached to the +shoulder-bone, which acts as a fixed point; the tendon of the +other extremity is attached to one of the bones of the fore-arm. When +the swell of the muscle contracts, or shortens, its two extremities +approach nearer each other, and by the approximation of the +terminal extremities of the muscle, the joint at the elbow bends. +On this principle, all the joints of the system are moved. This is +illustrated by fig. 45. + + -=-=-=-=-=-=-=-=-=-=-=-= + +161-172. _Give the physiology of the muscles._ 161. What are some of +the influences exerted by the muscles on the system? 162. What is +peculiar to muscular fibres? How is this illustrated? 163. Explain how +the movements of the system are effected by the contraction of the +muscles. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 45. A representation of the manner in which all of +the joints of the body are moved. 1, The bone of the arm above the elbow. +2, One of the bones below the elbow. 3, The muscle that bends the elbow. +This muscle is united, by a tendon, to the bone below the elbow, (4,) at +the other extremity, to the bone above the elbow, (5,) 6, The muscle that +extends the elbow. 7, Its attachment to the point of the elbow. 8, A +weight in the hand to be raised. The central part of the muscle 3 +contracts, and its two ends are brought nearer together. The bones below +the elbow are brought to the lines shown by 9, 10, 11. The weight is +raised in the direction of the curved line. When the muscle 6 contracts, +the muscle 3 relaxes and the fore-arm is extended.] + +_Experiments._ 1st. Clasp the arm midway between the shoulder and +elbow, with the thumb and fingers of the opposite hand. When the arm +is bent, the inside muscle will become hard and prominent, and its +tendon at the elbow rigid, while the muscle on the opposite side will +become flaccid. Extend the arm at the elbow, and the outside muscle +will swell and become firm, while the inside muscle and its tendon at +the elbow will be relaxed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 45. Give experiment 1st. + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. Clasp the fore-arm about three inches below the elbow, then open +and shut the fingers rapidly, and the swelling and relaxation of the +muscles on the opposite sides of the arms, alternating with each +other, will be felt, corresponding with the movement of the fingers. +While the fingers are bending, the inside muscles swell, and the +outside ones become flaccid; and, while the fingers are extending, the +inside muscles relax, and the outside ones swell. The alternate +swelling and relaxation of antagonist muscles may be felt in the +different movements of the limbs. + +164. Each fibre of the several muscles receives from the brain, through +the nervous filament appropriated to it, a certain influence, called +nervous fluid, or stimulus. It is this that induces contraction, while +the suspension of this stimulus causes relaxation of the fibres. By +this arrangement, the action of the muscular system, both as regards +duration and power, is, to a limited extent, under the control of the +mind. The more perfect the control, the better the education of the +muscular system; as is seen in the graceful, effective, and +well-educated movements of musicians, dancers, skaters, &c. + +165. The length of time which a muscle may remain contracted, varies. +The duration of the contraction of the voluntary muscles, in some +measure, is in an inverse ratio to its force. If a muscle has +contracted with violence, as when great effort is made to raise a +heavy weight, relaxation will follow sooner than when the contraction +has been less powerful, as in raising light bodies. + +166. The velocity of the muscular contraction depends on the will. +Many of the voluntary muscles in man contract with great rapidity, so +that he is enabled to utter distinctly fifteen hundred letters in a +minute; the pronunciation of each letter requiring both relaxation and +contraction of the same muscle, thus making three thousand actions in +one minute. But the contraction of the muscles of some of the inferior +animals surpasses in rapidity those of man. The race-horse, it is +said, has run a mile in a minute; and many birds of prey will probably +pass not less than a thousand miles daily. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give experiment 2d. 164. With what is each muscular fibre supplied? +What effect has this stimulus on the muscles? 165. how long does a +voluntary muscle remain contracted? 166. On what is the velocity of +muscular contraction dependent? How many letters may be pronounced in +a minute? + + -=-=-=-=-=-=-=-=-=-=-=-= + +167. The functions of the involuntary muscles are necessary the +digestion of food, the absorption and circulation of the nutritive +fluids. They could not be trusted with safety to the control of the +will, lest the passions or the indiscretions of the person should +continually avert those operations so necessary to health, and even to +life. The Divine Builder of this complicated machine has wisely +ordered that the muscles upon which these motions depend, shall act +under the impression of their proper stimulants, without the control +of the individual. + +168. Again, there are certain operations which could not be safely +intrusted to the absolute government of the voluntary muscles, or +entirely removed from their control. Thus life can be supported only a +few minutes without breathing; but it would be impossible to perform +the daily vocations of life if we were compelled to breathe at all +times, or at perfectly regular intervals. + +169. It has been observed that, among men of the same size, a wide +difference exists in their strength and activity--qualities which +depend upon the size and number of the nerves, the size and activity +of the brain, and the education, or training of the muscles. Men +having large nerves leading to the muscles, with the brain active, +and muscles well trained will perform feats of strength and agility, +that other men, of the same size, cannot effect. Rope-dancers, +harlequins, and other performers of feats, are persons thus +constituted. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How many contractions and relaxations of the same muscle? What is said +of the rapidity of muscular contractions in other animals? 167. When +are the involuntary muscles called into action? Why would it not have +been safe to trust these important operations to the exclusive control +of the will? 168. Give an instance where some of the muscles act under +the government of the will, conjoined with those that are involuntary. +169. On what does the difference in muscular activity and strength +depend? + + -=-=-=-=-=-=-=-=-=-=-=-= + +170. Persons with small muscles, and largely developed nervous +systems, will sometimes exhibit very great muscular power for a time; +but it will not be of long continuance, unless the brain is +functionally diseased, as in hysteria, delirium of fever, insanity, +&c. Men of large muscles and small nerves can never perform feats of +great strength; but they have the power of endurance, and are better +capacitated for continued labor. Thus we cannot judge of the ability +of persons to make exertions and continue them, by their stature +alone. Strength, and the power of endurance, are the result of a +combination of well-developed muscles, large nerves, and a full-sized, +healthy, and active brain. + +_Observation._ The muscles of fishes are large, and the nerves +distributed to them, comparatively small. The muscles of birds are +small, but their fibres are very compact. The nerves appropriated to +the muscles that are called into action in flying, are large as well +as numerous. + +171. The contractile portion of a muscle is, in general, at a distance +from the part to be moved. Thus the principal muscles that move the +fingers are situated upon the forearm; and when the limb is nearly or +quite extended, the angle formed by the part to be moved and the +contractile muscles is small. Again, the attachment of the muscles to +the part to be moved is near the joint that forms the fulcrum, (fig. +45.) By these arrangements there is a loss of power; but we are +compensated for this disadvantage by increased celerity of movement, +beauty of form, and adaptation of the limbs to the varied pursuits of +man. + + -=-=-=-=-=-=-=-=-=-=-=-= + +170. What is said of those persons who have small muscles and largely +developed nervous systems? Of those who have large muscles and small +nerves? Upon what do strength and the power of endurance depend? 171. +Why is there a loss of power in the action of the muscles? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ The muscle that bends the elbow acts at disadvantage, +and this is greatest when the arm is nearly or quite extended, as the +angle of action is then least. This disadvantage is further increased +by the attachment of the motive muscles near the joint. + +172. The number of muscles which are called into action in the +movements of the different joints, varies. The hinge-joints, as the +elbow, have two sets of muscles--one to bend the joint, the other to +extend it. The ball and socket joints, as the shoulder, are not +limited to mere flexion and extension. No joint in the system has the +range of movement that is possessed by that of the shoulder. By the +action of the muscles attached to the arm, it is not only carried +upward and forward, but forward and backward. Hence the arm may be +moved at any angle, by a combined action of its muscles. + +_Observation._ "Could we behold properly the muscular fibres in +operation, nothing, as a mere mechanical exhibition, can be conceived +more superb than the intricate and combined actions that must take +place during our most common movements. Look at a person running or +leaping, or watch the motions of the eye. How rapid, how delicate, how +complicated, and yet how accurate, are the motions required! Think of +the endurance of such a muscle as the heart, that can contract, with a +force equal to sixty pounds, seventy-five times every minute, for +eighty years together, without being weary." + +_Note._ It would be a profitable exercise for pupils to press their +fingers upon prominent muscles, and, at the same time, vigorously +contract them, not only to learn their situations, but their use; as +the one that bends the arm, 14, fig. 46. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is this illustrated? 172. Do all joints require the same number of +muscles, when called into action? How many are called into action in +the movement of the elbow? What is their office? What is said of the +movement of the ball and socket joint? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 46. An anterior view of the muscles of the body. 1. +The frontal swell of the occipito-frontalis. 2, The orbicularis +palpebrarum. 3, The levator labli superioris. 4, The zygomaticus major. +5, The zygomaticus minor. 6, The masseter. 7, The orbicularis oris. 8, +The depressor labli inferioris. 9. The platysma myodes. 10, The deltoid. +11, The pectoralis major. 12, The latissimus dorsi. 14, The biceps flexor +cubiti. 15, The triceps extensor cubiti. 16, The supinator radii longus. +18, The flexor carpi radialis longior. 19, The flexor communis digitorum. +20, The annular ligament. 21, The palmar fascia. 22, The obliquus +externus abdominis. 26, The psoas magnus. 27, The adductor longus. 28, +The sartorius. 29, The rectus femoris. 30, The vastus externus. 31, The +vastus internus. 32, The tendon patellae. 33, The gastrocnemius. 34, The +tibialis anticus. 36, The tendons of the extensor digitorum communis.] + +[Illustration: Fig. 47. A posterior view of the muscles of the body. 3, +The complexus. 4, The splenius. 5, The masseter. 6, The sterno-cleido +mastoideus. 7, The trapezius. 8, The deltoid. 10, The triceps extensor. +13, The tendinous portion of the triceps. 14, The anterior edge of the +triceps. 15, The supinator radii longus. 17, The extensor communis +digitorum. 18, The extensor ossis metacarpi pollicis. 19, The tendons of +the extensor communis digitorum. 20, The olecranon process of the ulna +and insertion of the triceps. 21, The extensor carpi ulnaris. 22, The +extensor communis digitorum. 24, The latissimus dorsi. 25, Its tendinous +origin. 26, The obliquus externus. 27, The gluteus medius. 28, The +gluteus magnus. 29, The biceps flexor cruris. 30, The semi-tendinosus. +31, 32, The gastrocnemius. 33, The tendo Achillis. + +_Practical Explanation._ The muscle 1, fig. 46, by its contraction, +raises the eyebrows. The muscle 2, fig. 46, closes the eyelids. The +muscle 3, fig. 46, elevates the upper lip. The muscles 4, 5, fig. 46, +elevate the angles of the mouth. The muscles 6, fig. 46, and 5, fig. 47, +bring the teeth together. The muscle 7, fig. 46, closes the mouth. The +muscle 8, fig. 46, depresses the lower lip. The muscles 9, fig. 46, and +6, fig. 47, bend the neck forward. The muscles 3, 4, fig. 47, elevate the +head and chin. The muscle 22, fig. 46, bends the body forward, and draws +the ribs downward. The muscle 11, fig. 46, brings the shoulder forward. +The muscle 7, fig. 47, draws the shoulder back. The muscles 10, fig. 46, +and 8, fig. 47, elevate the arm. The muscles 11, fig. 46, and 24, fig. +47, bring the arm to the side. The muscle 14, fig. 46, bends the arm at +the elbow. The muscle 10, fig. 47, extends the arm at the elbow. The +muscles 16, 18, fig. 46, bend the wrist and fingers. The muscle 19 bends +the fingers. The muscles 18, 21, 23, fig. 47, extend the wrist. The +muscle 23, fig. 47, extends the fingers. The muscles 26, 27, 28, fig. 46, +bend the lower limbs on the body, at the hip. The muscle 28, fig. 46, +draws one leg over the other, (the position of a tailor when sewing.) The +muscles 27, 28, fig. 47, extend the lower limbs on the body, at the hip. +The muscles 29, 30, 31, fig. 46, extend the leg at the knee. The muscles +29, 30, fig. 47, bend the leg at the knee. The muscles 34, 36, fig. 46, +bend the foot at the ankle, and extend the toes. The muscles 31, 32, 33, +fig. 47, extend the foot at the ankle.] + +_Note._ Let the anatomy and physiology of the muscular system be +reviewed, in form of topics, from figs 46, 47, or from the anatomical +outline plates No. 3 and 4. + + + + +CHAPTER X. + +HYGIENE OF THE MUSCLES + + +173. _The muscles should be used, in order that the size and strength +of these organs may be adequate to the demand made upon them._ It is a +law of the system that the action and power of an organ are +commensurate, to a certain extent, with the demand made upon it; and +it is a law of the muscular system that, whenever a muscle is called +into frequent use, its fibres increase in thickness within certain +limits, and become capable of acting with greater force; while, on the +contrary, the muscle that is little used decreases in size and power. + +_Illustrations._ 1st. The blacksmith uses and rests the muscles of his +arm when striking upon the anvil. They not only increase in size, but +become very firm and hard. + +2d. The student uses the muscles of the arm but little, in holding his +books and pen; they not only become small, but soft. + +3d. Let the student leave his books, and wield an iron sledge, and the +muscles of his arm will increase in size and firmness. On the other +hand, let the blacksmith assume the student's vocation, and the +muscles of his arm will become soft and less firm. + +174. _When the muscles are called into action, the flow of blood in +the arteries and veins is increased._ The increased flow of blood in +the arteries and veins, causes a more rapid deposition of the +particles of matter of which the muscles are composed. If the +exercise is adequate to the power of the system, the deposit of new +material will exceed in quantity the particles of matter removed, and +both the size and energy of the muscles are increased. But there is a +limit to the muscles becoming strong by labor. Sooner or later, man +will attain his growth or power; yet by judicious exercise, care, and +discreet management, the greatest power of the muscles may be +preserved until advanced age. + + -=-=-=-=-=-=-=-=-=-=-=-= + +173-211. _Give the hygiene of the muscles._ 173. What is necessary +that muscles may attain size and strength? Give a law of the muscular +system. Show this by practical illustrations. 174. Why do muscles +increase in size when exercised? + + -=-=-=-=-=-=-=-=-=-=-=-= + +175. _The muscles are lessened in size and diminished in power when +the exercise is continued so as to produce a feeling of exhaustion._ +The loss of material, in this instance, will exceed the deposition of +the atoms of matter. This is seen in the attenuated frames of +over-tasked domestic animals, as the horse. The same truth is +illustrated by the laborious agriculturist, who, in consequence of too +severe toil while gathering the products of the field, frequently +diminishes his weight several pounds in a few weeks. Exercise, either +for pleasure or profit, may fatigue, yet it should never be protracted +to languor or exhaustion, if the individual desires "a green old +age." + +176. _The same amount of exercise will not conduce to the health of +all individuals._ If riding or walking one mile causes slight fatigue, +this may be beneficial; while, by travelling two miles, the exhaustion +may be highly injurious. Exercise and labor should be adapted to the +strength of particular individuals. How little soever the strength, +that must be the measure of exertion. Any other rule would be fatal to +the hopes of invigorating the system, either by exercise or labor. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Is there a limit to the muscles becoming powerful by action? How may +the strength of muscles be kept until advanced age? 175. What is the +effect when exercise is continued until there is a feeling of +exhaustion? Give a practical illustration. What rule is mentioned in +regard to exercise? 176. Can all persons take the same amount of +exercise? What rule is given as to the amount of exercise? + + -=-=-=-=-=-=-=-=-=-=-=-= + +177. _Relaxation must follow contraction, or, in other words, rest +must follow exercise._ The necessity of relaxation, when a muscle has +been called into action, is seen in the example of a boy extending his +arm with a book in his hand, as a penalty. The boy can keep the arm +extended but a short time, make what effort he may. It is also seen in +the restlessness and feverish excitement that are evinced by persons +gazing on troops during days of review. The same is noted in shopping. +Such employments call into action the muscles that support the spinal +column in an erect position, and the languor or uneasiness is muscular +pain. The long-continued tension of a muscle enfeebles its action, and +eventually destroys its contractility. + +178. _In school, the small children, after sitting a short time, +become restless._ If their position be changed, their imperfectly +developed muscles will acquire tone, and will again support the spinal +column erect without pain. The necessity for frequent recesses in +school, is founded on the organic law of muscular action alternating +with rest. The younger and feebler pupils are, the greater the +necessity for frequent recesses. We would not have the teacher think +that one half of the time should be spent in recesses; or the mother, +that her daughter is going to school to play. But we do maintain that +recesses should be given, and that they should be short and frequent, +especially for small and feeble scholars. + +179. _Exhaustion is the inevitable result of continued muscular +contraction._ For example, let a lady ply the needle quickly for some +hours, and the muscles of the back and right arm will become +exhausted, which will be indicated by a sense of weariness in these +parts. A change of employment and position calls into action a +different set of muscles, and the exhausted organs are relieved. + + -=-=-=-=-=-=-=-=-=-=-=-= + +177. What is said of the contraction and relaxation of the muscles? +Give examples of the necessity of relaxing the muscles. 178. Why +should not small children be confined in one position for a long time? +What evils result from this practice? What class of pupils should have +recesses most frequently? 179. What effect has continued muscular +contraction? + + -=-=-=-=-=-=-=-=-=-=-=-= + +180. _Much more labor will be accomplished by taking time to relax the +exhausted muscles_, or by so changing the employment as to bring into +action a new set of muscles; the woodman thus relieves himself, by +sawing and splitting alternately. This principle applies to the labor +of the horse and ox; and it is also applicable to all kinds of +employment. With the invalid convalescing from fever, relapses result +from inattention to these laws. When a patient is recovering from +sickness, his physician should take care that his exercise be proper, +neither too much, too little, nor too long continued. + +181. _The muscles of growing youths will not endure so much exercise +or labor as those of mature men._ In youth a portion of the vital, or +nervous energy of the system, is expended upon the growth of the +organs of the body, while in the individual who has attained his +growth, this expenditure is not demanded; consequently severe labor or +exercise should not be imposed on growing children. + +_Observation._ In the campaigns of Napoleon Bonaparte, his army was +frequently recruited by mere boys. He complained to the French +government, because he was not supplied with men of mature years, as +the youths could not endure the exertion of his forced marches. + +182. _The muscles should be gradually called into action._ These +organs in action require more blood and nervous fluid than when at +rest. As the circulation of these fluids can only be increased in a +gradual manner, it follows, that, when the muscular system has been in +a state of rest, it should not suddenly be called into vigorous +action. On arising from a bed, lounge, or chair, the first movements +of the limbs should be slow, and then gradually increased. + +_Observation._ if a man has a certain amount of work to perform in +nine hours, and his muscles have been in a state of rest, he will do +it with less fatigue by performing half the amount of the labor in +five hours, and the remainder in four hours. The same principle should +be regarded in driving horses and other beasts of burden. + + -=-=-=-=-=-=-=-=-=-=-=-= + +180. How can the greatest amount of labor be secured with the least +exhaustion to the muscles? 181. Why should not severe labor be imposed +on growing children? 182. How should the muscles be called into +action? + + -=-=-=-=-=-=-=-=-=-=-=-= + +183. _The muscles should be rested gradually, when they have been +vigorously used._ If a person has been making great muscular exertion +in cutting wood, or any other employment, instead of sitting down to +rest, he should continue muscular action, for a short time, by some +moderate labor or amusement. + +184. _If the system has been heated by muscular action, and the skin +is covered with perspiration, avoid sitting down_ "to cool" in a +current of air; rather, put on more clothing, and continue to exercise +moderately. In instances when severe action of the muscles has been +endured, bathing and rubbing the skin of the limbs and joints that +have been used, are of much importance. The laboring agriculturist and +industrious mechanic, by reducing to practice this suggestion, would +thus prevent soreness of the muscles, and stiffness of the joints. + +185. _The muscles should be abundantly supplied with pure blood._ This +state of the circulating fluid requires a healthy condition of the +digestive apparatus, and that the skin should be kept warm by proper +clothing, clean by bathing, and be acted upon by pure air and good +light; the movements of the ribs and diaphragm should be unrestricted, +and the lungs should have ample volume and be supplied with pure air. +In all instances, muscular power is greatest when the preceding +conditions exist, as the muscles are then stimulated by pure blood; +consequently, it is of practical importance to the mechanic, the +farmer, the man of leisure, and not less so to the ladies, to observe +these conditions, whatever vocation of life they pursue. + + -=-=-=-=-=-=-=-=-=-=-=-= + +183. How should the muscles be rested when they have been vigorously +used? 184. What precaution is given when the skin is covered with +perspiration? How may soreness of the muscles, consequent upon severe +action, be prevented? 185. Should the muscles be supplied with pure +blood? When is muscular power the greatest? + + -=-=-=-=-=-=-=-=-=-=-=-= + +186. _The muscles should be used in pure air._ The purer the air we +breathe, the more stimulating the blood supplied to the muscles, and +the longer they can be used in labor, walking, or sitting, without +fatigue and injury; hence the benefit derived in thoroughly +ventilating all inhabited rooms. For the same reason, if the air of +the sick-room is pure, the patient will sit up longer than when the +air is impure. + +_Observation._ It is a common remark that sick persons will sit up +longer when riding in a carriage, than in an easy chair in the room +where they have lain sick. In the one instance, they breathe pure air; +in the other, usually, a confined, impure air. + +187. _The muscles should be exercised in the light._ Light, +particularly that of the sun, exercises more or less influence on man +and the inferior animals as well as on plants. Both require the +stimulus of this agent. Shops occupied by mechanics, kitchens, and +sitting-rooms, should be well lighted, and situated on the sunny side +of the house. Cellar kitchens and underground shops should be avoided. +For similar reasons, students should take their exercise during the +day, rather than in the evening, and, as much as possible, laborers +should avoid night toil. + +_Illustrations._ Plants that grow in the shade, as under trees, or in +a dark cellar, are of lighter color and feebler than those that are +exposed to the light of the sun. Persons that dwell in dark rooms are +paler and less vigorous than those who inhabit apartments well +lighted, and exposed to the rays of the sun. + + -=-=-=-=-=-=-=-=-=-=-=-= + +186. Why should the muscles be used in pure air? Give a common +observation. 187. What effect has light on the muscular system? What +should the laborer avoid? Why should not students take their daily +exercise in the evening? How is the influence of solar light +illustrated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +188. _Exercise should be regular and frequent._ The system needs this +means of invigoration as regularly as it does new supplies of food. It +is no more correct that we devote several days to a _proper_ action of +the muscles, and then spend one day inactively, than it is to take a +_proper_ amount of food for several days, and then withdraw this +supply for a day. The industrious mechanic and the studious minister +suffer as surely from undue confinement as the improvident and +indolent. The evil consequences of neglect of exercise are gradual, +and steal slowly upon an individual. But sooner or later they are +manifested in muscular weakness, dyspepsia, and nervous irritability. + +_Observation._ The custom among farmers of enduring severe and undue +toil for several successive days, and then spending one or two days in +idleness to _rest_, is injudicious. It would be far better to do less +in a day, and continue the labor through the period devoted to +idleness, and then no rest will be demanded. + +189. _Every part of the muscular system should have its appropriate +share of exercise._ Some employments call into exercise the muscles of +the upper limbs, as shoe-making; others, the muscles of the lower +limbs; while some, the muscles of both upper and lower limbs, with +those of the trunk, as farming. In some kinds of exercise, the lower +limbs are mainly used, as in walking; in others, the upper limbs; and +again, the muscles of the trunk, together with those of the upper and +lower limbs, as in archery, quoits, playing ball. Those trades and +kinds of exercise are most salutary, in which all the muscles have +their due proportion of action, as this tends to develop and +strengthen them equally. Thus labor upon the farm and domestic +employment are superior as vocations, and archery, quoits, and +dancing, if the air is pure, among the pastimes. For sedentary +persons, that kind of exercise is best which calls into action the +greatest number of muscles. + + -=-=-=-=-=-=-=-=-=-=-=-= + +188. How should exercise be taken? What is said respecting irregular +exercise? Are the consequences of neglected exercise immediately +apparent? What practical observation is given? 189. Should every +muscle have its due amount of exercise? Mention some employments that +only call into action the muscles of the upper limbs. Those of the +lower limbs, those of the trunk and limbs. Mention, in the different +pastimes, what muscles are called into action. + + -=-=-=-=-=-=-=-=-=-=-=-= + +190. _The proper time for labor or exercise should be observed._ This +is modified by many circumstances. As a general rule, the morning, +when the air is pure and the ground dry, is better than the evening; +for then, the powers of the body are greatest. Severe exercise and +labor should be avoided immediately before or after eating a full +meal, for the energies of the system are then required to perform the +digestive function. For similar reasons, it is not an appropriate time +for energetic muscular action immediately before or after severe +mental toil, as the powers of the system are then concentrated upon +the brain.[6] + + [6] It appears to be a fact, that no two important organs can be + called into intense action at the same time, without injury to + both, as well as to the general system. This arises from the + circumstance that an organ, when in functional action, attracts + fluids (sanguineous and nervous) from other organs of the + system. Except in a few instances of high health in youth, the + power of the system is not adequate to supply more than one + organ in action with the appropriate fluids at the same time. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What kinds of exercise are best? 190. What rule is given respecting +the time for exercise? 191. Why do the muscles require sleep? What is +the effect of an inversion of the law of rest? + + -=-=-=-=-=-=-=-=-=-=-=-= + +191. _The muscles require sleep to restore their expended energies._ +Among the arrangements of creative wisdom, no one harmonizes with the +wants of the system more than the alternation of day and night. The +natural inclination of man to sleep, is in the stilly hour of night, +when all nature reposes, and to be in action during the light of day. +An inversion of this law of rest causes greater exhaustion of the +system than the same amount of exertion during daylight. This is +illustrated by the wearied and exhausted condition of watchers, +night-police, and other individuals who spend a part of the night in +some active business of life. + +192. _The muscles should not be compressed._ Compression prevents the +blood from passing to the muscles with freedom; consequently, they are +not supplied with material to renovate and promote their growth. +Again, pressure stimulates the lymphatics to action; and by the +increased activity of these vessels the muscles are attenuated. In the +case of a man with a fractured limb, the muscles are not only +enfeebled by inaction, but diminished in size by compression from the +dressing. Limbs enfeebled in this way will not recover their size, +tone, and strength, until the bandages are removed, and a proper +amount of exercise taken. + +193. The pressure of tight dresses, under the name of a "snug fit," +enfeebles the muscles of the back, and is a common cause of projecting +shoulders and curvature of the spinal column. Thus every appendage to +the dress of ladies which prevents free motion of the muscles of the +chest and spinal column, weakens the muscles thus restrained, and not +only prevents the proper expansion of the lungs, but, by weakening the +muscles which sustain the spine, induces curvature and disease. +Whalebone, wood, steel, and every other unyielding substance, should +be banished from the toilet, as enemies of the human race. + +194. _The mind exerts a great influence upon the tone and contractile +energy of the muscular system._ A person acting under a healthy mental +stimulus will make exertion with less fatigue than he would without +this incentive. For this reason, a sportsman will pursue his game +miles without fatigue, while his attendant, not having any mental +stimulus, will become weary. Again, if the sportsman spends some hours +in pursuit of his favorite game without success, a feeling of languor +creeps over him; but while he is thus fatigued and dispirited, let him +catch a glimpse of the game,--his wearied feelings are immediately +dissipated, and he presses on with renewed energy and recruited +strength. + + -=-=-=-=-=-=-=-=-=-=-=-= + +192. Why should not the muscles be compressed? 193. What is the effect +of tight clothing upon the muscles? 194. What is said of the influence +of the mind upon muscular activity? Give an illustration of mental +stimulus cooperating with muscular activity in the case of a +sportsman. + + -=-=-=-=-=-=-=-=-=-=-=-= + +195. This principle was well illustrated in the retreat from Russia of +the defeated and dispirited French army. When no enemy was near, +they had hardly strength sufficient to carry their arms; but no +sooner did they hear the report of the Russian guns, than new life +seemed to pervade them, and they wielded their weapons powerfully +until the foe was repulsed, then there was a relapse to weakness, and +prostration followed. It is thus with the invalid when riding for +his health;--relate an anecdote, or excite this mental stimulus by +agreeable conversation, and much benefit will accrue from the ride +to the debilitated person. So it is in the daily vocations of +life; if the mind have some incentive, the tiresomeness of labor +will be greatly diminished. Let an air of cheerfulness ever pervade +our every employment, and, like music, "it sweetens toil." + +196. Facts illustrative of the inutility of calling the muscles into +action, without the cooperation of the mind, are seen in the +spiritless aspect of many of our boarding school processions, when a +walk is taken merely for exercise, without having in view any +attainable object. But present to the mind a botanical or geological +excursion, and the saunter will be exchanged for the elastic step, the +inanimate appearance for the bright eye and glowing cheek. The +difference is, simply, that, in the former case, the muscles are +obliged to work without that full nervous impulse so essential to +their energetic action; and that, in the latter, the nervous influence +is in full and harmonious operation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +195. Give an illustration of mental stimulus cooperating with muscular +activity in the case of the dispirited French army in their retreat +from Russia. How can a union of mental impulse and muscular action be +beneficial to an invalid? Does this same principle apply to those who +labor? 196. Give an instance of the different effects produced by the +absence and presence of the mental stimulus. + + -=-=-=-=-=-=-=-=-=-=-=-= + +197. It must not, however, be supposed that a walk simply for the sake +of exercise can never be beneficial. Every one, unless prevented by +disease, should consider it a duty to take exercise every day in the +open air; if possible, let it be had in combination with harmonious +mental exhilaration; if not, let a walk, in an erect position, be made +so brisk as to produce rapid respiration and circulation of the blood, +and in a dress that shall not interfere with free motions of the arms +and free expansion of the chest. + +_Observation._ The advantages of combining harmonious mental +excitement, with muscular activity, is thus given by Dr. Armstrong:-- + + "_In whate'er you sweat, + Indulge your taste._ Some love the manly toils + The tennis some, and some the graceful dance; + Others, more hardy, range the purple heath + Or naked stubble, where, from field to field, + The sounding covies urge their lab'ring flight, + Eager amid the rising cloud to pour + The gun's unerring thunder; and there are + Whom still the mead of the green archer charm. + _He chooses best whose labor entertains + His vacant fancy most; the toil you hate + Fatigues you soon, and scarce improves your limbs._" + + -=-=-=-=-=-=-=-=-=-=-=-= + +197. May not a walk, simply as an exercise, be beneficial? What is +preferred? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XI. + +HYGIENE OF THE MUSCLES, CONTINUED. + + +198. _The erect attitude lessens the exhaustion of the muscles._ A +person whose position is erect will stand longer, walk further, and +perform more labor, than an individual whose position is stooping, but +equal in all other respects. The manly port in an erect attitude, +depends chiefly upon the action of the muscles of the back; and it +follows that the fewer the muscles in a state of tension, the less the +draught upon the nervous system, and the less its exhaustion. Another +advantage which attends the erect position is, the trunk and head are +balanced upon the bones and cartilages of the spinal column. If the +body slightly incline forward, the muscles attached to the posterior +side of the spine, by a gentle contraction, will bring it to the +perpendicular, and even incline it backward. This is immediately +removed by a slight contraction of the muscles upon the anterior side +of the spinal column. + +199. In the erect position, there is a constant slight oscillation +of the body backward and forward, like the movement of a pendulum; +while, in the stooping posture, the muscles on the posterior side +of the spinal column are kept in a state of continued tension and +contraction, to prevent the body from falling forward. This enfeebles +the muscles of the back, and exhausts the nervous energy, while the +erect position favors their development and power, because there is +an alternate contraction and relaxation of the muscles. Again, in the +stooping position, the lower limbs are curved at the knee. In this +attitude, there is a constant tension of the muscles of the lower +extremities, which produces muscular exhaustion. + + -=-=-=-=-=-=-=-=-=-=-=-= + +198. Why will a person who stands erect walk further, and perform more +labor, than if he assumed the stooping posture? 199. Why are the +muscles of the back so soon exhausted in the stooping position? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 48. 1, A perpendicular line from the centre of the +feet to the upper extremity of the spinal column, where the head rests. +2, 2, 2, The spinal column, with its three natural curves. Here the head +and body are balanced upon the spinal column and joints of the lower +extremities, so that the muscles are not kept in a state of tension. This +erect position of the body and head is always accompanied with straight +lower limbs.] + +[Illustration: Fig. 49. 1, A perpendicular line from the centre of the +feet. 2, Represents the unnatural curved spinal column, and its relative +position to the perpendicular, 1. The lower limbs are curved at the knee, +and the body is stooping forward. While standing in this position, the +muscles of the lower limbs and back are in continued tension, which +exhausts and weakens them.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is represented by figs. 48 and 49? + + -=-=-=-=-=-=-=-=-=-=-=-= + +200. When it is necessary to call into action a part of the muscles of +the system in the performance of any duty, as those of the lower limbs +in walking, if the muscles of other parts are in a state of inaction, +the influence of the nervous system can be determined in an undivided +manner upon those parts of the lower limbs in action; hence they will +not so soon become wearied or exhausted, as when this influence is +divided between a greater number of muscles. In performing any labor, +as in speaking, reading, singing, mowing, sewing, &c., there will be +less exhaustion, and the effort can be longer maintained in the erect +position of the body and head, than in a stooping attitude. + +_Experiment._ Hold in each hand a pail of water or equal weights, in a +stooping posture, as long as it can be done without much suffering and +injury. Again, when the muscular pain has ceased, hold the same pails +of water, for the same length of time, in an erect posture, and note +the difference in the fatigue of the muscles. + +201. If the stooping posture is acquired in youth, we are quite +certain of seeing the deformed shoulders in old age. Hence the +importance of duly exercising the muscles of the back, for when they +are properly developed, the child can and will stand erect. In this +attitude, the shoulders will be thrown back, and the chest will become +broad and full. + +202. Pupils, while standing during recitations, often inadvertently +assume the attitude represented by fig. 49, and it is the duty of +teachers to correct this position when assumed. When a child or adult +has contracted a habit of stooping, and has become round-shouldered, +it can be measurably, and generally, wholly, remedied by moderate and +repeated efforts to bring the shoulders back, and the spinal column in +an erect position. This deformity can and should be remedied in our +schools. It may take months to accomplish the desired end, yet it can +be done as well under the direction of the kind instructor, as under +the stern, military drill sergeant, who never fails to correct this +deformity among his raw recruits. + + -=-=-=-=-=-=-=-=-=-=-=-= + +200. What suggestion when it is necessary to call into action a part +of the muscular system? Give the experiment that illustrates this +principle. 201. Why should a child he taught to stand erect? 202. How +can round shoulders acquired by habit be remedied? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 50. A proper position in sitting.] + +203. _The child should be taught to sit erect when employed in study +or work._ This attitude favors a healthy action of the various organs +of the system, and conduces to beauty and symmetry of form. Scholars +are more or less inclined to lean forward and place the elbow on the +table or desk, for support and this is often done when their seats +are provided with backs. Where there is a predisposition to curvature +of the spine, no position is more unfavorable or more productive of +deformities than this; for it is usually continued in one direction, +and the apparent deformity it induces is a projection of the +shoulders. If the girl is so feeble that she cannot sit erect, as +represented by fig. 50, let her stand or recline on a couch; either is +preferable to the position represented by fig. 51. In furnishing +school-rooms, care should be taken that the desks are not so low as to +compel the pupils to lean forward in examining their books. + + -=-=-=-=-=-=-=-=-=-=-=-= + +203. Why should the erect attitude be assumed in sitting? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 51. An improper position in sitting.] + +204. _The muscles, when exhausted, cannot endure continued effort._ +When the energies of the muscular system have been expended by severe +and long-continued exercise, or the brain and nervous system +prostrated by protracted mental effort, the muscles are unfitted to +maintain the body erect in standing or sitting for a long time, as the +nervous system, in its exhausted state, cannot supply a sufficient +amount of its peculiar influence to maintain the supporting muscles of +the body and head in a state of contraction. Hence, a child or adult, +when much fatigued, should not be compelled to stand or sit erect in +one posture, but should be permitted to vary the position frequently, +as this rests and recruits both the muscular and the nervous system. + +205. _A slight relaxation of the muscles tends to prevent their +exhaustion._ In walking, dancing, and most of the mechanical +employments, there will be less fatigue, and the movements will be +more graceful, when the muscles are slightly relaxed. When riding in +cars or coaches, the system does not suffer so severely from the jar +if there is a slight relaxation of the muscles, as when they are in a +state of rigid contraction. + +_Experiments._ Attempt to bow with the muscles of the limbs and trunk +rigid, and there will be a stiff bending of the body only at the +hip-joint. On the other hand, attempt to bow with the muscles +moderately relaxed; the ankle, the knee, and the hip-joint will +slightly bend, accompanied with an easy and graceful curve of the +body. + +206. The muscles when relaxed, together with the yielding character of +the cartilage, and the porous structure of the ends of the bones that +form a joint, diffuse or deaden the force of jars, or shocks, in +stepping suddenly down stairs, or in falling from moderate heights. +Hence, in jumping or falling from a carriage, or any height, the shock +to the organs of the system may be obviated in the three following +ways: 1st. Let the muscles be relaxed, not rigid. 2d. Let the limbs be +bent at the ankle, knee, and hips; the head should be thrown slightly +forward, with the trunk a little stooping. 3d. Fall upon the toes, not +the heel. + + -=-=-=-=-=-=-=-=-=-=-=-= + +204. When are the muscles unfitted to maintain the system erect either +in standing or sitting? What is necessary when this condition of the +system exists? 205. Why should the muscular system be slightly relaxed +in walking, &c.? Give illustrative experiments. 206. What is the +reason that we do not feel the jar in falling from a moderate height? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Experiments._ Stand with the trunk and lower limbs firm, and the +muscles rigid; then jump a few inches perpendicularly to the floor, +and fall upon the heels. Again, slightly bend the limbs, jump a few +inches, and fall upon the toes, and the difference in the force of the +shock, to the brain and other organs, will be readily noticed. + +207. _The muscles require to be educated, or trained._ The power of +giving different intonations in reading, speaking, singing, the varied +and rapid executions in penmanship, and all mechanical or agricultural +employments, depend, in a measure, upon the education of the muscles. +In the first effort of muscular education, the contractions of the +muscular fibres are irregular and feeble, as may be seen when the +child begins to walk, or in the first efforts of penmanship. + +208. _Repetition of muscular action is necessary._ To render the +action of the muscles complete and effective, they must be called into +action repeatedly and at proper intervals. This education must be +continued until not only each muscle, but every fibre of the muscle, +is fully under the control of the will. In this way persons become +skilful in every employment. In training the muscles for effective +action, it is very important that correct movements be adopted at the +commencement. If this is neglected, the motions will be constrained +and improper, while power and skill will be lost. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is this shown by experiment? 207. Upon what do the different +intonations of sound or mechanical employments depend? Why are the +first efforts in educating the muscles indifferent or irregular? 208. +Why is repetition of muscular action necessary? Why is it important +that correct movements be adopted in the first efforts of muscular +education? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ If a boy, while learning to mow, is allowed to swing +his scythe in a stooping position, twisting his body at every sweep of +the scythe, he will never become an easy, efficient mower. Proper +instruction is as necessary in many of the agricultural branches as in +the varied mechanical employments. + +[Illustration: Fig. 52. An improper, but not an unusual position, when +writing.] + +[Illustration: Fig. 53. A proper position, when writing.] + +209. _Good penmanship requires properly trained muscles._ To a +deficient analysis of the movements of the arm, hand, and fingers, on +the part of teachers and pupils in penmanship, together with an +improper position in sitting, is to be ascribed the great want of +success in acquiring this art. The pen should be held loosely, and +when the proper position is attained, the scholar should make an +effort to imitate some definite copy as nearly as possible. The +movements of the fingers, hand, and arm, necessary to accomplish this, +should be made with ease and rapidity, striving, at each effort, to +imitate the copy more nearly. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is this illustrated? 209. Why have so many pupils failed in +acquiring good penmanship? + + -=-=-=-=-=-=-=-=-=-=-=-= + +210. When the arm, hand, and fingers are rigid, the large muscles, +that bend and extend these parts, are called into too intense action. +This requires of the small muscles, that produce the lateral +movements, which are essential to rapidity in writing, an effort which +they cannot make, or can with difficulty accomplish. + +_Experiment._ Vigorously extend the fingers by a violent and rigid +contraction of the muscles upon the lower part of the arm, and the +lateral movement which is seen in their separation cannot be made. But +gently extend the fingers, and their oblique movements are made with +freedom. + +211. An individual who is acquainted with the laws of health, whose +muscles are well trained, will perform a certain amount of labor with +less fatigue and waste to the system, than one who is ignorant of the +principles of hygiene, and whose muscles are imperfectly trained. +Hence the laboring poor have a deep interest in acquiring a knowledge +of practical physiology, as well as skill in their trade or vocation. +It is emphatically true to those who earn their bread by the "sweat of +their brow," that "knowledge is power." + + -=-=-=-=-=-=-=-=-=-=-=-= + +210. What is said of the lateral and oblique movements of the arm, +hand, and fingers in writing? How is this shown by experiment? 211. +Why is the study of physiology and hygiene of utility to the laborer? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XII. + +THE TEETH. + + +212. The teeth, in composition, nutrition, and growth, are different +from other bones of the body. They vary in number at different periods +of life, and, unlike other bones, they are exposed to the immediate +action of atmospheric air and foreign substances. The bones of the +system, generally, when fractured, unite; but there is never a +permanent union of a tooth when broken. + + +ANATOMY OF THE TEETH. + +213. The TEETH are attached to the upper and lower jaw-bone, by means +of bony sockets, called _al've-o-lar_ processes. These give great +solidity to the attachment of the teeth, and frequently render their +extraction difficult. The gums, by their fibrous, fleshy structure, +serve to fix the teeth more firmly in the jaw. + +_Observation._ When a _permanent_ tooth is extracted, these bony +processes are gradually absorbed, so that in advanced age there +remains only the jaw-bone covered by the lining membrane of the gum. +This accounts for the narrow jaw and falling in of the lips in old +age. Frequently, a piece of the alveolar process comes out with the +tooth when extracted, and the dentist has then the credit of "breaking +the jaw." No great injury results from the removal of the process in +this manner. + + -=-=-=-=-=-=-=-=-=-=-=-= + +212. What is said of the teeth? In what respect do they differ from +other bones of the body? 213-218. _Give the anatomy of the teeth._ +213. What confines the teeth in the jaw-bone? What becomes of the +socket when a tooth is removed? What effect has this absorption upon +the jaw and lips? + + -=-=-=-=-=-=-=-=-=-=-=-= + +214. The teeth are formed in the interior of the jaws, and within +_dent'al cap'sules_, (membranous pouches,) which are enclosed within +the substance of the bone, and present in their interior a fleshy bud, +or granule, from the surface of which exudes the ivory, or the bony +part of the tooth. In proportion as the tooth is formed, it rises in +the socket, which is developed simultaneously with the tooth, and +passes through the gum, and shows itself without. + +[Illustration: Fig. 54. 1, The body of the lower jaw. 2, Ramus, or branch +of the jaw, to which the muscles that move it are attached. 3, 3, The +processes which unite the lower jaw with the head. _i_, The middle and +lateral incisor tooth of one side. _b_, The bicuspid teeth. _c_, The +cuspids, or eye teeth. m, The three molar teeth. A, shows the relation of +the permanent to the temporary teeth.] + +215. The first set, which appears in infancy, is called _tem'po-ra-ry_, +or milk teeth. They are twenty in number; ten in each jaw. Between +six and fourteen years of age, the temporary teeth are removed, and the +second set appears, called _per'ma-nent_ teeth. They number +thirty-two, sixteen in each jaw. + + -=-=-=-=-=-=-=-=-=-=-=-= + +214. Where and how are the teeth formed? Explain fig. 54. 215. What +are the first set called? How many in each jaw? The second set? How +many in number? + + -=-=-=-=-=-=-=-=-=-=-=-= + +216. The four front teeth in each jaw are called _in-ci'sors_, +(cutting teeth;) the next tooth in each side, the _cus'pid_, (eye +tooth;) the next two, _bi-cus'pids_, (small grinders;) the next two, +_mo'lars_, (grinders.) The last one on each side of the jaw is called +a _wisdom tooth_, because it does not appear until a person is about +twenty years old. The incisors, cuspids, and bicuspids, have each but +one root. The molars of the upper jaw have three roots, while those of +the lower jaw have but two. + +[Illustration: Fig. 55. The permanent teeth of the upper and lower jaw. +_a_, _b_, The incisors. _c_, The cuspids. _d_, _e_, The bicuspids. _f_, +_g_, The molars, (double teeth.) _h_, The wisdom teeth.] + +_Observation._ The shape of the teeth in different species of animals +is adapted to the kind of food on which they subsist. Those animals +that feed exclusively on flesh, as the lion, have the cuspids, or +canine teeth, largely developed, and the molars have sharp cutting +points. Those animals that feed on grass and grain, as the horse and +the sheep, have their molar teeth more rounded and flat on the crown. +The human teeth are adapted to feed on fruits, grain, or flesh, as +they are less pointed than those of the cat, and more pointed than +those of the sheep. + + -=-=-=-=-=-=-=-=-=-=-=-= + +216. Give the names of the permanent teeth. What teeth have but one +root, or "fang"? How many roots have the molars of the upper jaw? Of +the lower jaw? What is said of the shape of the teeth in different +species of animals? + + -=-=-=-=-=-=-=-=-=-=-=-= + +217. The teeth are composed principally of two substances--the +_i'vo-ry_ and the _en-am'el_. The internal part of the tooth or the +ivory, is harder and more enduring than bone, and forms the body of +the tooth. The enamel is remarkable for its hardness, and varies +somewhat in color with the age, temperament, habits, and manner of +living of different individuals. When any part of the enamel is +destroyed, it is never regenerated. + +[Illustration: Fig. 56. A side view of the body and enamel of a front +tooth.] + +[Illustration: Fig. 57. A side view of a molar tooth. 1, The enamel. 2, +The body of the tooth. 3, The cavity in the crown of the tooth that +contains the pulp. 4, A nerve that spreads in the pulp of the tooth. 5, +An artery that ramifies in the pulp of the tooth.] + +218. Each tooth is divided into two parts, namely, _crown_ and _root_. +The crown is that part which protrudes from the jaw-bone and gum, and +is covered by the highly polished enamel. The root, or "fang," is +placed in the sockets of the jaw, and consists of bony matter. Through +this bony substance several small vessels pass, to aid in the growth +and also in the removal of the tooth. There are, beside these +vessels, small white cords passing to each tooth, called _nerves_. +(See fig. 57.) When these nerves are diseased, we have the toothache. + + -=-=-=-=-=-=-=-=-=-=-=-= + +217. Give the structure of the teeth. What is said of the enamel? 218. +Into how many parts are the teeth divided? Describe the crown. The +root. What vessels pass through the bony matter? What is their use? + + -=-=-=-=-=-=-=-=-=-=-=-= + + +PHYSIOLOGY OF THE TEETH. + +219. The use of the teeth is twofold. 1st. By the action of the +incisors the food is divided, while the molars grind or break down the +more solid portions of it. By these processes, the food is prepared to +pass more easily and rapidly into the stomach. + +220. In the mastication of food there are two movements of the lower +jaw--the action by which the teeth are brought together, and the +lateral motion. In the former, the food is cut or divided, the jaws +acting like shears. This movement is produced by the action of two +large muscles situated on each side of the head and face. + +_Observation._ The muscles attached to the lower jaw are of great +strength; by their action alone, some persons are enabled to bite the +hardest substances. By putting the fingers upon the side of the head +above and in front of the ears, and upon the face above the angle of +the jaw, while masticating food, the alternate swelling and relaxation +of these muscles will be clearly felt. + +221. The lateral, or grinding movement of the teeth, is produced by +the action of a strong muscle that is attached to the lower jaw on the +inside. + +_Observation._ Those animals that live solely on flesh, have only the +cutting, or shear-like movement of the jaws. Those that use +vegetables for food, have the grinding motion; while man has both the +cutting and grinding movement. + + -=-=-=-=-=-=-=-=-=-=-=-= + +219-222. _Give the physiology of the teeth._ 219. Give one of the +functions of the teeth. 220. How many movements of the lower jaw in +masticating food? What effect has the first movement upon the food? +How produced? What is the character of the masticating muscles? 221. +How is the grinding motion of the teeth produced? What is said of the +movements of the teeth in different animals? + + -=-=-=-=-=-=-=-=-=-=-=-= + +222. 2d. The teeth aid us in articulating with distinctness certain +letters and words. An individual who has lost his front teeth cannot +enunciate distinctly certain letters called dental. Again, as the +alveolar processes are removed by absorption soon after the removal of +the teeth, the lips and cheeks do not retain their former full +position, thus marring, in no slight degree, the symmetry of the lower +part of the face. Consequently, those simple observances that tend to +the preservation of the teeth are of great practical interest to all +persons. + + +HYGIENE OF THE TEETH. + +223. _To preserve the teeth, they must be kept clean._ After eating +food, they should be cleansed with a brush and water, or rubbed with a +piece of soft flannel, to prevent the _tartar_ collecting, and to +remove the pieces of food that may have lodged between them. +Toothpicks may be useful in removing any particles inaccessible to the +brush. They may be made of bone, ivory, or the common goose-quill. +Metallic toothpicks should not be used, as they injure the enamel. + +224. _The mouth should be cleansed with pure tepid water at night, as +well as in the morning_; after which the teeth should be brushed +upward and downward, both on the posterior and anterior surfaces. It +may be beneficial to use refined soap, once or twice every week, to +remove any corroding substance that may exist around the teeth; care +being taken to thoroughly rinse the mouth after its use. + +225. _Food or drink should not be taken into the mouth when very hot +or very cold._ Sudden changes of temperature will crack the enamel, +and finally produce decayed teeth. + + -=-=-=-=-=-=-=-=-=-=-=-= + +222. What is another use of the teeth? 223-232. _Give the hygiene of +the teeth._ 223. How can the teeth be preserved? By what means? 224. +How often should they be cleansed? 225. What is said of very hot or +cold drinks? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ On this account, smoking is pernicious, because the +teeth are subjected to an alternate inhalation of both cold and warm +air. + +226. _The temporary teeth should be removed as soon as they become +loose._ If a permanent tooth makes it appearance before the first is +removed, or has become loose, the milk tooth, although not loose, +should be removed without delay. This is necessary that the second set +of teeth may present a regular and beautiful appearance. + +227. _In general, when the permanent teeth are irregular, one or more +should be removed._ If the teeth are crowded and irregular, in +consequence of the jaw being narrow and short, or when they press so +hard upon each other as to injure the enamel, remove one or more to +prevent their looking unsightly, and in a few months the remaining +teeth, with a little care, will fill the spaces. + +_Observation._ When it is necessary to remove a tooth, apply to some +skilful operator. It requires as much skill and knowledge to extract +teeth _well_, as it does to amputate a limb; yet some persons, who +possess strong arms, will obtain a pair of forceps, or a tooth-key, +and hang out the sign of "surgeon-dentist," although ignorant of the +principles that should guide them. + +228. _It is not always necessary to have teeth extracted when they +ache._ The nerve, or the investing membrane of the root, may be +diseased, and the tooth still be sound. In such instances, the tooth +should not be extracted, but the diseased condition may be remedied by +proper medication. There are many sound teeth, that become painful, as +already mentioned, which are unnecessarily removed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Why is smoking injurious to the teeth? 226. What remark respecting the +temporary teeth? 227. What remarks respecting the permanent teeth? Do +those persons that extract teeth require skill as well as knowledge? +228. Why should not teeth be extracted at all times when they are +painful? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ Dr. H. M., of Belfast, Me., related to me that an +individual in that vicinity had his teeth, (all of them sound,) on one +side of the lower jaw, extracted by an ignoramus of a "tooth-puller," +and this without any relief from pain. The disease was tic douloureux, +which was relieved by Dr. M. + +229. _The preservation of the teeth requires that they be frequently +examined._ When a part of the enamel is removed, and a small portion +of the body of the tooth has become carious, in many instances such +teeth may be preserved from further decay by having them filled or +"plugged" with _gold foil_. All amalgams, pastes, and cheap patent +articles for filling, should be avoided, if you would preserve both +the teeth and the general health. + +230. The practice of cracking nuts with the teeth, or of lifting heavy +bodies, and the constant habit of biting thread, should be avoided, as +they finally destroy the enamel. + +231. _All acidulated drinks and mineral waters, that "set the teeth on +edge," are injurious._ All tooth-powders and washes that contain any +article that is acid, corrosive, or grinding, should be banished from +the toilet. Tobacco is not a preservative of the teeth. It contains +"grit," which wears away the enamel; beside, when chewed, it +debilitates the vessels of the gums, turns the teeth yellow, and +renders the breath and the appearance of the mouth disagreeable. + +232. Healthy persons have generally sound teeth, while feeble persons +have decayed teeth. For this reason, we should try to learn and +practise the few simple rules that promote health. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give an illustration of the removal of sound teeth. 229. How may +decaying teeth be preserved? What should be avoided in the filling of +teeth? 230. What practices should also be avoided? 231. What is said +of acidulated drinks? What effect has the chewing of tobacco upon the +teeth? 232. What is one reason for preserving health? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XIII. + +THE DIGESTIVE ORGANS. + + +233. From the earliest existence of the human system to the last ray +of life, change is impressed upon it by the Giver of this curious +fabric. New atoms of matter are deposited, while the old and now +useless particles are constantly removed. The material necessary to +sustain the growth of the body in early life, and also to repair the +waste that is unceasing to animal existence, is the food we eat. + +234. Food, animal or vegetable, contains most of the elements of the +different tissues of the system, yet it must undergo certain essential +alterations before it can become a part of the body. The first change +is effected by the action of the _Digestive Organs_. + + +ANATOMY OF THE DIGESTIVE ORGANS + +235. The DIGESTIVE ORGANS are the _Mouth_, _Teeth_,[7] _Sal'i-va-ry +Glands_, _Phar'ynx_, _OE-soph'a-gus_, (gullet,) _Stom'ach_, +_In-tes'tines_, (bowels,) _Lac'te-als_, (milk, or chyle vessels,) +_Tho-rac'ic Duct_, _Liv'er_, and the _Pan'cre-as_, (sweetbread.) + + [7] See Chapter XII. + + -=-=-=-=-=-=-=-=-=-=-=-= + +233. What is impressed upon the human system from its earliest +existence? What maintains this change? 234. Has animal or vegetable +food any resemblance to the different tissues of which it finally +forms a part? By what organs is the first change in the food effected? +235-258. _Give the anatomy of the digestive organs._ 235. Name them. +236. Describe the mouth. + + -=-=-=-=-=-=-=-=-=-=-=-= + +MOUTH is an irregular cavity, which contains the instruments of +mastication and the organs of taste. It is bounded in front by the +lips; on each side by the internal surface of the cheeks; above, by +the _hard palate_ (roof of the mouth) and teeth of the upper jaw; +below, by the tongue and teeth of the lower jaw; behind, it is +continuous with the pharynx, but is separated from it by a kind of +movable curtain, called the _soft palate_. This may be elevated or +depressed, so as to close the passage or leave it free. + +237. The SALIVARY GLANDS are six in number; three on each side of the +jaw. They are called the _pa-rot'id_, the _sub-max'il-la-ry_ and the +_sub-lin'gual_. + +[Illustration: Fig. 58. A view of the salivary glands in their proper +situations. 1, The parotid gland. 2, Its duct. 3, The submaxillary gland. +4, Its duct. 5, The sublingual gland, brought to view by the removal of a +section of the lower jaw.] + +238. The PAROTID GLAND, the largest, is situated in front of the +external ear, and behind the angle of the jaw. A duct (Steno's) from +this gland opens into the mouth, opposite the second molar tooth of +the upper jaw. + + -=-=-=-=-=-=-=-=-=-=-=-= + +237. How many glands about the mouth? Give their names. What does fig. +58 represent? 238. Describe the parotid gland. + + -=-=-=-=-=-=-=-=-=-=-=-= + +239. The SUBMAXILLARY GLAND is situated within the lower jaw, anterior +to its angle. Its excretory duct (Wharton's) opens into the mouth by +the side of the _frae'num lin'guae_, (bridle of the tongue.) + +240. The _SUBLINGUAL GLAND_ is elongated and flattened, and situated +beneath the mucous membrane of the floor of the mouth, on each side of +the fraenum linguae. It has seven or eight small ducts, which open into +the mouth by the side of the bridle of the tongue. + +_Observation._ In the "mumps," the parotid gland is diseased. The +swelling under the tongue called the "frog" is a disease of the +sublingual gland. + +[Illustration: Fig. 59. A side view of the face, oesophagus, and trachea. +1, The trachea (wind pipe.) 2, The larynx. 3, The oesophagus. 4, 4, 4, +The muscles of the upper portion of the oesophagus forming the pharynx. +5, The muscle of the cheek. 6, The muscle that surrounds, the mouth. 7, +The muscle that forms the floor of the mouth.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +239. The submaxillary. 240. The sublingual. What observation +respecting these glands? What does fig. 59 represent? + + -=-=-=-=-=-=-=-=-=-=-=-= + +241. The PHARYNX is a membranous sac, situated upon the upper portion +of the spinal column. It extends from the base of the skull to the top +of the _tra'che-a_, (windpipe,) and is continuous with the oesophagus. +From the pharynx are four passages; one opens upward and forward to +the nose, the second leads forward to the mouth, the third downward to +the trachea and lungs, the fourth downward and backward to the +stomach. + +242. The OESOPHAGUS is a large membranous tube that extends behind the +trachea, the heart, and lungs, pierces the diaphragm, and terminates +in the stomach. It is composed of two membranes--an internal, or +mucous, and a muscular coat. The latter is composed of two sets of +fibres; one extends lengthwise, the other is arranged in circular +bands. + +243. The STOMACH is situated in the left side of the abdomen, +immediately below and in contact with the diaphragm. It has two +openings; one connected with the oesophagus, called the _car'di-ac_ +orifice; the other connected with the upper portion of the small +intestine, called the _py-lor'ic_ orifice. It is composed of three +coats, or membranes. The exterior or serous coat is very tough and +strong, and invests every part of this important organ. The middle, or +muscular coat is composed of two layers of muscular fibres, one set of +which is arranged longitudinally, the other circularly. The interior +coat is called the mucous, and is arranged in _ru'gae_, (folds.) The +stomach is provided with a multitude of small glands, in which is +secreted the gastric fluid. + +_Illustration._ The three coats of the stomach anatomically resemble +tripe, which is a preparation of the largest stomach of the cow or ox. +The outer coat is smooth and highly polished. The middle coat is +composed of minute threads, which are arranged in two layers. The +fibres of these layers cross each other. The inner coat is soft, and +presents many folds, usually named "the honey-comb." + + -=-=-=-=-=-=-=-=-=-=-=-= + +241. Describe the pharynx and the passages leading from it. 242. Give +the structure of the oesophagus. 243. Where is the stomach situated? +How many coats has it? Describe them. What article prepared for food +does the stomach resemble? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 60. The inner surface of the stomach and duodenum. 1, +The lower portion of the oesophagus. 2, The opening through which the +food is passed into the stomach. 8, The stomach. 9, The opening through +which the food passes out of the stomach into the duodenum, or upper +portion of the small intestine. 10, 11, 14, The duodenum 12, 13, Ducts +through which the bile and pancreatic fluid pass into it. _a_, _b_, _c_, +The three coats of the stomach.] + +244. The INTESTINES, or alimentary canal, are divided into two +parts--the _small_ and _large_. The small intestine is about +twenty-five feet in length, and is divided into three portions, +namely, the _Du-o-de'num_, the _Je-ju'num_, and the _Il'e-um_. The +large intestine is about five feet in length, and is divided into +three parts, namely, the _Cae'cum_, the _Co'lon_, and the _Rec'tum_. +(Appendix D.) + +245. The DUODENUM is somewhat larger than the rest of the small +intestine, and has received its name from being in length about the +breadth of twelve fingers. It commences at the pylorus, and ascends +obliquely backward to the under surface of the liver. It then descends +perpendicularly in front of the right kidney, and passes transversely +across the lower portion of the spinal column, behind the colon, and +terminates in the jejunum. The ducts from the liver and pancreas open +into the perpendicular portion, about six inches from the stomach. + + -=-=-=-=-=-=-=-=-=-=-=-= + +244. Explain fig. 60. What is the length of the small intestine, and +how is it divided? What is the length of the large intestine? Give its +divisions. 245. Describe the duodenum. + + -=-=-=-=-=-=-=-=-=-=-=-= + +246. The JEJUNUM is continuous with the duodenum. It is thicker than +the rest of the small intestine, and has a pinkish tinge. + +247. The ILEUM is smaller, and thinner in texture, and somewhat paler, +than the jejunum. There is no mark to distinguish the termination of +the one or the commencement of the other. The ileum terminates near +the right haunch-bone, by a valvular opening into the colon at an +obtuse angle. This arrangement prevents the passing of substances from +the colon into the ileum. The jejunum and ileum are surrounded above +and at the sides by the colon. + +248. The small intestine, like the stomach, has three coats. The +inner, or mucous coat is thrown into folds, or valves. In consequence +of this valvular arrangement, the mucous membrane is more extensive +than the other tissues, and gives a greater extent of surface with +which the aliment comes in contact. There are imbedded under this +membrane an immense number of minute glands, and it has a great number +of piles, like those upon velvet. For this reason, this membrane is +sometimes called the _vil'lous_ coat. + +249. The CAECUM is the blind pouch, or cul-de-sac, at the commencement +of the large intestine. Attached to its extremity is the _ap-pend'ix +verm-i-form'is_, (a long, worm-shaped tube.) It is from one to six +inches in length, and of the size of a goose-quill. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What important ducts open into it? 246. Describe the jejunum. 247. The +ileum. 248. What is said of the coats of the intestines? Why is the +mucous membrane sometimes called the villous coat? 249. Describe the +caecum. + + -=-=-=-=-=-=-=-=-=-=-=-= + +250. The COLON is divided into three parts--the _ascending_, +_transverse_, and _descending_. The ascending colon passes upward from +the right haunch-bone to the under surface of the liver. It then bends +inward, and crosses the upper part of the abdomen, below the liver and +stomach, to the left side under the name of the transverse colon. At +the left side, it turns, and descends to the left haunch-bone, and is +called the descending colon. Here it makes a peculiar curve upon +itself, which is called the _sig'moid flex'ure_. + +[Illustration: Fig. 61. 1, 1, The duodenum. 2, 2, The small intestine. 3, +The junction of the small intestine with the colon. 4, The appendix +vermiformis. 5, The caecum. 6, The ascending colon. 7, The transverse +colon. 8, The descending colon. 9, The sigmoid flexure of the colon. 10, +The rectum.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +250. Describe the course of the divisions of the colon. Explain fig. +61. + + -=-=-=-=-=-=-=-=-=-=-=-= + +251. The RECTUM is the termination of the large intestine. The large +intestine has three coats, like the stomach and small intestine. The +longitudinal fibres of the muscular coat are collected into three +bands. These bands are nearly one half shorter than the intestine, and +give it a sacculated appearance, which is characteristic of the caecum +and colon. + +252. The LACTEALS are minute vessels, which commence in the villi, +upon the mucous surface of the small intestine. From the intestine +they pass between the membranes of the _mes'en-ter-y_ to small glands, +which they enter. The first range of glands collects many small +vessels, and transmits a few larger branches to a second range of +glands; and, finally, after passing through several successive ranges +of these glandular bodies, the lacteals, diminished in number and +increased in size, proceed to the enlarged portion of the thoracic +duct, into which they open. They are most numerous in the upper +portion of the small intestine. + +253. The THORACIC DUCT commences in the abdomen, by a considerable +dilatation, which is situated in front of the lower portion of the +spinal column. From this point, it passes through the diaphragm, and +ascends to the lower part of the neck. In its ascent, it lies anterior +to the spine, and by the side of the aorta and oesophagus. At the +lower part of the neck, it makes a sudden turn downward and forward, +and terminates by opening into a large vein which passes to the heart. +The thoracic duct is equal in diameter to a goose-quill, and, at its +termination, is provided with a pair of semilunar valves, which +prevent the admission of venous blood into its cylinder. + + -=-=-=-=-=-=-=-=-=-=-=-= + +251. What is said of the arrangement of the fibres of the muscular +coat of the large intestine? 252. What are the lacteals? Give their +course from the mucous coat of the intestine to the thoracic duct. +253. Describe the course of the thoracic duct. How is the venous blood +prevented from passing into this duct? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 62. A portion of the small intestine, lacteal +vessels, mesenteric glands, and thoracic duct. 1, The intestine. 2, 3, 4, +Mesenteric glands, through which the lacteals pass to the thoracic duct. +5, 6, The thoracic duct. 7, The point in the neck where it turns down to +enter the vein at 8. 9, 10, The aorta. 11, 12, Vessels of the neck. 13, +14, 15, The large veins that convey the blood and chyle to the heart. 16, +17, The spinal column. 18, The diaphragm, (midriff.)] + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 62. What is said respecting the mesenteric glands? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ The mesenteric glands, which are situated between two +layers of serous membrane (mesentery) that connects the small +intestine with the spinal column, occasionally become diseased in +childhood, and prevent the chyle from passing to the thoracic duct. +Children thus affected have a voracious appetite, and at the same time +are becoming more and more emaciated. The disease is called mesenteric +consumption. + +254. The LIVER, a gland appended to the alimentary canal, is the +largest organ in the system, and weighs about four pounds. It is +situated in the right side, below the diaphragm, and is composed of +several lobes. Its upper surface is convex; its under, concave. This +organ is retained in its place by several ligaments. It performs the +double office of separating impurities from the venous blood, and of +secreting a fluid (bile) necessary to chylification. On the under +surface of the liver is a membranous sac, called the _gall-cyst_, +which is generally considered as a reservoir for the bile. + +[Illustration: Fig. 63. The under surface of the liver. 1, The right +lobe. 2, The left. 3, 4, Smaller lobes. 10, The gall-bladder, or cyst, +lodged in its depression. 17, The notch on the posterior border, for the +spinal column.] + +_Observation._ A good idea of the liver and intestines can be obtained +by examining these parts of a pig. In this animal, the sacs, or +pouches, of the large intestine are well defined. + +255. The PANCREAS is a long, flattened gland, analogous to the +salivary glands. It is about six inches in length, weighs three or +four ounces, and is situated transversely across the posterior wall of +the abdomen, behind the stomach. A duct from this organ opens into the +duodenum. + + -=-=-=-=-=-=-=-=-=-=-=-= + +254. Describe the liver. 255. What is said of the pancreas? + + -=-=-=-=-=-=-=-=-=-=-=-= + +256. The SPLEEN, (milt,) so called because the ancients supposed it to +be the seat of melancholy, is an oblong, flattened organ, situated in +the left side, in contact with the diaphragm, stomach, and the +pancreas. It is of a dark, bluish color, and is abundantly supplied +with blood, but has no duct which serves as an outlet for any +secretion. Its use is not well determined. + +[Illustration: Fig. 64. The pancreas with its duct, through which the +pancreatic secretion passes into the duodenum.] + +257. The OMENTUM (caul) consists of four layers of the serous +membrane, which descends from the stomach and transverse colon. A +quantity of adipose matter is deposited around its vessels, which +ramify through its structure. Its function is twofold in the animal +economy. 1st. It protects the intestines from cold. 2d. It facilitates +the movements of the intestines upon each other during their +vermicular, or worm-like action. + +258. Every part of the digestive apparatus is supplied with arteries, +veins, lymphatics, and nervous filaments, from the ganglionic system +of nerves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +256. Why is the spleen so called? What is peculiar to this organ? 257. +Of what is the omentum composed? What is its use? 258. With what is +every part of the digestive apparatus supplied? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XIV. + +PHYSIOLOGY OF THE DIGESTIVE ORGANS. + + +259. Substances received into the stomach as food, must necessarily +undergo many changes before they are fitted to form part of the animal +body. The solid portions are reduced to a fluid state, and those parts +that will nourish the body are separated from the waste material. + +260. The first preparation of food for admission into the system, +consists in its proper mastication. The lips in front, the cheeks upon +the side, the soft palate, by closing down upon the base of the +tongue, retain the food in the mouth, while it is subjected to the; +process of _mas-ti-ca'tion_, (chewing.) The tongue rolls the mass +around, and keeps it between the teeth, while they divide the food to +a fineness suitable for the stomach. + +261. While the food is in process of mastication, there is incorporated +with it a considerable amount of _sa-li'va_, (spittle.) This fluid is +furnished by the salivary glands, situated in the vicinity of the +mouth. The saliva moistens and softens the food, so that, when carried +into the pharynx. it is passed, with ease, through the oesophagus into the +stomach. + +262. When the food has been properly masticated, (and in rapid eaters +when it is not,) the soft palate is raised from the base of the tongue +backward, so as to close the posterior opening through the nostrils. +By a movement of the muscles of the tongue, cheeks, and floor of the +mouth, simultaneous with that of the soft palate, the food is pressed +into the upper part of the pharynx. + + -=-=-=-=-=-=-=-=-=-=-=-= + +259-272. _Give the physiology of the digestive organs._ 259. What is +necessary before food can nourish the body? 260. Describe how +mastication is performed. 261. Of what use is the saliva in the +process of mastication? 262. How is the food pressed into the +pharynx? + + -=-=-=-=-=-=-=-=-=-=-=-= + +263. When in the pharynx, the food and drink are prevented from +passing into the trachea by a simple valve-like arrangement, called +the _ep-i-glot'tis_. The ordinary position of this little organ is +perpendicular, so as not to obstruct the passage of air into the +lungs; but in the act of swallowing, it is brought directly over the +opening of the trachea, called the _glot'tis_. The food, being forced +backward, passes rapidly over the epiglottis into the oesophagus, +where the circular band of muscular fibres above, contracts and forces +the food to the next lower band. Each band relaxes and contracts +successively, and thus presses the alimentary ball downward and onward +to the stomach.[8] + + [8] The process of deglutition may be comprehended by analyzing the + operation of swallowing food or saliva. + +_Observation._ If air is inhaled when the food or drink is passing +over the glottis, some portions of it may be carried into the larynx +or trachea. This produces violent spasmodic coughing, and most +generally occurs when an attempt is made to speak while masticating +food; therefore, never talk when the mouth contains food. + + -=-=-=-=-=-=-=-=-=-=-=-= + +263. When the food is in the pharynx, how is it prevented from passing +into the trachea, or windpipe? Describe how it is passed into the +stomach? Give the observation. 264. Describe how the food in the +stomach is converted into chyme. + + -=-=-=-=-=-=-=-=-=-=-=-= + +264. When the food reaches the stomach, the gastric glands are excited +to action, and they secrete a powerful solvent, called gastric juice. +The presence of food in the stomach also increases a contractile +action of the muscular coat, by which the position of the food is +changed from one part of this cavity to another. Thus the aliment is +brought in contact with the mucous membrane, and each portion of it +becomes saturated with gastric juice, by which it is softened, or +dissolved into a pulpy homogeneous mass, of a creamy consistence, +called _Chyme_. The food is not all converted into chyme at the same +time; but as fast as it is changed, it passes through the pyloric +orifice into the duodenum. + +_Observation._ The gastric juice has the property of coagulating +liquid albuminous matter when mixed with it. It is this property of +rennet, which is an infusion of the fourth stomach of the calf, by +which milk is coagulated, or formed into "curd." + +265. The CHYME is conveyed through the pyloric orifice of the stomach +into the duodenum. The chyme not only excites an action in the +duodenum, but also in the liver and pancreas. _Mucus_ is then secreted +by the duodenum, _bile_ by the liver, and _pancreatic fluid_ by the +pancreas. The bile and pancreatic fluid are conveyed into the +duodenum, and mixed with the chyme. By the action of these different +fluids, the chyme is converted into a fluid of a whitish color, called +_Chyle_, and into residuum. + +_Observation._ The bile has no agency in the change through which +the food passes in the stomach. In a healthy condition of this +organ, no bile is found in it. The common belief, that the stomach +has a redundancy of this secretion, is erroneous. If bile is ejected +in vomiting, it merely shows, not only that the action of the +stomach is inverted, but also that of the duodenum. A powerful +emetic will, in this way, generally bring this fluid from the most +healthy stomach. A knowledge of this fact might save many a stomach +from the evils of emetics, administered on false impressions of +their necessity, and continued from the corroboration of these by +the appearance of bile, till derangement, and perhaps permanent +disease, are the consequences. + +266. The CHYLE and residual matter are moved over the mucous surface +of the small intestine, by the action of its muscular coat. As the +chyle is carried along the tract of the intestine, it comes in contact +with the villi, where the lacteal vessels commence. These imbibe, or +take up, the chyle, and transfer it through the mesenteric glands into +the thoracic duct, through which it is conveyed into a large vein at +the lower part of the neck. In this vein the chyle is mixed with the +venous fluid. The residual matter is conveyed into the large +intestine, through which it is carried and excreted from the system. +(Appendix E.) + + -=-=-=-=-=-=-=-=-=-=-=-= + +What peculiar property has gastric juice? 265. Where and how is chyme +converted into chyle? What is said in regard to the bile? 266. What +becomes of the chyle? Of the residuum? + + -=-=-=-=-=-=-=-=-=-=-=-= + +267. In the process of digestion, the food is subjected to five +different changes. 1st. The chewing and admixture of the saliva with +the food; this process is called _mastication_. + +268. 2d. The change through which the food passes in the stomach by +its muscular contraction, and the secretion from the gastric glands; +this is called _chymification_. + +269. 3d. The conversion of the homogeneous chyme, by the agency of the +bile and pancreatic secretions, into a fluid of milk-like appearance; +this is _chylification_. + +270. 4th. The absorption of the chyle by the lacteals, and its +transfer through them and the thoracic duct, into the subclavian vein +at the lower part of the neck.[9] + + [9] The chyle is changed by the lacteals and mesenteric glands, but + the nature of this change is not, as yet, well defined or + understood. + +271. 5th. The separation and excretion of the residuum. + +272. Perfection of the second process of digestion requires thorough +and slow mastication. The formation of proper chyle demands +appropriate mastication and chymification; while a healthy action of +the lacteals requires that all the anterior stages of the digestive +process be as perfect as possible. (Appendix F.) + + -=-=-=-=-=-=-=-=-=-=-=-= + +267. Recapitulate the five changes in the digestive process. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Note._ Let the pupil review the anatomy and physiology of the +digestive organs from figs. 62 and 65, or from anatomical outline +plate No. 5. + +[Illustration: Fig. 65. An ideal view of the organs of digestion, opened +nearly the whole length. 1, The upper jaw. 2, The lower jaw. 3, The +tongue. 4, The roof of the mouth. 5, The oesophagus. 6, The trachea. 7, +The parotid gland. 8, The sublingual gland. 9, The stomach. 10, 10, The +liver. 11, The gall-cyst. 12, The duct that conveys the bile to the +duodenum, (13, 13.) 14, The pancreas. 15, 15, 15, 15, The small +intestine. 16, The opening of the small intestine into the large +intestine. 17, 18, 19, 20, The large intestine. 21, The spleen. 22, The +upper part of the spinal column.] + + + + +CHAPTER XV. + +HYGIENE OF THE DIGESTIVE ORGANS. + + +273. It is a law of the system, that each organ is excited to healthy +and efficient action, when influenced by its appropriate stimulus. +Accordingly, nutrient food, that is adapted to the wants of the +system, imparts a healthy stimulation to the salivary glands during +the process of mastication. The food that is well masticated, and has +blended with it a proper amount of saliva, will induce a healthy +action in the stomach. Well-prepared chyme is the natural stimulus of +the duodenum, liver, and pancreas; pure chyle is the appropriate +excitant of the lacteal vessels. + +274. The perfection of the digestive process, as well as the health of +the general system, requires the observance of certain conditions. +These will be considered under four heads:--1st. The _Quantity_ of +food that should be taken. 2d. Its _Quality_. 3d. The _Manner_ in +which it should be taken. 4th. The _Condition_ of the system when food +is taken. + +275. The QUANTITY of food necessary for the system varies. Age, +occupation, temperament, temperature, habits, amount of clothing, +health and disease are among the circumstances which produce the +variation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +273-330. _Give the hygiene of the digestive organs._ 273. Give a law +of the system. What is the appropriate stimulus of the salivary glands +during mastication? Of the stomach? Of the duodenum? Of the lacteal +vessels? 274. What does the perfection of the digestive organs +require? 275. What exert an influence on the quantity of food +necessary for the system? + + -=-=-=-=-=-=-=-=-=-=-=-= + +276. _The child and youth require food to promote the growth of the +different parts of the body._ The more rapid the growth of the child, +the greater the demand for food. This accounts for the keen appetite +and vigorous digestion in childhood. When the youth has attained his +full growth, this necessity for nutriment ceases; after this period of +life, if the same amount of food is taken, and there is no increase of +labor or exertion, the digestive apparatus will become diseased, and +the vigor of the whole system diminished. + +_Observation._ When the body has become emaciated from want of +nutriment, either from famine or disease, there is an increased demand +for food. This may be gratified with impunity until the individual has +regained the usual size, but repletion should be avoided. + +277. _Food is required to repair the waste, or loss of substance +that attends action._ In every department of nature, waste, or loss of +substance, attends and follows action. When an individual increases +his exercise,--changes from light to severe labor,--or the inactive +and sedentary undertake journeys for pleasure, the fluids of the +system circulate with increased energy. The old and exhausted +particles of matter are more rapidly removed through the action of +the vessels of the skin, lungs, kidneys, and other organs, and +their places are filled with new atoms, deposited by the small +blood-vessels. + +278. As the chyle supplies the blood with the newly vitalized +particles of matter, there is, consequently, an increased demand for +food. This want of the system induces, in general, a sensation of +hunger or appetite, which may be regarded as an indication of the +general state of the body. The sympathy that exists throughout the +system accords to the stomach the power of making known this state to +the nervous system, and, if the functions of this faithful monitor +have not been impaired by disease, abuse, or habit, the call is +imperious, and should be regarded. + + -=-=-=-=-=-=-=-=-=-=-=-= + +276. At what age is the appetite keen and the digestion vigorous? Why? +What is said in regard to the quantity of food when the youth has +attained his growth? What exception, as given in the observation? 277. +Give another demand for food. What effect has increased exercise upon +the system? 278. How are the new particles of matter supplied? What +does this induce? + + -=-=-=-=-=-=-=-=-=-=-=-= + +279. _When exercise or labor is lessened, the quantity of food should +be diminished._ When a person who has been accustomed to active +exercise, or even hard manual labor, suddenly changes to an employment +that demands less activity, the waste attendant on action will be +diminished in a corresponding degree; hence the quantity of food +should be lessened in nearly the same proportion as the amount of +exercise is diminished. If this principle be disregarded, the tone of +the digestive organs will be impaired, and the health of the system +enfeebled. + +280. This remark is applicable to those students who have left +laborious employments to attend school. Although the health is firm, +and the appetite keen from habit, yet every pupil should practise some +self-denial, and not eat as much as the appetite craves, the first +week of the session. After some days, the real wants of the system +will generally be manifested by a corresponding sensation of hunger. + +_Observation._ It is a common observation that in academies and +colleges, the older students from the country, who have been +accustomed to hard manual labor, suffer more frequently from defective +digestion and impaired health than the younger and feebler students +from the larger towns and cities. + +281. _Food is essential in maintaining a proper temperature of the +system._ The heat of the system, at least in part, is produced in the +minute vessels of the several organs, by the union of oxygen with +carbon and hydrogen, which the food and drink contain. The amount of +heat generated, is greatest when it is most rapidly removed from the +system, which occurs in cold weather. This is the cause of the system +requiring more food in winter than summer. + + -=-=-=-=-=-=-=-=-=-=-=-= + +279. Why should the quantity of food be diminished when the exercise +is lessened? What effect if this principle be disregarded? 280. To +what class is this remark applicable? What is often observed among +students in academies and colleges? 281. State another demand for +food. What is one source of heat in the body? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Persons that do not have food sufficient for the +natural wants of the system, require more clothing than those who are +well fed. + +282. The last-mentioned principle plainly indicates the propriety and +necessity of lessening the quantity of food as the warm season +approaches. Were this practised, the tone of the stomach and the vigor +of the system would continue unimpaired, the "season complaints" would +be avoided, and the "strengthening bitters" would not be sought to +create an appetite. + +_Observation._ Stable-keepers and herdsmen are aware of the fact, that +as the warm season commences, then animals require less food. Instinct +teaches these animals more truly, in this particular, than man allows +reason to guide him. + +283. _The quantity of food should have reference to the present +condition of the digestive organs._ If they are weakened or diseased, +so that but a small quantity of food can be properly digested or +changed, that amount only should be taken. Food does not invigorate +the system, except it is changed, as has been described in previous +paragraphs. + +_Observation._ When taking care of a sick child, the anxiety of the +mother and the sufferings of the child may induce her to give food +when it would be highly injurious. The attending physician is the only +proper person to direct what quantity should be given. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Why do we eat more in the winter than in the summer? What practical +observation is given? 282. Why should the quantity of food be lessened +as warm weather commences? What would be avoided if this principle +were obeyed? 283. Why should the present condition of the digestive +organs be regarded in reference to the quantity of food? Mention an +instance in which it would be injudicious to give food. + + -=-=-=-=-=-=-=-=-=-=-=-= + +284. _The quantity of food is modified, in some degree, by habit._ A +healthy person, whose exercise is in pure air, may be accustomed to +take more food than is necessary. The useless excess is removed from +the system by the waste outlets, as the skin, lungs, liver, kidneys, +&c. In such cases, if food is not taken in the usual quantity, there +will be a feeling of emptiness, if not of hunger, from the want of the +usual distention of the stomach. This condition of the digestive +organs may be the result of disease, but it is more frequently +produced by inordinate daily indulgence in eating, amounting almost to +gluttony. + +285. _Large quantities of food oppress the stomach, and cause general +languor of the whole body._ This is produced by the extra demands made +on the system for an increased supply of blood and nervous fluid to +enable the stomach to free itself of its burden. Thus, when we intend +to make any extraordinary effort, mental or physical, at least for one +meal, we should eat less food than usual, rather than a greater +quantity. + +286. _No more food should be eaten than is barely sufficient to +satisfy the appetite._ Nor should appetite be confounded with taste. +The one is a natural desire for food to supply the wants of the +system; the other is an artificial desire merely to gratify the +palate. + +287. Although many things may aid us in determining the quantity of +food proper for an individual, yet there is no certain guide in all +cases. It is maintained by some, that the sensation of hunger or +appetite is always an indication of the want of food, while the +absence of this peculiar sensation is regarded as conclusive evidence +that aliment is not demanded. This assertion is not correct, as an +appetite may be created for food by condiments and gormandizing, which +is as artificial and as morbid as that which craves tobacco or ardent +spirits. On the other hand, a structural or functional disease of the +brain may prevent that organ from taking cognizance of the sensations +of the stomach, when the system actually requires nourishment. +Observation shows, that disease, habit, the state of the mind, and +other circumstances, exert an influence on the appetite. + + -=-=-=-=-=-=-=-=-=-=-=-= + +284. Show the effect of habit upon the quantity of food that is eaten. +What is said in regard to inordinate eating? 285. What is the effect +of eating large quantities of food? What suggestion when an +extraordinary effort, either mental or physical, is to be made? 286. +How much food should generally be eaten? 287. What is the assertion of +some persons relative to the quantity of food necessary for the +system? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Dr. Beaumont noticed, in the experiments upon Alexis +St. Martin, that after a certain amount of food was converted into +chyme, the gastric juice ceased to ooze from the coats of the stomach. +Consequently, it has been inferred by some writers on physiology, that +the glands which supply the gastric fluid, by a species of instinctive +intelligence, would only secrete enough fluid to convert into chyme +the aliment needed to supply the real wants of the system. What are +the reasons for this inference? There is no evidence that the gastric +glands possess instinctive intelligence, and can there be a reason +adduced, why they may not be stimulated to extra functional action as +well as other organs, and why they may not also be influenced by +habit? + +288. While all agree that the remote or predisposing cause of hunger +is, usually, a demand of the system for nutrient material, the +proximate or immediate cause of the sensation of hunger is not clearly +understood. Some physiologists suppose that it is produced by an +engorged condition of the glands of the stomach which supply the +gastric juice; while others maintain that it depends on a peculiar +condition of the nervous system. + +289. The QUALITY of the food best adapted to the wants of the system +is modified by many circumstances. There are many varieties of food, +and these are much modified by the different methods of preparation. +The same kind of food is not equally well adapted to different +individuals, or to the same individual in all conditions; as vocation, +health, exposure, habits of life, season, climate, &c., influence the +condition of the system. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does observation show? 288. What is said of the causes of +hunger? 289. Why is not the same kind of food adapted to different +individuals? + + -=-=-=-=-=-=-=-=-=-=-=-= + +290. All articles of food may be considered in two relations: 1st, As +nutritive. 2d, As digestible. Substances are nutritious in proportion +to their capacity to yield the elements of chyle, of which carbon, +oxygen, hydrogen, and nitrogen are the most essential; they are +digestible in proportion to the facility with which they are acted +upon by the gastric juice. These properties should not be confounded +in the various articles used for food. + +291. As a "living body has no power of forming elements, or of +converting one elementary substance into another, it therefore follows +that the elements of which the body of an animal is composed must be +in the food." (Chap. III.) Of the essential constituents of the human +body, carbon, hydrogen, oxygen, and nitrogen are the most important, +because they compose the principal part of the animal body; while the +other elements are found in very small proportions, and many of them +only in a few organs of the system. (Appendix G.) + +_Observation._ Nitrogen renders food more stimulating, particularly if +combined with a large quantity of carbon, as beef. Those articles that +contain the greatest amount of the constituent elements of the system +are most nutritious. As milk and eggs contain all the essential +elements of the human system, so they are adapted to almost universal +use, and are highly nutritious. + + -=-=-=-=-=-=-=-=-=-=-=-= + +290. In what proportion are substances nutritious? Digestible? Why +does beef stimulate the system? What is said of milk and eggs? + + -=-=-=-=-=-=-=-=-=-=-=-= + +292. The following table, by Pereira, in his treatise on Food and +Diet may aid the student in approximating to correct conclusions of +the quantity of nutriment in different kinds of food, and its +adaptation to the wants of the system. + +TABLE, + +SHOWING THE AVERAGE QUANTITY OF DRY, OR SOLID MATTER, CARBON, +NITROGEN, AND MOISTURE, IN DIFFERENT ARTICLES OF DIET. + + -------------------+---------+---------+-----------+------------ + One hundred Parts. | Dry | Carbon. | Nitrogen. | Water + | Matter. | | | + -------------------+---------+---------+-----------+------------ + Arrowroot, | 81.8 | 36.4 | | 18.2 + Beans, | 85.89 | 38.24 | | 14.11 + Beef, fresh, | 25 | 12.957 | 3.752 | 75 + Bread, rye, | 67.79 | 30.674 | | 32.21 + Butter, | 100 | 65.6 | | + Cabbage, | 7.7 | | 0.28 | 92.3 + Carrot, | 12.4 | | 0.30 | 87.6 + Cherries, | 25.15 | | | 74.85 + Chickens, | 22.7 | | | 77.3 + Codfish, | 20 | | | 80 + Cucumbers, | 2.86 | | | 97.14 + Eggs, whites, | 20 | | | 80 + ----, yolk, | 46.23 | | | 53.77 + Lard, hog's, | 100 | 79.098 | | + Milk, cow's, | 12.98 | | | 87.02 + Oats, | 79.2 | 40.154 | 1.742 | 20.8 + Oatmeal, | 93.4 | | | 6.6 + Olive-oil, | 100 | 77.50 | | + Oysters, | 12.6 | | | 87.4 + Peaches, | 19.76 | | | 80.24 + Pears, | 16.12 | | | 83.88 + Peas, | 84 | 35.743 | | 16 + Plums, greengage, | 28.90 | | | 71.10 + Potatoes, | 24.1 | 10.604 | 0.3615 | 75.9 + Rye, | 83.4 | 38.530 | 1.417 | 16.6 + Suet, mutton, | 100 | 78.996 | | + Starch, potato, | 82 | 36.44 | | 18 + ----, wheat, | 85.2 | 37.5 | | 14.8 + Sugar, maple, | | 42.1 | | + ----, refined, | | 42.5 | | + ----, brown, | | 40.88 | | + Turnips, | 7.5 | 3.2175 | 0.1275 | 92.5 + Veal, roasted, | | 52.52 | 14.70 | + Wheat, | 85.5 | 39.415 | 1.966 | 14.5 + -------------------+---------+---------+-----------+------------ + +_Note._ Let the pupil mention those articles of food that are +most nutritious, from a review of this table, and the last four +paragraphs. + +293. Those articles that do not contain the essential elements of the +system should not be used as exclusive articles of diet. This +principle has been, and may be illustrated by experiment. Feed a dog +with pure sugar, or olive-oil, (articles that contain no nitrogen,) +for several weeks, and the evil effects of non-nitrogenous nutriment +will be manifested. At first, the dog will take his food with avidity, +and seem to thrive upon it; soon this desire for food will diminish, +his body emaciate, his eye become ulcerated, and in a few weeks he +will die; but mix bran or sawdust with the sugar or oil, and the +health and vigor of the animal will be maintained for months. A +similar phenomenon will be manifested, if grain only be given to a +horse, without hay, straw, or material of like character. (Appendix +H.) + +294. Some articles of food contain the elements of chyle in great +abundance, yet afford but little nutriment, because they are difficult +of digestion; while other articles contain but a small quantity of +these elements, and afford more nourishment, because they are more +easily affected by the digestive process. + + -=-=-=-=-=-=-=-=-=-=-=-= + +293. How has the effect of non-nitrogenous nutriment been illustrated? +294. Why do some articles of food that contain the elements of chyle +afford but little nutriment? Why do articles that contain a small +quantity of these elements afford more nourishment? 295. How was the +time required for digesting different articles of food ascertained? + + -=-=-=-=-=-=-=-=-=-=-=-= + +295. The following table exhibits the general results of experiments +made on Alexis St. Martin, by Dr. Beaumont, when he endeavored to +ascertain the time required for the digestion of different articles of +food.[10] The stomach of St. Martin was ruptured by the bursting of a +gun. When he recovered from the effects of the accident under the +surgical care of Dr. Beaumont, the stomach became adherent to the +side, with an external aperture. Nature had formed a kind of valve, +which closed the aperture from the interior, and thus prevented the +contents of the stomach from escaping; but on pushing it aside, the +process of digestion could be seen. Through this opening, the +appearance of the coats of the stomach and food, at different stages +of digestion, were examined. + + [10] The time required for the digestion of the different articles of + food might vary in other persons; and would probably vary in + the same individual at different periods, as the employment, + health, season, &c., exert a modifying influence. + +TABLE, + +SHOWING THE MEAN TIME OF DIGESTION OF THE DIFFERENT +ARTICLES OF DIET. + + -----------------------------+--------------+-------- + Articles. | Preparation. | Time + | | h. m. + -----------------------------+--------------+-------- + Apples, sour, hard, | Raw, | 2 50 + Apples, sour, mellow, | Raw, | 2 + Apples, sweet, do., | Raw, | 1 30 + Bass, striped, fresh, | Broiled, | 3 + Beans, pod, | Boiled, | 2 30 + Beef, fresh, lean, rare, | Roasted, | 3 + Beef, fresh, lean, dry, | Roasted, | 3 30 + Beef steak, | Broiled, | 3 + Beef, with salt only, | Boiled, | 3 36 + Beef, with mustard, | Boiled, | 3 10 + Beef, fresh, lean, | Fried, | 4 + Beef, old, hard, salted, | Boiled, | 4 15 + Beets, | Boiled, | 3 45 + Bread, wheat, fresh, | Baked, | 3 30 + Bread, corn, | Baked, | 3 15 + Butter, | Melted, | 3 30 + Cabbage head, | Raw, | 2 30 + Cabbage, with vinegar, | Raw, | 2 + Cabbage, | Boiled, | 4 30 + Cake, sponge, | Baked, | 2 30 + Carrot, orange, | Boiled, | 3 15 + Catfish, | Fried, | 3 30 + Cheese, old, strong, | Raw, | 3 30 + Chicken, full-grown, | Fricas'd, | 2 45 + Codfish, cured, dry, | Boiled, | 2 + Corn, green, & beans, | Boiled, | 3 45 + Corn bread, | Baked, | 3 15 + Corn cake, | Baked, | 3 + Custard, | Baked, | 2 45 + Dumpling, apple, | Boiled, | 3 + Ducks, domesticated, | Roasted, | 4 + Ducks, wild, | Roasted, | 4 30 + Eggs, fresh, | Boiled hard, | 3 30 + Eggs, fresh, | Boiled soft, | 3 + Eggs, fresh, | Fried, | 3 30 + Eggs, fresh, | Raw, | 2 + Flounder, fresh, | Fried, | 3 30 + Fowl, domestic, | Boiled, | 4 + Fowl, domestic, | Roasted, | 4 + Goose, | Roasted, | 2 30 + Lamb, fresh, | Broiled, | 2 30 + Liver, beef's, fresh, | Broiled, | 2 + Meat hashed with vegetables, | Warm'd, | 2 30 + Milk, | Boiled, | 2 + Milk, | Raw, | 2 15 + Mutton, fresh, | Roasted, | 3 15 + Mutton, fresh, | Broiled, | 3 + Mutton, fresh, | Boiled, | 3 + Oysters, fresh, | Raw, | 2 55 + Oysters, fresh, | Roasted, | 3 15 + Oysters, fresh, | Stewed, | 3 30 + Parsnips, | Boiled, | 2 30 + Pig, sucking, | Roasted, | 2 30 + Pigs' feet, soused, | Boiled, | 1 + Pork, fat and lean, | Roasted, | 5 15 + Pork, recently salted, | Boiled, | 4 30 + Pork, recently salted, | Fried, | 4 15 + Pork, recently salted, | Broiled, | 3 15 + Pork, recently salted, | Raw, | 3 + Pork, steak, | Broiled, | 3 15 + Potatoes, Irish, | Boiled, | 3 30 + Potatoes, Irish, | Baked, | 2 30 + Rice, | Boiled, | 1 + Sago, | Boiled, | 1 45 + Salmon, salted, | Boiled, | 4 + Sausage, fresh, | Broiled, | 3 20 + Soup, beef, vegetables, and | Boiled, | 4 + bread, | | + Soup, chicken, | Boiled, | 3 + Soup, mutton, | Boiled, | 3 30 + Soup, oyster, | Boiled, | 3 30 + Suet, beef, fresh, | Boiled, | 5 30 + Suet, mutton, | Boiled, | 4 30 + Tapioca, | Boiled, | 2 + Tripe, soused, | Boiled, | 1 + Trout, salmon, fresh, | Boiled, | 1 30 + Trout, salmon, fresh, | Fried, | 1 30 + Turkey, domesticated, | Roasted, | 2 30 + Turkey, | Boiled, | 2 25 + Turkey, wild, | Roasted, | 2 18 + Turnips, flat, | Boiled, | 3 30 + Veal, fresh, | Broiled, | 4 + Veal, fresh, | Fried, | 4 30 + Venison steak, | Broiled, | 1 35 + -----------------------------+--------------+-------- + +296. In view of this table, the question may be suggested, Is that +article of food most appropriate to the system which is most easily +and speedily digested? To this it may be replied, that the stomach is +subject to the same law as the muscles and other organs; exercise, +within certain limits, strengthens it. If, therefore, we always eat +those articles most easily digested, the digestive powers will be +weakened; if over-worked, they will be exhausted. Hence the kind and +amount of food should be adapted to the maintenance of the digestive +powers, and to their gradual invigoration when debilitated. + +_Observation._ Food that is most easily digested is not always most +appropriate to a person convalescing from disease. If the substance +passes rapidly through the digestive process, it may induce a +recurrence of the disease. Thus the simple preparations which are not +stimulating, as water-gruel, are better for a sick person than the +more digestible beef and fish. + +297. The question is not well settled, whether animal or vegetable +food is best adapted to nourish man. There are nations, particularly +in the torrid zone, that subsist, exclusively, on vegetables; while +those of the frigid zone feed on fish or animal food. In the temperate +zone, among civilized nations, a mixed diet is almost universal. When +we consider the organization of the human system, the form and +arrangement of the teeth, the structure of the stomach and intestines, +we are led to conclude, that both animal and vegetable food is +requisite, and that a mixed diet is most conducive to strength, +health, and long life. + + -=-=-=-=-=-=-=-=-=-=-=-= + +296. How is the question answered, whether that article is most +appropriate to the system which is most easily digested? Give +observation. 297. What is said of the adaptation of animal and +vegetable food to man? + + -=-=-=-=-=-=-=-=-=-=-=-= + +298. _The food should be adapted to the distensible character of the +stomach and alimentary canal._ The former will be full, if it contain +only a gill; it may be so distended as to contain a quart. The same is +true of the intestines. If the food is concentrated, or contains the +quantity of nutriment which the system requires, in small bulk, the +stomach and intestines will need the stimulation of distention and +friction, which is consequent upon the introduction and transit of the +innutritious material into and through the alimentary canal. If the +food is deficient in innutritious matter, the tendency is, to produce +an inactive and diseased condition of the digestive organs. For this +reason, nutrient food should have blended with it innutritious +material. Unbolted wheat bread is more healthy than hot flour cakes; +ripe fruits and vegetables than rich pies, or jellies. + +_Observation._ 1st. The observance of this rule is of more importance +to students, sedentary mechanics, and those individuals whose +digestive apparatus has been enfeebled, than to those of active habits +and firm health. + +2d. The circumstance that different articles of food contain different +proportions of waste, or innutritious matter, may be made practically +subservient in the following way: If, at any particular season of the +year, there is a tendency to a diarrhoea, an article that contains a +small proportion of waste should be selected for food; but, if there +is a tendency to an inactive or costive condition of the intestinal +canal, such kinds of food should be used as contain the greatest +proportion of waste, as such articles are most stimulating to the +digestive organs, and, consequently, most laxative. + +299. _In the selection of food, the influence of season and climate +should be considered._ Food of a highly stimulating character may be +used almost with impunity during the cold weather of a cold climate; +but in the warm season, and in a warm climate, it would be very +deleterious. Animal food, being more stimulating than vegetable, can +be eaten in the winter but vegetable food should be used more freely +in the spring and summer. + + -=-=-=-=-=-=-=-=-=-=-=-= + +298. What is said of the distensible character of the stomach and +alimentary canal? What is the effect of eating highly concentrated +food? Why is the unbolted wheat bread more healthy than flour cakes? +Give observation 1st. Observation 2d. 299. What kind of food is +adapted to cold weather? To warm weather? + + -=-=-=-=-=-=-=-=-=-=-=-= + +300. _The influence of food on the system is modified by the age of +the individual._ The organs of a child are more sensitive and +excitable than those of a person advanced in years. Therefore a +vegetable diet would be most appropriate for a child, while +stimulating animal food might be conducive to the health of a person +advanced in life. + +_Observation._ When the digestive organs are highly impressible or +diseased, it is very important to adopt a nutritious, unstimulating, +vegetable diet, as soon as the warm season commences. + +301. _Habit is another strong modifying influence._ If a person has +been accustomed to an animal or vegetable diet, and there is a sudden +change from one to the other, a diseased condition of the system, +particularly of the digestive apparatus, usually follows. When it is +necessary to change our manner of living, it should be done +gradually.[11] + + [11] The system is gradually developed, and all changes of food, + apparel, labor, exercise, or position, should be gradual. Even + a change from a bad to a good habit, on this principle, should + be gradual. + +302. _Some temperaments require more stimulating food than others._ As +a general rule, those persons whose sensations are comparatively +obtuse, and movements slow, will be benefited by animal food; while +those individuals whose constitutions are highly impressible, and +whose movements are quick and hurried, require a nutritious and +unstimulating vegetable diet. + + -=-=-=-=-=-=-=-=-=-=-=-= + +300. What kinds of food are appropriate to old age? Why? What kinds to +childhood? Why? 301. What is the effect when there is a sudden change +from a vegetable to an animal diet? How should all changes of the +system be made? 302. Do different temperaments require different kinds +of food? What general rule is given? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XVI. + +HYGIENE OF THE DIGESTIVE ORGANS, CONTINUED. + + +303. The MANNER in which food should be taken is of much practical +importance; upon it the health of the digestive organs measurably +depends. But few circumstances modify the proper manner of taking +food, or should exercise any controlling influence. + +304. _Food should be taken at regular periods._ The interval between +meals should be regulated by the character of the food, the age, +health, exercise, and habits of the individual. The digestive process +is more energetic and rapid in the young, active, and vigorous, than +in the aged, indolent, and feeble; consequently, food should be taken +more frequently by the former than by the latter class. + +305. In some young and vigorous persons, food may be digested in one +hour; in other persons, it may require four hours or more. The average +time, however, to digest an ordinary meal, will be from two to four +hours. In all instances, the stomach will require from one to three +hours to recruit its exhausted powers after the labor of digesting a +meal before it will again enter upon the vigorous performance of its +duties. + +306. _Food should not be taken too frequently._ If food is taken +before the stomach has regained its tone and energy by repose, the +secretion of the gastric juice, and the contraction of the muscular +fibres, will be imperfect. Again, if food is taken before the +digestion of the preceding meal has been completed, the effects will +be still worse, because the food partially digested becomes mixed with +that last taken. Therefore the interval between each meal should be +long enough for the whole quantity to be digested, and the time of +repose should be sufficient to recruit the exhausted organs. The +feebler the person and the more debilitated the stomach, the more +important to observe the above directions. + + -=-=-=-=-=-=-=-=-=-=-=-= + +303. Why is it important that we regard the manner of taking our food? +304. How should the intervals between meals be regulated? 305. What is +the average time required to digest an ordinary meal? 306. Why should +not food be taken too frequently? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ In the feeding of infants, as well as in supplying food +to older children, the preceding suggestions should always be +regarded. The person who has been confined by an exhausting sickness, +should most scrupulously regard this rule, if he wishes to regain his +strength and flesh with rapidity. As the rapidity of the digestive +process is less in students and individuals who are engaged in +sedentary employments, than in stirring agriculturists, the former +class are more liable to take food too frequently than the latter, +while its observance is of greater importance to the sedentary artisan +than to the lively lad and active farmer. + +307. _Food should be well masticated._ All solid aliments should be +reduced to a state of comparative fineness, by the teeth, before it is +swallowed; the gastric fluid of the stomach will then blend with it +more readily, and act more vigorously in reducing it to chyme. The +practice of swallowing solid food, slightly masticated, or "bolting" +it down, tends to derange the digestive process and impair the +nutrition of the system. + +308. _Mastication should be moderate, not rapid._ In masticating food, +the salivary glands are excited to action, and some time must elapse +before they can, secrete saliva in sufficient quantities to moisten +it. If the aliment is not supplied with saliva, digestion is retarded; +besides, in rapid eating, more food is generally consumed than the +system demands, or can be easily digested. Laborers, as well as men of +leisure, should have ample time for taking their meals. Imperfect +mastication is a prevailing cause of indigestion. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What persons would be benefited by observing the preceding remarks? +307. Why should food be well masticated? What is the effect of +"bolting down" food? 308. How should mastication be performed? Why? + + -=-=-=-=-=-=-=-=-=-=-=-= + +309. _Food should be masticated and swallowed without drink._ As the +salivary glands supply fluid to moisten the dry food, the use of tea, +coffee, water, or any other fluid, is not demanded by nature's laws +while taking a meal. One objection to "washing down" the food with +drink is, the aliment is moistened, not with the saliva, but with the +drink. This tends to induce disease, not only in the salivary organs, +by leaving them in a state of comparative inactivity, but in the +stomach, by the deficiency of the salivary stimulus. Another is, large +quantities of fluids, used as drinks, give undue distention to the +stomach, and lessen the energy of the gastric juice by its dilution, +thus retarding digestion. Again, drinks taken into the stomach must be +removed by absorption before the digestion of other articles is +commenced. + +_Observation._ Were it customary not to place drinks on the table +until the solid food is eaten, the evil arising from drinking too much +at meals would be obviated. The horse is never known to leave his +provender, nor the ox his blade of grass, to wash it down; but many +persons, from habit rather than thirst, drink largely during meals. + +310. The peculiar sensation in the mouth and fauces, called thirst, +may not always arise from the demand for fluids to increase the +_serum_ (water) of the blood, as in the desire for drink attendant on +free perspiration, for then, pure water or some diluent drink is +absolutely necessary; but it may be the result of fever, or local +disease of the parts connected with the throat. In many instances, +thirst may be allayed by chewing some hard substance, as a dry +cracker. This excites a secretion from the salivary glands, which +removes the disagreeable sensation. In thirst, attendant on a heated +condition of the system, this practice affords relief, and is safe; +while the practice of drinking large quantities of cold fluids, is +unsafe, and should never be indulged. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Why should all persons have ample time for eating? 309. Why are drinks +not necessary while masticating food? Give the objections to "washing +down" food. What observation relative to drink? 310. Does the +sensation of thirst always arise from a real want of the system? + + -=-=-=-=-=-=-=-=-=-=-=-= + +311. _Food or drink should not be taken when very hot._ When food or +drink is taken hot, the vessels of the mucous membrane of the gums, +mouth, and stomach are unduly stimulated for a short time; and this is +followed by reaction, attended by a loss of tone, and debility of +these parts. This practice is a fruitful cause of spongy gums, decayed +teeth, sore mouth, and indigestion. + +312. _Food or drink should not be taken very cold._ If a considerable +quantity of very cold food or liquid be taken immediately into the +stomach, the health will be endangered, and the tone of the system +will be impaired, from the sudden abstraction of heat from the coats +of the stomach, and from surrounding organs, to impart warmth to the +cold food or drink. This arrests the digestive process, and the food +is retained in the stomach too long, and causes oppression and +irritation. Consequently, food and drink that are moderately heated +are best adapted to the natural condition of the digestive apparatus. + +_Observation._ Food of an injurious quality, or taken in an improper +manner, affects the inferior animals as well as man. The teeth of cows +that are closely penned in cities, and are fed on distillery slops, or +the unhealthy slops and remnants of kitchens, decay and fall out in +about two years. Can the milk of such diseased animals be healthy--the +proper nourishment for children? + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give instances when it does and when it does not. 311. Why should not +food or drink be taken hot? 312. Why should they not be taken cold? +Show some of the effects of improper food upon the inferior animals. + + -=-=-=-=-=-=-=-=-=-=-=-= + +313. The CONDITION of the system should be regarded when food is +taken. This is necessary, as the present and ulterior condition of the +digestive apparatus is strongly influenced by the state of the other +organs of the system. + +314. _Food should not be taken immediately after severe exertion, +either of the body or mind._ For all organs in action require and +receive more blood and nervous fluid, than when at rest. This is true +of the brain, muscles, and vocal organs, when they have been actively +exercised. The increased amount of fluid, both sanguineous and +nervous, supplied to any organ during extra functional action, is +abstracted from other parts of the system. This enfeebles and +prostrates the parts that supply the blood and nervous fluid to the +active organ. Again, when any organ has been in vigorous action for a +few hours, some time will elapse before the increased action of the +arteries and nerves abates, and a due supply of fluids is transmitted +to other organs, or an equilibrium of action in the system is +reestablished. + +315. Thus food should not be taken immediately after severe mental +labor, protracted speaking, continued singing, or laborious manual +toil; as the digestive organs will be in a state of comparative +debility, and consequently unfit to digest food. From thirty to sixty +minutes should elapse, after the cessation of severe employment, +before food is taken. This time may be spent in cheerful amusement or +social conversation. + +_Observation._ The practice of students and accountants going +immediately from severe mental labor to their meals, is a pernicious +one, and a fruitful cause of indigestion and mental debility. The +custom of farmers and mechanics hurrying from their toil to the +dinner-table, does much to cause dyspepsia and debility among these +classes in community. + + -=-=-=-=-=-=-=-=-=-=-=-= + +313. Should the condition of the system be regarded in taking food? +314. When should food not be taken? Why? What is the result when an +organ has been in vigorous action? 315. After the cessation of severe +toil, how much time should expire before eating? What is one cause of +indigestion among students and accountants? + + -=-=-=-=-=-=-=-=-=-=-=-= + +316. _Severe mental or manual toil should not be entered upon +immediately after eating._ As there is an increased amount of blood +and nervous fluid supplied to the stomach and alimentary canal during +the digestion of food, a deficiency exists in other organs. This is +evinced by a slight paleness of the skin, and a disinclination to +active thought and exercise. Under such circumstances, if either the +mind, vocal organs, or muscles are called into energetic action, there +will be an abstraction of the necessary amount of blood and nervous +fluid from the stomach, and the process of digestion will be arrested. +This will not only cause disease of the digestive organs, but chyle +will not be formed, to nourish the system. + +_Illustration._ An English gentleman fed two dogs upon similar +articles of food. He permitted one to remain quiet in a dark room; the +other he sent in pursuit of game. At the expiration of one hour, he +had both killed. The stomach of the dog that had remained quiet was +nearly empty. The food had been properly changed and carried forward +into the alimentary canal. In the stomach of the dog that had used his +muscles in chasing game, the aliment remained nearly unaltered. + +317. The same principle may be applied to the action of the organs of +man. If his mind or muscles act intensely soon after eating, the +stomach will not be sufficiently stimulated by blood and nervous fluid +to change the food in a suitable period. The Spanish practice of +having a "siesta," or sleep after dinner, is far better than the +custom of the Anglo-Saxon race, who hurry from their meals to the +field, shop, or study, in order to save time, which, in too many +instances, is lost by a sense of oppression and suffering which soon +follows. + + -=-=-=-=-=-=-=-=-=-=-=-= + +316. Why should not severe manual or mental exertion be made +immediately after eating? State the illustration. 317. May this +principle be applied to the action of the human stomach? What is said +of the Spanish custom of resting after dinner? + + -=-=-=-=-=-=-=-=-=-=-=-= + +318. In some instances of good health, the infringement of this +organic law may seem to pass with impunity, but Nature, though +lenient, sooner or later asserts her claims. The practice of the +Spaniard may be improved by indulging, for an hour before resuming +toil, in moderate exercise of the muscular system, conjoined with +agreeable conversation and a hearty laugh, as this facilitates +digestion, and tends to "shake the cobwebs from the brain." + +_Observation._ No judicious teamster drives his animals as soon as +they have swallowed their food, but gives them a period for repose, so +that their food may be digested, and their systems invigorated. In +this way, he secures the greatest amount of labor from his team. + +319. _The mind exerts an influence upon the digestive process._ This +is clearly exhibited, when an individual receives intelligence of the +loss of a friend or of property. He may at the time be sitting before +a plentiful board, with a keen appetite; but the unexpected news +destroys it, because the excited brain withholds its stimulus. This +shows the propriety of avoiding absorbing topics of thought at meals, +as labored discussions and matters of business; but substitute +cheerful and light conversation, enlivening wit, humor, the social +intercourse of family and friends; these keep the brain in action, but +not in toil. Under such circumstances, the blood and nervous fluid +flow freely, the work of digestion is readily commenced, and easily +carried on. + +320. _Indigestion arising from a prostration of the nervous system, +should be treated with great care._ The food should be simple, +nutritious, moderate in quantity, and taken at regular periods. Large +quantities of stimulating food, frequently taken, serve to increase +the nervous prostration. Those afflicted should exercise in the open +air, and engage in social conversation, that the brain may be excited +to a natural or healthy action, in order that it may impart to the +digestive organs the necessary stimulation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Of the Anglo-Saxon race? 318. How can the Spanish custom be improved? +319. How is the influence of the mind on the digestive process +exhibited? What does it show the necessity of avoiding? 320. How +should indigestion arising from nervous prostration be treated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +321. _Persons should abstain from eating, at least three hours before +retiring for sleep._ It is no unusual occurrence, for those persons +who have eaten heartily immediately before retiring to sleep, to have +unpleasant dreams, or to be aroused from their unquiet slumber by +colic pains. In such instances, the brain becomes partially dormant, +and does not impart to the digestive organs the requisite amount of +nervous influence. The nervous stimulus being deficient, the unchanged +food remains in the stomach, causing irritation of this organ. + +_Illustration._ A healthy farmer, who was in the habit of eating one +fourth of a mince pie immediately before going to bed, became annoyed +with unpleasant dreams, and, among the varied images of his fancy, he +saw that of his deceased father. Becoming alarmed, he consulted a +physician, who, after a patient hearing of the case, gravely advised +him to eat _half_ of a mince pie, assuring him that he would then see +his grandfather. + +322. _When the general system and digestive organs are enfeebled, +mild, unstimulating food, in small quantities, should be given._ In +the instance of a shipwrecked and famished mariner, or a patient +recovering from disease, but a small quantity of nourishment should be +given at a time. The reason for this, is, that when the stomach is +weakened from want of nourishment, it is as unfitted for a long period +of action in digesting food, as the muscles are, under like +circumstances, for walking. Consequently, knowledge and prudence +should direct the administration of food under these circumstances. +The popular adage, that "food never does harm when there is a desire +for it," is untrue, and, if practically adopted, may be injurious and +destructive to life. + + -=-=-=-=-=-=-=-=-=-=-=-= + +321. What is the effect of eating immediately before retiring for +sleep? How is this illustrated in the case of a healthy farmer? 322. +How should the food be given when both the digestive organs and +general system are debilitated? Give the reason. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Liquids are rapidly removed from the stomach by +absorption. Hence, in cases of great prostration, when it is desirable +to introduce nutriment into the system, without delay, the animal and +vegetable broths are a desirable and convenient form of supplying +aliment. + +323. _The condition of the skin exercises an important influence on +the digestive apparatus._ Let free perspiration be checked, either +from uncleanliness or from chills, and it will diminish the functional +action of the stomach and its associated organs. This is one of the +fruitful causes of the "liver and stomach complaints" among the +half-clothed and filthy population of the crowded cities and villages +of our country. Attention to clothing and bathing would likewise +prevent many of the diseases of the alimentary canal, called "season +complaints," particularly among children. + +324. _Restricting the movements of the ribs and diaphragm impairs +digestion._ At each full inspiration, the ribs are elevated, and the +central portion of the diaphragm is depressed, from one to two inches. +This depression is accompanied by a relaxation of the anterior +abdominal walls. At each act of expiration, the relaxed abdominal +muscles contract, the ribs are depressed, the diaphragm relaxes, and +its central parts ascend. These movements of the midriff cause the +elevation and depression of the stomach, liver, and other abdominal +organs, which is a natural stimulus of these parts. + + -=-=-=-=-=-=-=-=-=-=-=-= + +In cases of great prostration, what is recommended? 323. How is the +influence that the skin exercises on the digestive organs illustrated? +324. What effect on the digestive process has the restriction of the +ribs and diaphragm? + + -=-=-=-=-=-=-=-=-=-=-=-= + +325. It is noted of individuals who restrain the free movements of the +abdominal muscles by tight dresses, that the tone and vigor of the +digestive organs are diminished. The restricted waist will not admit +of a full and deep inspiration and so essential is this to health, +that abuse in this respect soon enfeebles and destroys the functions +of the system. + +326. _Pure air is necessary to give a keen appetite and vigorous +digestion._ The digestive organs not only need the stimulus of blood, +but they absolutely need the influence of pure blood, which cannot +exist in the system, except when we breathe a pure air. From this we +learn why those persons who sleep in small, ill ventilated rooms, have +little or no appetite in the morning, and why the mouth and throat are +so dry and disagreeable. The effect of impure blood, in diminishing +the desire for food, and enfeebling the digestive organs, is well +illustrated by the following incidents. + +_Illustrations._ 1st. Dr. Reid, in his work on "Ventilation of Rooms," +relates that an innkeeper in London, when he provided a public dinner, +always spread his tables in an under-ground room, with low walls, +where the air was confined and impure. He assigned as a reason for so +doing, that his guests consumed only one third as much food and wine, +as if the tables were laid in the open air. + +2d. A manufacturer stated before a committee of the British +Parliament, that he had removed an arrangement for ventilating his +mill, because he noticed that his men ate much more after his mill was +ventilated, than previous to admitting fresh air into the rooms, and +that he could not _afford_ to have them breathe pure air. + +_Observation._ Many of the cases of indigestion among clergymen, +seamstresses, school teachers, sedentary mechanics, and factory +operatives, are produced by breathing the impure air of the rooms they +occupy. These cases can be prevented, as well as cured, by proper +attention to ventilation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +325. What is observed of those individuals that restrict the movements +of the abdominal muscles? 326. Why is pure air necessary to vigorous +digestion? Give illustration 1st. Illustration 2d. What is one cause +of indigestion among the sedentary class in community? + + -=-=-=-=-=-=-=-=-=-=-=-= + +327. _The position of a person, in standing or sitting, exerts an +influence upon the digestive organs._ If a person lean, or stoop +forward, the distance between the pelvic bones and the diaphragm is +diminished. This prevents the depression of the diaphragm, while the +stomach, liver, pancreas, and other abdominal organs, suffer +compression, which induces many severe diseases of these organs. As +healthy and well-developed muscles keep the spinal column in an erect +position, which conduces to the health of the organs of digestion, the +child should be taught to avoid all positions _but the erect_, while +studying or walking. This position, combined with unrestricted waists, +will do much to remove the now prevalent disease, dyspepsia. + +328. _Whatever kind of aliment is taken, it is separated into +nutriment and residuum_; the former of which is conveyed, through the +medium of the circulation, to all organs of the system, and the +latter, if not expelled, accumulates, causing headache and dizziness, +with a general uneasiness; and, if allowed to continue, it lays the +foundation of a long period of suffering and disease. For the +preservation of health, it is necessary that there should be a daily +evacuation of the residual matter. + +_Observation._ In chronic diseases of the digestive organs, very +frequently, there is an inactive, or costive condition of the +alimentary canal. This may be removed in many cases, and relieved in +all instances, by friction over the abdominal organs, and by making an +effort at some stated period each day, (evening is best,) to evacuate +the residuum. In acute diseases, as fever, regard should be given to +regularity in relieving the intestines of residuum. Attention to this +suggestion will in many instances obviate the necessity of cathartic +medicine. + + -=-=-=-=-=-=-=-=-=-=-=-= + +327. Why does the position of a person affect digestion? 328. Into +what are different kinds of aliment separated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +329. We would add, for the benefit of those afflicted with hemorrhoids, +or piles, that the best time for evacuating the intestinal canal +would be immediately before retiring for the night. During the +night, while recumbent, the protruding parts return to their proper +place, and the surrounding organs acquire increased tone to retain them. +The same observance will do much to prevent such prostrating +diseases.[12] + + [12] The urinary organs, as well as the intestinal canal, should be + frequently and regularly evacuated. Some most distressing and + frequently incurable complaints are caused by false customs and + false delicacy in this particular. Teachers should be + particularly careful, and regard this suggestion in reference + to young pupils. + +330. To recapitulate: digestion is most perfect when the action of the +cutaneous vessels is energetic; the brain and vocal organs moderately +stimulated by animated conversation; the blood well purified; the +muscular system duly exercised; the food of an appropriate quality, +taken in proper quantities, at regular periods, and also properly +masticated. + + -=-=-=-=-=-=-=-=-=-=-=-= + +330. Give the summary when digestion is most perfect. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER VXII. + +THE CIRCULATORY ORGANS. + + +331. The ultimate object of the food and drink introduced into the +body, is to furnish material to promote the growth and repair the +waste of the organs of the system. The formation of chyle (the +nutrient portion of the food) has been traced through the digestive +process, and its transfer into the vein at the lower part of the neck, +from which it is conveyed to the heart; and, finally, in the lungs it +assimilates to the character of blood. + +332. The BLOOD, after standing a short time, when drawn from its +vessels, separates into _se'rum_, (a watery fluid,) and _co-ag'u-lum_, +(clot.) This fluid is distributed to every part of the system. There +is no part so minute that it does not receive blood. The organs by +which this distribution is effected are so connected that there is +properly neither beginning nor end; but as it respects their +functions, they are connected in a complete circle. From this +circumstance, they are called the _Circulatory Organs_. + + +ANATOMY OF THE CIRCULATORY ORGANS. + +333. The CIRCULATORY ORGANS are the _Heart_, _Ar'te-ries_, _Veins_, +and _Cap'il-la-ries_. + +334. The HEART is placed obliquely, in the left cavity of the chest, +between the right and left lung. Its general form is that of an +inverted cone, the base of which is directed upward and backward, +toward the right shoulder, while its apex points forward to the left +side, about three inches from the sternum to the space between the +fifth and sixth ribs. Its under side rests upon the tendinous portion +of the diaphragm. The heart is surrounded by a sac, called the +_per-i-car'di-um_, (heart-case.) The interior surface of this membrane +secretes a watery fluid, that lubricates the exterior of the heart, +and obviates friction between it and the pericardium. + + -=-=-=-=-=-=-=-=-=-=-=-= + +331. what is the ultimate object of the food? 332. Of what is the +blood composed? What is said of the distribution of the blood? 333. +Name the circulatory organs. 334-351. _Give the anatomy of the +circulatory organs._ 334. Describe the heart. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 66. A front view of the heart. 1, The right auricle +of the heart. 2, The left auricle. 3, The right ventricle. 4, The left +ventricle. 5, 6, 7, 8, 9, 10, The vessels[13] through which the blood +passes to and from the heart.] + +[Illustration: Fig. 67. A back view of the heart. 1, The right auricle. +2, The left auricle. 3, The right ventricle. 4, The left ventricle. 5, 6, +7, The vessels that carry the blood to and from the heart. 9, 10, 11, The +nutrient vessels of the heart.] + + [13] All vessels that carry blood to the heart, are called _veins_. + All vessels that carry blood _from_ the heart, are called + _arteries_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +With what is it surrounded? What is its use? How much fluid does this +membrane contain when healthy? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ In health, there is usually about a tea-spoonful of +fluid in the pericardium. When these parts are diseased, it may be +thrown out more abundantly, and sometimes amounts to several ounces, +producing a disease called dropsy of the heart. But all the unpleasant +sensations in the region of the heart are not caused by an increased +amount of fluid in the pericardium, as this disease is not of frequent +occurrence. + +335. The heart is composed of muscular fibres, that traverse it in +different directions, some longitudinally, but most of them in a +spiral direction. The human heart is a double organ, or it has two +sides, called the right and the left. The compartments of the two +sides are separated by a muscular _sep'tum_, or partition. Again, each +side of the heart is divided into two parts, called the _Au'ri-cle_ +(deaf ear) and the _Ven'tri-cle_. + +[Illustration: Fig. 68. A section of the heart, showing its cavities and +valves. 3, The right auricle. 4, The opening between the right auricle +and right ventricle. 5, The right ventricle. 6, The tricuspid valves. 7, +The pulmonary artery. 9, The semilunar valves of the pulmonary artery. +10, The septum between the right and left ventricle. 12, The left +auricle. 13, The opening between the left auricle and left ventricle. 14, +The left ventricle. 15, The mitral valves. 16, The aorta. 17, The +semilunar valves of the aorta.] + +336. The AURICLES differ in muscularity from the ventricles. Their +walls are thinner, and of a bluish color. These cavities are a kind of +reservoir, designed to contain the blood arriving by the veins. + +337. The VENTRICLES not only have their walls thicker than the +auricles, but they differ in their internal structure. From the +interior of these cavities arise fleshy columns, called _co-lum'nae +car'ne-ae_. The walls of the left ventricle are thicker and stronger +than those of the right. + + -=-=-=-=-=-=-=-=-=-=-=-= + +335. Of what is the heart composed? Give its divisions. 336. Describe +the auricles. 337. Describe the ventricles. + + -=-=-=-=-=-=-=-=-=-=-=-= + +338. The cavities in the right side of the heart are triangular in +shape; those of the left, oval. Each cavity will contain about two +ounces of blood. Between the auricle and ventricle in the right side +of the heart, there are three folds, or doublings, of thin, triangular +membrane, called the _tri-cus'pid_ valves. Between the auricle and +ventricle in the left side, there are two valves, called the +_mi'tral_. There are seen passing from the floating edge of these +valves to the columnae carneae, small white cords, called _chor'dae +ten'di-nae_, which prevent the floating edge of the valve from being +carried into the auricle. + +339. The right ventricle of the heart gives rise to the _Pul'mo-na-ry_ +artery; the left ventricle, to a large artery called the _A-ort'a_. At +the commencement of each of these arteries there are three folds of +membrane, and from their shape, they are called _sem-i-lu'nar_ +valves. + +340. The heart is supplied with arteries and veins, which ramify +between its muscular fibres, through which its _nutrient_ blood +passes. It has, likewise, a few lymphatics, and many small nervous +filaments from the sympathetic system of nerves. This organ, in its +natural state, exhibits but slight indications of sensibility, and +although nearly destitute of the sensation of touch, it is yet, +however, instantly affected by every painful bodily excitement, or +strong mental emotions. + +_Observation._ To obtain a clear idea of the heart and its valves, it +is recommended to examine this part of an ox or calf. In order that +each ventricle be opened without mutilating the fleshy columns, +tendinous cords, and valves, cut on each side of the septum parallel +to it. This may be easily found between the ventricles, as they differ +in thickness. + + -=-=-=-=-=-=-=-=-=-=-=-= + +338. How do the cavities in the heart differ? What is found between +the auricle and ventricle in the right side of the heart? How many +valves in the left side, and their names? Where are the tendinous +cords, and what is their use? 339. What vessels proceed from the +ventricles? What is said of their valves? 340. With what is the heart +supplied? What is said of its sensibility? How can an idea of the +structure of the heart be obtained? + + -=-=-=-=-=-=-=-=-=-=-=-= + +341. The ARTERIES are the cylindrical tubes that convey the blood from +the heart to every part of the system. They are dense in structure, +and preserve, for the most part, the cylindrical form, when emptied of +their blood, which is their condition after death. + +342. The arteries are composed of three coats. The external, or +cellular coat, is firm and strong; the middle, or fibrous coat, is +composed of yellowish fibres. This coat is elastic, fragile, and +thicker than the external coat. Its elasticity enables the vessel to +accommodate itself to the quantity of blood it may contain. The +internal coat is a thin, serous membrane, which lines the interior of +the artery, and gives it the smooth polish which that surface +presents. It is continuous with the lining membrane of the heart. + +343. Communications between arteries are free and numerous. They +increase in frequency with diminution in the size of the branches, so +that through the medium of the minute ramifications, the entire body +may be considered as one circle of inosculation. The arteries, in +their distribution through the body, are enclosed in a loose, cellular +investment, called a sheath, which separates them from the surrounding +tissues. + +344. The PULMONARY ARTERY commences in front of the origin of the +aorta. It ascends obliquely to the under surface of the arch of the +aorta, where it divides into two branches, one of which passes to the +right, the other to the left lung. These divide and subdivide in the +structure of the lungs, and terminate in the capillary vessels, which +form a net-work around the air-cells, and become continuous with the +minute branches of the pulmonary veins. This artery conveys the impure +blood to the lungs, and, with its corresponding veins, establishes the +_lesser_, or _pulmonic circulation_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +341. What are arteries? 342. Give their structure. 343. What is said +of the communications between the arteries? In their distribution, how +are they separated from the surrounding tissues? 344. Describe the +pulmonary artery. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: The divisions of this artery continue to divide and +subdivide, until they become no larger than hairs in size. These minute +vessels pass over the air-cells, represented by small dark points around +the margin of the lungs.] + +345. The AORTA proceeds from the left ventricle of the heart, and +contains the pure, or nutrient blood. This trunk gives off branches, +which divide and subdivide to their ultimate ramifications, +constituting the great arterial tree which pervades, by its minute +subdivisions, every part of the animal frame. This great artery and +its divisions, with their returning veins, constitute the _greater_, +or _systemic circulation_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does this artery and its corresponding veins establish? Explain +fig. 69. 345. Describe the aorta. What do this artery and its +corresponding veins constitute? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 70. The aorta and its branches. 1, The commencement +of the aorta. 2, The arch of the aorta. 3, The carotid artery. 4, The +temporal artery. 5, The subclavian artery. 6, The axillary artery. 7, The +brachial artery. 8, The radial artery. 9, The ulnar artery. 10, The iliac +artery. 11, The femoral artery. 12, The tibial artery, 13. The peroneal +artery.] + +346. The VEINS are the vessels which return the blood to the auricles +of the heart, after it has been circulated by the arteries through +the various tissues of the body. They are thinner and more delicate in +structure than the arteries, so that when emptied of their blood, they +become flattened and collapsed. The veins commence by minute radicles +in the capillaries, which are every where distributed through the +textures of the body, and coalesce to constitute larger and larger +branches, till they terminate in the large trunks which convey the +dark-colored blood directly to the heart. In diameter they are much +larger than the arteries, and, like those vessels, their combined area +would constitute an imaginary cone, the apex of which is placed at the +heart, and the base at the surface of the body. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does fig. 70 represent? 346. What are the veins? + + -=-=-=-=-=-=-=-=-=-=-=-= + +347. The communications between the veins are more frequent than +between the arteries, and take place between the larger as well as +among the smaller vessels. The office of these inosculations is very +apparent, as tending to obviate the obstructions to which the veins +are peculiarly liable, from the thinness of their coats, and from +inability to overcome great impediments by the force of their current. +These tubes, as well as the arteries, are supplied with nutrient +vessels, and it is to be presumed that nervous filaments from the +sympathetic nerves are distributed to their coats. + +348. The external, or cellular coat of the veins, is dense and firm, +resembling the cellular tunic of the arteries. The middle coat is +fibrous, like that of the arteries, but extremely thin. The internal +coat is serous, and also similar to that of the arteries. It is +continuous with the lining membrane of the heart at one extremity, and +with the lining membrane of the capillaries at the other. + +349. At certain intervals, the internal coat forms folds, or +duplicatures, which constitute valves. They are generally composed of +two semilunar folds, one on each side of the vessel. The free +extremity of the valvular folds is concave, and directed forward, so +that while the current of blood sets toward the heart, they present no +impediment to its free passage; but let the current become retrograde, +and it is impeded by their distention. The valves are most numerous in +the veins of the extremities, particularly the deeper veins situated +between the muscles; but in some of the larger trunks, and also in +some of the smaller veins, no valves exist. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Where do they commence? 347. What is said of their communications? +What is the apparent design of the inosculations of the veins? What +vessels are distributed to the coats of the veins? 348. Give the +structure of the coats of the veins. 349. How are the valves in the +veins formed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 71. A vein laid open to show the valves. 1, The trunk +of the vein. 2, 2, Its valves. 3, An opening of a branch into the main +trunk.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is their use? Where are they the most numerous? + + -=-=-=-=-=-=-=-=-=-=-=-= + +350. The CAPILLARIES constitute a microscopic net-work, and are so +distributed through every part of the body as to render it impossible +to introduce the smallest needle beneath the skin, without wounding +several of these fine vessels. They are remarkable for the uniformity +of diameter, and for the constant divisions and communications which +take place between them. + +351. The capillaries inosculate, on the one hand, with the terminal +extremity of the arteries, and on the other, with the commencement of +the veins. They establish the communication between the termination of +the arteries and the beginning of the veins. The important operations +of secretion and the conversion of the nutrient materials of the blood +into bone, muscle, &c., are performed in these vessels. + +[Illustration: Fig. 72. An ideal view of a portion of the pulmonic +circulation. 1, 1, A branch of the artery that carries the impure blood +to the lungs. 3, 3, Capillary vessels. 2, 2, A vein through which red +blood is returned to the left side of the heart.] + +[Illustration: Fig. 73. An ideal view of a portion of the systemic +circulation. 1, 1, A branch of the aorta. This terminates in the +capillaries, (3, 3.) 2, 2, A vein through which the impure blood is +carried to the right side of the heart.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +350. What do the capillaries constitute? For what are they remarkable? +351. What relation do they bear to the arteries and veins? What +important operations are performed in these vessels? What is +represented by fig. 72? By fig. 73? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XVIII. + +PHYSIOLOGY OF THE CIRCULATORY ORGANS. + + +352. The walls of all the cavities of the heart are composed of +muscular fibres, which are endowed with the property of contracting +and relaxing, like the muscles of the extremities. The contraction and +relaxation of the muscular tissue of the heart, produce a diminution +and enlargement of both auricular and ventricular cavities. The +auricles contract and dilate simultaneously, and so do the ventricles; +yet the contraction and dilatation of the auricles do not alternate +with the contraction and dilatation of the ventricles, as the +dilatation of the one is not completed before the contraction of the +other commences. The dilatation of the ventricles is termed the +_di-as'to-le_ of the heart; their contraction, its _sys'to-le_. + +353. The ventricles contract quicker and more forcibly than the +auricles, and they are three times longer in dilating than contracting. +The walls of the right ventricle, being thinner than the left, are more +distensible, and thus this cavity will contain a greater amount of +blood. This arrangement adapts it to the venous system, which is +more capacious than the arterial. The thicker and more powerful walls of +the left ventricle adapt it to expel the blood to a greater distance. + +354. The valves in the heart permit the blood to flow from the +auricles to the ventricles, but prevent its reflowing. The valves at +the commencement of the aorta and pulmonary artery, permit the blood +to flow from the ventricles into these vessels, but prevent its +returning. + + -=-=-=-=-=-=-=-=-=-=-=-= + +352-366. _Give the physiology of the circulatory organs._ 352. What do +the contraction and relaxation of the muscular walls of the heart +produce? How do the auricles and ventricles contract and dilate? 353. +What is said of the contraction and dilatation of the ventricles in +the heart? How is the right ventricle adapted to its function? How the +left? 354. What is the use of the valves in the heart? Those of the +aorta and pulmonary artery? + + -=-=-=-=-=-=-=-=-=-=-=-= + +355. The function of the different parts of the heart will be given, +by aid of fig. 74. The blood passes from the right auricle (3) into +the right ventricle, (5,) and the tricuspid valves (6) prevent its +reflux; from the right ventricle the blood is forced into the +pulmonary artery, (7,) through which it passes to the lungs. The +semilunar valves (9) prevent this circulating fluid returning to the +ventricle. The blood, while passing over the air-cells in the lungs, +in the minute divisions of the pulmonary artery, is changed from a +bluish color to a bright red. It is then returned to the left auricle +of the heart by the pulmonary veins, (11, 11.) + +[Illustration: Fig. 74. 1, The descending vena cava, (vein.) 2, The +ascending vena cava, (vein.) 3, The right auricle. 4, The opening between +the right auricle and the right ventricle. 5, The right ventricle. 6, The +tricuspid valves. 7, The pulmonary artery. 8, 8, The branches of the +pulmonary artery that pass to the right and left lung. 9, The semilunar +valves of the pulmonary artery. 10, The septum between the two ventricles +of the heart. 11, 11, The pulmonary veins. 12, The left auricle. 13, The +opening between the left auricle and ventricle. 14, The left ventricle. +15, The mitral valves. 16, 16, The aorta. 17, The semilunar valves of the +aorta.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +355. Describe the course of the blood from the right auricle in the +heart to the lungs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ If the blood is not changed in the lungs, it will not +flow to the pulmonary veins. This phenomenon is seen in instances of +death from drowning, strangling, carbonic acid, &c. The same is true, +but in a less degree, of individuals whose apparel is tight, as well +as of those who breathe impure air, or have diseased lungs. + +356. The left auricle, (12,) by its contraction, forces the blood into +the left ventricle, (14.) The mitral valves (15) prevent its +reflowing. From the left ventricle the blood is forced into the aorta, +(16,) through which, and its subdivisions, it is distributed to every +part of the system. The semilunar valves (17) prevent its returning. + +_Observation._ The parts of the circulatory organs most liable to +disease are the valves of the heart, particularly the mitral. When +these membranous folds become ossified or ruptured, the blood +regurgitates, and causes great distress in breathing. The operations +of the system are thus disturbed as the movements of the steam engine +would be if its valves were injured, or did not play freely. + +357. The difference between the functions of the pulmonary artery and +aorta is, the former communicates with the right ventricle of the +heart, and distributes only impure blood to the lungs; the other +connects with the left ventricle of the heart, and distributes pure +blood to the whole body, the lungs not excepted. At the extremity of +the divisions of the aorta, as well as the pulmonary artery, are found +capillary vessels. This curious net-work of vessels connects with the +minute veins of the body, which return the blood to the heart. + +_Observation._ The function of the veins of the systemic circulation +is similar to the office of the arteries in the lungs, and that the +veins of the pulmonic circulation transmit to the heart the pure, or +nutrient blood, and thus supply the arteries of the general system +with assimilating fluid. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is the effect when the blood is not changed in the lungs? 356. +Describe the circulation of the blood from the left auricle to the +general system. What part of the circulatory organs is most liable to +disease? What is the effect when the valves are diseased? 357. Give +the difference in the functions of the pulmonary artery and aorta. +Show the relation between the functions of the arteries and veins both +of the pulmonic and systemic circulation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +358. The veins that receive the blood from all parts of the body, +follow nearly the same course as the arteries. The myriads of these +small vessels beneath the skin, and others that accompany the +arteries, at last unite and form two large trunks, called _ve'na ca'va +as-cend'ens_, and _de-scend'ens_. + +_Observation._ A peculiarity is presented in the veins which come from +the stomach, spleen, pancreas, and intestines. After forming a large +trunk, they enter the liver, and ramify like the arteries, and in this +organ they again unite into a trunk, and enter the ascending vein, or +cava, near the heart. This is called the portal circulation. + +359. The ventricles of the heart contract, or the "pulse" beats, about +seventy-five times every minute; in adults; in infants, more than a +hundred times every minute; in old persons, less than seventy-five +times every minute. The energy of the contraction of this organ varies +in different individuals of the same age. It is likewise modified by +the health and tone of the system. It is difficult to estimate the +muscular power of the heart; but, comparing it with other muscles, and +judging from the force with which blood is ejected from a severed +artery, it must be very great. + +_Observation._ The phenomenon known under the name of pulse, is the +motion caused by the pressure of the blood against the coats of the +arteries at each contraction of the ventricles. + +360. The following experiment will demonstrate that the blood flows +from the heart. Apply the fingers upon the artery at the wrist, at +two different points, about two inches apart; if the pressure be +moderately made, the "pulse" will be felt at both points. Let the +point nearest the heart be pressed firmly, and there will be no +pulsation at the lower point; but make strong pressure upon the lower +point only, and the pulsation will continue at the upper point, +proving that the blood flows from the heart, in the arteries, to +different parts of the system. + + -=-=-=-=-=-=-=-=-=-=-=-= + +358. What is the course of the veins? What peculiarity is observable +in the veins of the liver? 359. How often does the heart contract, or +the pulse beat, in adults? In infants? In old persons? What is said of +the energy of its contraction in different persons? How is the pulse +produced? 360. Demonstrate by experiment that the blood flows from the +heart. + + -=-=-=-=-=-=-=-=-=-=-=-= + +361. There are several influences, either separately or combined that +propel the blood from the heart through the arteries, among which may +be named,--1st. The contraction of the muscular walls of the heart. +2d. The contractile and elastic middle coat of the arteries aids the +heart in impelling the blood to the minute vessels of the system. 3d. +The peculiar action of the minute capillary vessels is considered, by +some physiologists, as a motive power in the arterial circulation. +4th. The pressure of the muscles upon the arteries, when in a state of +contraction, is a powerful agent, particularly when they are in active +exercise. + +362. The following experiments will demonstrate that the blood from +every part of the system flows to the heart by the agency of the +veins. 1st. Press firmly on one of the veins upon the back of the +hand, carrying the pressure toward the fingers; for a moment, the vein +will disappear. On removing the pressure of the finger, it will +reappear, from the blood rushing in from below. + +2d. If a tape be tied around the arm above the elbow, the veins below +will become larger and more prominent, and also a greater number will +be brought in view, while the veins above the tape are less distended. +At this time, apply the finger at the wrist, and the pulsation of the +arteries still continues, showing that the blood is constantly flowing +from the heart through the arteries, into the veins; and the +increased size of the veins shows that the pressure of the tape +prevents its flowing back to the heart. + + -=-=-=-=-=-=-=-=-=-=-=-= + +361. State the influences that propel the blood from the heart. 362. +Demonstrate by the first experiment that the blood flows to the heart. +By the second experiment. + + -=-=-=-=-=-=-=-=-=-=-=-= + +363. The influences that return the blood to the heart through the +veins, are not so easily understood as those that act on the blood in +the arteries. Some physiologists have imputed an active propulsive +power to the capillary vessels in carrying the blood through the +veins. This is not easily explained, and perhaps it is as difficult to +understand. An influence upon which others have dwelt, is the suction +power of the heart in active dilatation, acting as a _vis a fronte_ +(power in front) in drawing blood to it. + +364. Another influence that aids the venous circulation is attributed +to the propulsive power of the heart. It is not easy to comprehend how +this power of the heart can be extended through the capillary vessels +to the blood in the veins. Again, an important agency has been found, +by some physiologists, in the inspiratory movements, which are +supposed to draw the blood of the veins into the chest, in order to +supply the vacuum which is created there by the elevation of the ribs +and the descent of the diaphragm. + +365. One of the most powerful causes which influence the venous +circulation, is the frequently-recurring action of the muscles upon +the venous trunks. When the muscles are contracted, they compress that +portion of the veins which lie beneath the swell, and thus force the +blood from one valve to the other, toward the heart. When they are +relaxed, the veins refill, and are compressed by the recurring action +of the muscles. + +_Observation._ The physician, in opening a vein, relies on the +energetic contractions and sudden relaxations of the muscles, when he +directs the patient to clasp the head of a cane, or the arm of a +chair; these alternate motions of the muscles cause an increased flow +of blood to the veins of the ligated arm. + + -=-=-=-=-=-=-=-=-=-=-=-= + +363. What is said of the influences that return the blood to the +heart? What is said of the propulsive power of the capillaries? Of the +suction power of the heart? 364. Give another influence. State another +agency. 365. What is one of the most powerful causes which influence +venous circulation? Give practical observation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 75. An ideal view of the circulation in the lungs and +system. From the right ventricle of the heart, (2,) the dark, impure +blood is forced into the pulmonary artery, (3,) and its branches (4, 5) +carry the blood to the left and right lung. In the capillary vessels (6, +6) of the lungs, the blood becomes pure, or of a red color, and is +returned to the left auricle of the heart, (9,) by the veins, (7, 8.) +From the left auricle the pure blood passes into the left ventricle, +(10.) By a forcible contraction of the left ventricle of the heart, the +blood is thrown into the aorta, (11.) Its branches (12, 13, 13) carry the +pure blood to every organ or part of the body. The divisions and +subdivisions of the aorta terminate in capillary vessels, represented by +14, 14. In these hair-like vessels the blood becomes dark colored, and is +returned to the right auricle of the heart (1) by the vena cava +descendens, (15,) and vena cava ascendens, (16.) The tricuspid valves +(17) prevent the reflow of the blood from the right ventricle to the +right auricle. The semilunar valves (18) prevent the blood passing from +the pulmonary artery to the right ventricle. The mitral valves (19) +prevent the reflow of blood from the left ventricle to the left auricle. +The semilunar valves (20) prevent the reflow of blood from the aorta to +the left ventricle.] + +366. The muscles exercise an agency in maintaining the venous +circulation at a point above what the heart could perform. As the +pulsations are diminished by rest, so they are accelerated by +exercise, and very much quickened by violent effort. There can be +little doubt that the increased rapidity of the return of blood +through the veins, is, of itself, a sufficient cause for the +accelerated movements of the heart during active exercise. + +_Observation._ The quantity of blood in different individuals varies. +From twenty-five to thirty-five pounds may be considered an average +estimate in a healthy adult of medium size. The time in which the +blood courses through the body and returns to the heart, is different +in different individuals. Many writers on physiology unconditionally +limit the period to three minutes. It is undeniable that the size and +health of a person, the condition of the heart, lungs, and brain, the +quantity of the circulating fluid, the amount and character of the +inspired air, and the amount of muscular action, exert a modifying +influence. The time probably varies from three to eight minutes. + + -=-=-=-=-=-=-=-=-=-=-=-= + +366. What causes the accelerated movements of the heart during active +exercise? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Note._ Let the pupil review the anatomy and physiology of the +circulatory organs from fig. 75, or from anatomical outline plates, +No. 6 and 7. + + + + +CHAPTER XIX. + +HYGIENE OF THE CIRCULATORY ORGANS + + +367. If any part of the system is deprived of blood, its vitality will +cease; but, if the blood is lessened in quantity to a limited extent, +only the vigor and health of the part will be impaired. The following +conditions, if observed, will favor the free and regular supply of +blood to all portions of the system. + +368. _The clothing should be loosely worn._ Compression of any kind +impedes the passage of blood through the vessels of the compressed +portion. Hence, no article of apparel should be worn so as to prevent +a free flow of blood through every organ of the body. + +369. The blood which passes to and from the brain, flows through the +vessels of the neck. If the dressing of this part of the body is +close, the circulation will be impeded, and the functions of the brain +will be impaired. This remark is particularly important to scholars, +public speakers, and individuals predisposed to apoplexy, and other +diseases of the brain. + +370. As many of the large veins lie immediately beneath the skin, +through which the blood is returned from the lower extremities, if the +ligatures used to retain the hose, or any other article of apparel, in +proper position, be tight and inelastic, the passage of blood through +these vessels will be obstructed, producing, by their distention, the +varicose, or enlarged veins. Hence elastic bands should always be used +for these purposes. + + -=-=-=-=-=-=-=-=-=-=-=-= + +367-386. _Give the hygiene of the circulatory organs._ 367. What +effect will be produced on the body if it is deprived of blood? If the +blood is only lessened in quantity? 368. Why should the clothing be +worn loose? 369. What is said of dressing the neck? To what persons is +this remark applicable? 370. How are enlarged veins frequently +produced? + + -=-=-=-=-=-=-=-=-=-=-=-= + +371. _An equal temperature of all parts of the system promotes +health._ A chill on one portion of the body diminishes the size of +its circulating vessels, and the blood which should distend and +stimulate the chilled part, will accumulate in other organs. The +deficiency of blood in the chilled portion induces weakness, while the +superabundance of sanguineous fluid may cause disease in another +part of the system. + +372. _The skin should be kept not only of an equal, but at its natural +temperature._ If the skin is not kept warm by adequate clothing, so +that chills shall not produce a contraction of the blood-vessels and a +consequent paleness, the blood will recede from the surface of the +body, and accumulate in the internal organs. Cleanliness of the skin +is likewise necessary, for the reason, that this condition favors the +free action of the cutaneous vessels. + +_Observation._ When intending to ride in a cold day, wash the face, +hands, and feet, in cold water, and rub them smartly with a coarse +towel. This is far better to keep the extremities warm, than to take +spirits into the stomach. + +373. _Exercise promotes the circulation of the blood._ As the action +of the muscles is one of the important agents which propel the blood +through the arteries and veins, daily and regular exercise of the +muscular system is required to sustain a vigorous circulation in the +extremities and skin, and also to maintain a healthy condition of the +system. The best stimulants to improve the sluggish circulation of an +indolent patient, whose skin is pale and whose extremities are cold, +are the union of vigorous muscular exercise with agreeable mental +action, and the systematic application to the skin of cold water, +attended with friction. + + -=-=-=-=-=-=-=-=-=-=-=-= + +371. Why should the temperature of the body be equal? 372. Why should +the skin be kept at its natural, as well as at an equal temperature? +What practical observation when intending to ride in a cold day? 373. +Why does exercise promote health? What are good stimulants for +sluggish circulation in the indolent? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ The coach-driver and teamster throw their arms around +their bodies to warm them when cold. The muscles that are called into +action in swinging the arms, force a greater quantity of blood into +the chilled parts, and consequently, more heat is produced. + +374. When a number of muscles are called into energetic action, a +greater quantity of blood will be propelled to the lungs and heart in +a given time, than when the muscles are in a state of comparative +inaction. It is no uncommon occurrence, that before there is a proper +expansion of the respiratory organs to correspond with the frequency +and energy of the movements of the muscles, there is an accumulation +of blood in the lungs, attended by a painful sensation of fulness and +oppression in the chest, with violent and irregular action of the +heart. This condition of the organs of the chest, called _congestion_, +may be followed by cough, inflammation of the lungs, asthma, and a +structural disease of the heart. + +375. To avoid these sensations and results, when we feel necessitated +to walk or run a considerable distance in a short time, commence the +movements in a moderate manner increasing the speed as the respiratory +movements become more frequent and their expansion more extensive, so +that a sufficient amount of air may be received into the lungs to +purify the increased quantity of blood forced into them. The same +principles should be observed when commencing labor, and in driving +horses and other animals. + +_Observation._ When a large number of muscles are called into action +after repose, as when we rise from a recumbent or sitting posture, +the blood is impelled to the heart with a very strong impetus. If that +organ should be diseased, it may arrive there in larger quantities +than can be disposed of, and death may be the result. Hence the +necessity of avoiding all sudden and violent movements, on the part of +those who have either a functional or structural disease of the +heart. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Mention the illustration. 374. What is the effect when a number of +muscles are called into energetic action? What effect has this +accumulation of blood in the lungs? 375. How can such disagreeable +sensations be avoided? Mention a practical observation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +376. _The mind exercises no inconsiderable influence upon the +circulatory organs._ When an individual is stimulated by hope, or +excited by anger, the heart beats more forcibly, and the arteries act +more energetically, than when a person is influenced by fear, despair, +or sorrow. Consequently, the system is more fully nourished, and +capable of greater exertion, when the former condition obtains, than +when the latter exists. + +377. _The quality and quantity of the blood modify the action of the +heart and blood-vessels._ If this fluid is abundant and pure, the +circulatory vessels act with more energy than when it is deficient in +quantity or defective in quality. + +_Illustrations._ 1st. In an athletic man, whose heart beats forcibly, +and whose pulse is strong, if a considerable quantity of blood is +drawn from a vein, as in bleeding, the heart will beat feebly, and the +pulse will become weak. + +2d. When the blood is made impure by inhaling vitiated air, the action +of the heart and arteries is diminished, which produces an effect +similar to that which takes place when blood is drawn from a vein. + +378. _Hemorrhage from divided arteries should be immediately +arrested._ When large blood-vessels are wounded or cut, the flow of +blood must be immediately stopped, or the person soon faints, and the +heart ceases its action. If it is a large artery that is wounded, the +blood will be thrown out in jets, or jerks, every time the pulse +beats. The flow of blood can be stopped until a surgeon arrives, +either by compressing the vessel between the wound and the heart, or +by compressing the end of the divided artery in the wound. + + -=-=-=-=-=-=-=-=-=-=-=-= + +376. State some of the effects that the mind has on circulation. 377. +What effect have the quantity and quality of blood upon the +circulatory organs? Give illustration 1st. Illustration 2d. 378. What +is necessary when large blood-vessels are wounded or cut? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 76. The track of the large artery of the arm. 1, The +collar-bone. 9, The axillary artery. 10, The brachial artery.] + +[Illustration: Fig. 77. B, The manner of compressing the artery near the +collar-bone. A, The manner of compressing the large artery of the arm, +with the fingers. C, The manner of compressing the divided extremity of +an artery in the wound, with a finger.] + +379. After making compression with the fingers, as described and +illustrated, take a piece of cloth or handkerchief, twist it +cornerwise, and tie a hard knot midway between the two ends. This +knot should be placed over the artery, between the wound and the +heart, and the ends carried around the limb and loosely tied. A stick, +five or six inches long, should be placed under the handkerchief, +which should be twisted until the knot has made sufficient compression +on the artery to allow the removal of the fingers without a return of +bleeding. Continue the compression until a surgeon can be called. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is shown by fig. 76? By fig. 77? 379. What is to be done after +compressing the wound, as before described? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 78. A, B, The track of the large artery of the arm. +The figure exhibits the method of applying the knotted handkerchief to +make compression on this artery.] + +[Illustration: Fig. 79. A, C, The track of the large artery of the thigh. +B, The method of applying the knotted handkerchief to compress this +artery. In practice, the twisting stick B should be placed opposite the +knot over the artery A, C.] + +380. When an artery of the arm is cut, elevating the wounded limb +above the head will tend to arrest the flow of blood. In a wound of a +lower limb, raise the foot, so that it shall be higher than the hip, +until the bleeding ceases. + +_Illustration._ On one occasion, the distinguished Dr. Nathan Smith +was called to a person who had divided one of the large arteries +below the knee. After trying in vain to find the bleeding vessel, so +as to secure it, he caused the foot to be elevated higher than the +hip. At the first instant the blood was forced from the wound about +twelve inches; in a minute, it was diminished to three or four; and, +in a short time, the bleeding ceased. This Dr. S. called his "_great_" +operation; and it was truly great in _simplicity_ and _science_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is shown by fig. 78 and 79? 380. What suggestion relative to the +position of a limb when bleeding? Relate a simple operation by Dr. +Nathan Smith. + + -=-=-=-=-=-=-=-=-=-=-=-= + +381. The practical utility of every person knowing the proper means of +arresting hemorrhage from severed arteries, is illustrated by the +following incidents. In 1848, in the town of N., Mass., a mechanic +divided the femoral artery; although several adult persons were +present, he died in a few minutes from loss of blood, because those +persons were ignorant of the method of compressing severed arteries +until a surgeon could be obtained. + +382. In 1846, a similar accident occurred in the suburbs of +Philadelphia. While the blood was flowing copiously, a lad, who had +received instruction on the treatment of such accidents at the +Philadelphia High School, rushed through the crowd that surrounded the +apparently dying man, placed his finger upon the divided vessel, and +continued the compression until the bleeding artery was secured by a +surgeon. + +383. In "flesh wounds," when no large blood-vessel is divided, wash +the part with cold water, and, when bleeding has ceased, draw the +incision together, and retain it with narrow strips of adhesive +plaster. These should be put on smoothly, and a sufficient number +applied to cover the wound. In most instances of domestic practice, +the strips of adhesive plaster are too wide. They should not exceed in +width one fourth of an inch. Then apply a loose bandage, and avoid +all "healing salves," ointments, and washes. In removing the dressing +from a wound, both ends of the strips of plaster should be raised and +drawn toward the incision. The liability of the wound re-opening is +thus diminished. + + -=-=-=-=-=-=-=-=-=-=-=-= + +381. Relate the first incident showing the utility of every person +knowing the proper method of arresting the flow of blood from divided +arteries. 382. The second incident. 383. How should "flesh wounds" be +dressed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ The union of the divided parts is effected by the +action of the divided blood-vessels, and not by salves and ointments. +The only object of the dressing is to keep the parts together, and +protect the wound from air and impurities. _Nature_, in all cases of +injuries, performs her own cure. Such simple wounds do not generally +require a second dressing and should not be opened until the incisions +are healed. + +[Illustration: Fig. 80. The manner in which strips of adhesive plaster +are applied to wounds.] + +384. In wounds made by pointed instruments, as a nail, or in lacerated +wounds, as those made by forcing a blunt instrument, as a hook, into +the soft parts, there will be no direct and immediate union. In these +cases, apply a soothing poultice, as one made of linseed meal, and +also keep the limb still. It is judicious to consult a physician +immediately, in punctured or lacerated wounds, because they often +induce the most dangerous diseases. + +385. Wounds caused by the bite of rabid animals or venomous serpents, +should be immediately cleansed with pure water. In many instances, +the application of suction, either with "cupping glasses," or the +mouth, will prevent the introduction of the poisonous matter into the +system by absorption. When this is effected, cover the wound with a +soothing poultice, as one made of slippery elm bark. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What should be avoided? How should the strips of plaster be removed +from a wound? How is the union of the divided parts effected? 384. How +should punctured and lacerated wounds be dressed? 385. What is the +treatment of wounds caused by the bite of rabid animals? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Although animal poisons, when introduced into the +circulating fluid through the broken surface of the skin, frequently +cause death, yet they can be taken into the mouth and stomach with +impunity, if the mucous membrane which lines these parts is not +broken. + +[Illustration: Fig. 81. _a_, _a_, Representation of wounds on the back +part of the arm and fore-arm _b_, _b_, Wounds on the anterior part of the +arm and fore-arm. By bending the elbow and wrist, the incisions at _a_, +_a_, are opened, while those at _b_, _b_, are closed. Were the arm +extended at the elbow and wrist, the wounds at _a_, _a_, would be closed, +and those at _b_, _b_, would be opened.] + +386. The proper position of the limbs favors the union of wounds. If +the incision be upon the anterior part of the leg, between the knee +and ankle, extending the knee and bending the ankle will aid its +closing. If it be upon the back part of the leg, by extending the foot +and bending the knee, the gaping of the incision will be diminished. +When wounds occur upon the trunk or upper extremities, let the +position of the person be regarded. + + -=-=-=-=-=-=-=-=-=-=-=-= + +386 Does the proper position of the limbs favor the union of wounds? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XX. + +ABSORPTION. + + +387. ABSORPTION is the process by which the materials of nutrition are +removed from the alimentary canal, to be conveyed into the circulatory +vessels. It is likewise the process by which the particles of matter +that have become injurious, or useless, are removed from the mass of +fluids and solids of which the body is composed. These renovating and +removing processes are performed by two sets of vessels + + +ANATOMY OF THE LYMPHATIC VESSELS. + +388. The vessels that act exclusively for the growth and renovation of +the system, are found only in the alimentary canal. They are called +lacteals. The vessels whose sole function is to remove particles of +matter already deposited, are called _Lym-phat'ics_. The radicles, or +commencement of the veins, in many, and it may be in all parts of the +body, perform the office of absorption. + +_Observation._ This fact accounts for the capacity of the venous +system exceeding the arterial. Had the veins no other function to +perform, beside returning the blood that had been distributed by the +arteries, it would be reasonable to suppose that this system would be +less than the arterial, but the reverse is known to be true. + +389. The LYMPHATIC VESSELS, in structure, resemble the lacteals. They +exist in great numbers in the skin and mucous membranes, particularly +those of the lungs. Though no lymphatics have been traced to the +brain, it is presumed that they exist there, as this part of the body +is not exempt from the composition and decomposition, which are +perpetual in the body. These vessels are extremely minute at their +origin, so that in many parts of the system they cannot be detected +without the aid of a microscope. + + -=-=-=-=-=-=-=-=-=-=-=-= + +387. Define absorption. 388-391. _Give the anatomy of the lymphatic +vessels._ 388. What are those vessels called that act exclusively for +the growth and renovation of the body? Those whose office is to remove +the atoms already deposited? What other vessels perform the office of +absorption? Give observation. 389. Describe the lymphatics. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 82. A single lymphatic vessel, much magnified.] + +[Illustration: Fig. 83. The valves of a lymphatic trunk.] + +[Illustration: Fig. 84. 1, A lymphatic gland with several vessels passing +through it.] + +390. The lymphatic vessels, like the veins, diminish in number as they +increase in size, while pursuing their course toward the large veins +near the heart, into which they pour their contents. The walls of +these vessels have two coats of which the external one is cellular, +and is capable of considerable distention. The internal coat is folded +so as to form valves, like those in the veins. Their walls are so +thin, that these folds give them the appearance of being knotted. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is represented by fig. 82? By fig. 83? By fig. 84? 390. In what +respect do these vessels resemble the veins of the system? Give the +structure of their coats. + + -=-=-=-=-=-=-=-=-=-=-=-= + +391. At certain points, the lymphatic vessels pass through distinct, +soft bodies, peculiar to themselves, which are called _lymphatic +glands_, which are to these vessels what the mesenteric glands are to +the lacteals. The lymphatic glands vary in form and in size. They are +extremely vascular, and appear to consist of a collection of minute +vessels. These glands are found in different parts of the body, but +are most numerous in the groins, axilla, or arm-pits, neck, and +cavities of the chest and abdomen. + +_Observation._ From exposure to cold, these glands are frequently +enlarged and inflamed. They are known under the name of "kernels." +They are often diseased, particularly in scrofula, or "king's evil." + + +PHYSIOLOGY OF THE LYMPHATIC VESSELS. + +392. Though the lacteals and lymphatics resemble each other in their +structure and termination, yet they differ as to the nature of the +fluids which they convey, as well as the nature of their functions. +The lacteals open into the small intestine, and possess the power of +rejecting all substances in the passing aliment, but the chyle. The +lymphatics, on the contrary, not only imbibe all the various +constituents of the body, both fluid and solid, but they sometimes +absorb foreign and extraneous substances, when presented to their +mouths, as in vaccination. + +393. The varieties of absorption are, the _In-ter-sti'tial_, +_Rec-re-men-ti'tial_, _Ex-cre-men-ti'tial_, _Cu-ta'ne-ous_, +_Res-pi'ra-to-ry_, _Ve'nous_, and the _Lac'te-al_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +391. Describe the lymphatic glands. What observation is given in +regard to these glands? 392-403. _Give the physiology of the lymphatic +vessels._ 392. Explain the difference between the lacteals and +lymphatics 393. Name the varieties of absorption. + + -=-=-=-=-=-=-=-=-=-=-=-= + +394. INTERSTITIAL absorption is that change which is constantly going +on in the animal economy among the particles of matter of which every +texture is composed. The ordinary functions of the body, in health, +require incessant action of the lymphatics; the circulatory system, +with its myriads of small vessels, is constantly depositing new atoms +of matter, which become vitalized, and perform a course of actions, +then die, or become useless. These old atoms are removed by the +absorbent system. Thus, wherever there is a minute artery to deposit a +living particle of matter, there is a lymphatic vessel, or venous +radicle, to remove it as soon as it shall have finished its particular +office. + +395. The action of the lymphatic vessels counterbalances those of +nutrition, and thus the form and size of every part of the body is +preserved. When their action exceeds that of the nutrient vessels, the +body emaciates; when it is deficient, plethora is the result. In +youth, they are less active than the nutrient vessels, and the limbs +are plump; but in later periods of life, we find these actions +reversed, and the body diminishes in size. It is not unfrequent that +wens, and other tumors of considerable size, disappear, and even the +entire bone of a limb has been removed from the same general cause. +The effused fluids of bruises are also removed by absorption. + +_Observations._ 1st. When little or no food is taken into the stomach, +life is supported by the lymphatic vessels and veins imbibing the fat +and reconveying it into the blood vessels. It is the removal of this +secretion which causes the emaciation of the face and extremities of a +person recovering from a fever. In consumption, the extreme +attenuation of the limbs is caused by the absorption, not only of the +fat, but also of the muscles and more solid parts of the system. + + -=-=-=-=-=-=-=-=-=-=-=-= + +394. What is interstitial absorption? Flow are the new atoms of matter +deposited? How removed? 395. What vessels do the lymphatics +counterbalance in action? What is the result when their action exceeds +that of the nutrient vessels? When it is less? Mention some instances +of active absorption. What causes the emaciated limbs of a person +recovering from fever? The extreme attenuation in consumption? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. Animals which live in a half torpid state during the winter, +derive their nourishment from the same source. In other words, we may +say the starving animal lives for a time upon itself, eating up, by +internal absorption, such parts of the body as can be spared under +urgent necessity, to feed those organs and continue those functions +that are absolutely essential to life. + +396. RECREMENTITIAL absorption is the removal of those fluids from the +system, which are secreted upon surfaces that have no external outlet. +These fluids are various, as the fat, the marrow, the synovia of +joints, serous fluids, and the humors of the eye. Were it not for this +variety of absorption, dropsy would generally exist in the cavities of +the brain, chest, and abdomen, from the continued action of the +secretory vessels. + +397. EXCREMENTITIAL absorption relates to the fluids which have been +excreted, such as the bile, pancreatic fluid, saliva, milk, and other +secretions. + +398. CUTANEOUS absorption relates to the skin. Here the lymphatic +vessels extend only to the cuticle, which they do not permeate. There +has been much diversity of opinion on the question of cutaneous +absorption; some maintaining that this membrane absorbs, while others +deny it. Many experiments have proved that the skin may absorb +sufficient nutriment to support life for a time, by immersing the +patient in a bath of milk or broth. It has been found that the hand, +immersed to the wrist in warm water, will absorb from ninety to one +hundred grains of fluid in the space of an hour. + +399. Thirst may be quenched by applying moist clothes to the skin, or +by bathing. It is no uncommon occurrence, during a passage from one +continent to the other, for the saliva to become bitter by the +absorption of sea water. Medicinal substances, such as mercury, +morphine, and Spanish flies, are frequently introduced into the system +through the skin. + + -=-=-=-=-=-=-=-=-=-=-=-= + +396. What is recrementitial absorption? 397. Define excrementitial +absorption. 393. To what does cutaneous absorption relate? Is there a +diversity of opinion respecting this variety of absorption? What do +well attested experiments show? 399. What remark in reference to +quenching thirst? What agency conveys medicinal substances and +ointments into the system when tabbed on the skin? + + -=-=-=-=-=-=-=-=-=-=-=-= + +400. RESPIRATORY absorption has reference to the lungs. The mucous +membrane of these organs is abundantly supplied with lymphatic +vessels. By their action, substances finely pulverized, or in the form +of gas, are readily imbibed when inhaled into the lungs, such as +metallic vapors, odoriferous particles, _tobacco smoke_, and other +effluvia. In this way, contagious diseases are frequently contracted. + +_Illustration._ In inhaling sulphuric ether, or letheon, it is +introduced into the vessels of the lungs in the form of vapor, and +through them it is rapidly conveyed to the brain, and thus influences +the nervous system. + +401. VENOUS absorption is the function which the veins perform in +absorbing from the alimentary canal liquids of various kinds that have +been taken into the stomach and are not converted into chyle. In other +parts of the body, they also perform the common office of lymphatics. + +402. LACTEAL, or digestive absorption has reference to the absorption +of chyle only, which is destined for the nutrition of the body. + +403. Absorption is not only very abundant, but generally very rapid, +and all these varieties are maintained through life, except when +suspended by disease. + + -=-=-=-=-=-=-=-=-=-=-=-= + +400. What is said of respiratory absorption? How is letheon introduced +into the system? 401. Define venous absorption. 402. What is lacteal +absorption? 403. What is said of absorption? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 85. A representation of the lymphatic vessels and +glands. 1, 2, 3, 4, 5, 6, The lymphatic vessels and glands of the lower +limbs. 7, Lymphatic glands. 8, The commencement of the thoracic duct. 9, +The lymphatics of the kidney. 10, Of the stomach. 11, Of the liver. 12, +12, Of the lungs. 13, 14, 15, The lymphatics and glands of the arm. 16, +17, 18, Of the face and neck. 19, 20, Large veins. 21, The thoracic duct. +26, The lymphatics of the heart.] + + +HYGIENE OF THE LYMPHATIC VESSELS. + +404. By the action of the lymphatics, substances of an injurious, as +well as of a beneficial, character may be conveyed into the system. +These vessels, under certain conditions, are more active in their +office than at other periods; and it is of practical utility to know +what influences their action. + +405. _The function of these vessels is increased by moisture, and +lessened by an active state of the lacteals._ Observation shows that +the ill-fed, and those persons that live in marshy districts, contract +contagious diseases more readily than those individuals who are well +fed, and breathe a dry and pure air. + +406. _The air of the sick-room should be dry._ If due attention is not +given to ventilation, the clothing of the nurse and patient, together +with the air of the room, will be moistened by the exhalations from +the skin and lungs. This exhalation may contain a poison of greater or +less power, according to its quantity and degree of concentration, and +may be absorbed and reconveyed into the system, causing inflammatory +diseases, and not unfrequently death. + +_Observations._ 1st. When we are attending a sick person a current of +air that has passed over the patient should be avoided. We may +approach with safety very near a person who has an infectious disease, +provided care is taken to keep on the side from which the currents of +air are admitted into the room. + +2d. When we have been visiting or attending on a sick person, it is +judicious to change the apparel worn in the sick-room, and also give +the skin a thorough bathing. The outside garments, also, should be +aired, as poisonous matter may have penetrated the meshes of the +clothing. + + -=-=-=-=-=-=-=-=-=-=-=-= + +404-413. _Give the hygiene of the lymphatic vessels._ 404. What is +said respecting the action of the lymphatic vessels? 405. What +influences the function of these vessels? What does observation show? +406. Why should the air of the sick-room be dry? What suggestion when +we have been visiting or attending on the sick? + + -=-=-=-=-=-=-=-=-=-=-=-= + +407. _The stomach should be supplied with food of a nutrient and +digestible character, in proper quantities, and at stated periods._ +The chyle formed from the food stimulates the lacteals to activity, +which activity is attended with an inactive state of the lymphatics of +the skin and lungs. Thus due attention should be given to the food of +the attendants on the sick, and the members of the family. Before +visiting a sick person it is judicious to take a moderate amount of +nutritious food. + +_Observation._ Many individuals, to prevent contracting disease that +may be communicated from one person to another, use tobacco, either +chewed or smoked; and sometimes alcohol, with decoctions of bitter +herbs. These substances do not diminish, but tend to increase, the +activity of the lymphatics. Thus they make use of the means by which +the poisonous matter formed in the system of the diseased person, may +be more readily conveyed into their own. + +408. _The skin and clothing, as well as the bed-linen, should be +frequently cleansed._ This will remove the poisonous matter that may +be deposited upon the skin and garments, which, if suffered to remain, +might be conveyed into the system by the action of the lymphatics. +This points also to a frequent change of the wearing apparel, as well +as the coverings of the bed. In visiting the unhealthy districts of +the South and West, the liability of contracting disease is much +lessened by taking a supply of food at proper periods, keeping the +skin and clothing in a clean state, the room well ventilated, and +avoiding the damp chills of evening. + +409. _Absorption by the skin is most vigorous when the cuticle is +removed by vesication, or blistering._ Then external applications are +brought into immediate contact with the orifices of the lymphatics of +the skin, and by them rapidly imbibed and circulated through the +system. Thus arsenic applied to the cutaneous vessels, and strong +solutions of opium to extensive burns, have been absorbed in +quantities sufficient to poison the patient. + + -=-=-=-=-=-=-=-=-=-=-=-= + +407. Why should the stomach be supplied with food of a nutrient and +digestible character? What is said of the use of alcohol, or tobacco, +in preventing the introduction of the poisonous matter of contagious +diseases? 408. Why should the clothing and bed-linen be frequently +washed? What suggestion to persons in visiting the unhealthy districts +of the South and West? 409. When is cutaneous absorption most +vigorous? Why? + + -=-=-=-=-=-=-=-=-=-=-=-= + +410. _When the cuticle is only punctured or abraded, poisonous matter +may be introduced into the system._ The highly respected Dr. W., of +Boston, lost his life by poisonous matter from the body of a patient +subjected to a post mortem examination. He had removed from his +finger, previous to the examination, a "hang-nail," and the poison +from the dead body was brought in contact with the denuded part, and +through the agency of the lymphatics it was conveyed into the system. + +411. Puncture any part of the cuticle with the finest instrument that +has upon its point the smallest conceivable quantity of the _vaccine +virus_, or small-pox matter, and it will be brought into contact with +the lymphatic vessels, and through their agency conveyed into the +system. The result is, that persons thus operated upon have the +small-pox, or the vaccine disease. + +412. When we expose ourselves to any poisonous vapors, or handle +diseased animals or sick persons, safety and health require that the +cuticle be not broken or otherwise injured. In many instances, the +poisonous animal matter upon hides has been introduced into the +systems of tanners, through small ulcers upon their fingers or hands. +From these sores there would be seen small red lines extending up the +arm. These swelled tracts indicate an inflammation of the large +lymphatic trunks, that have been irritated and diseased by the +passage of poisonous matter through them into the system. + + -=-=-=-=-=-=-=-=-=-=-=-= + +410. Do the same results follow, if the cuticle is only punctured? +Relate an instance of death by the absorption of poisonous matter. +411. By what means is the vaccine matter introduced into the system? +412. What caution is necessary when we expose ourselves to poisonous +vapors? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ A distressing illustration of the absorption of +deleterious substances from the surface of a sore, is seen in the +favorite experiments of that class of "quacks," who style themselves +"cancer doctors." With them, every trifling and temporary enlargement, +or tumor, is a cancer. Their general remedy is arsenic; and happy is +the unfortunate sufferer who escapes destruction in their hands, for +too frequently their speedy cure is death. + +413. In case of an accidental wound, it is best immediately to bathe +the part thoroughly in pure water, and to avoid all irritating +applications. In some instances, it would be well to apply _lunar +caustic_ immediately. When handling or shrouding dead bodies, or +removing the skin from animals that have died of disease, it would +be well to lubricate the hands with olive-oil or lard. This affords +protection to the minute portions of the skin, from which the cuticle +may be removed. In all cases where there is an ulcer or sore, the +part should be covered with something impervious to fluids, as +court-plaster, before exposing the system to any animal, vegetable, +or mineral poison. + + -=-=-=-=-=-=-=-=-=-=-=-= + +413. What direction is given when the cuticle is broken? What +suggestion is given when shrouding dead bodies? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXI. + +SECRETION. + + +414. In the human body are found many fluids and solids of dissimilar +appearance and character. These are produced by the action of organs, +some of which are of simple structure, while others are very complicated +in their arrangement. These organs are called _Se-cre'to-ry_. + + +ANATOMY OF THE SECRETORY ORGANS. + +415. The SECRETORY ORGANS are the _Ex-ha'lants_, _Fol'li-cles_, and +the _Glands_. + +416. The EXHALANTS were supposed to be terminations of arteries or +capillaries. The external exhalants terminate on the skin and mucous +membranes; the internal in the cellular and medullary tissues. +(Appendix I.) + +[Illustration: Fig. 86. A secretory follicle. An artery is seen, which +supplies the material for its secretion. Follicles are also supplied with +veins and organic nerves.] + +417. The FOLLICLES are small bags, or sacs, situated in the true skin, +and mucous membrane. The pores seen on the skin are the outlets of +these bodies. + + -=-=-=-=-=-=-=-=-=-=-=-= + +414. How are the fluids and solids of the body produced? 415-419. +_Give the anatomy of the secretory organs._ 415. Name the secretory +organs. 416. Describe the exhalants. What is represented by fig. 86? +417. Define follicles. + + -=-=-=-=-=-=-=-=-=-=-=-= + +418. The GLANDS are soft, fleshy organs, and as various in their +structure, as the secretions which it is their function to produce. +Each gland is composed of many small lobules united in a compact mass, +and each lobule communicates by a small duct with the principal +outlet, or duct of the organ. Every gland is supplied with arteries, +veins, lymphatics, and nerves. These, with the ducts, are arranged in +a peculiar manner, and connected by cellular membrane. + +419. There are two classes of glands, one for the modification of the +fluids which pass through them, as the mesenteric and lymphatic +glands; and the other for the secretion of fluids which are either +useful in the animal economy, or require to be rejected from the +body. + +[Illustration: Fig. 87. 1, 1, A secretory gland. 2, 2, Minute ducts that +are spread through the glands. These coalesce to form the main duct, 3.] + + +PHYSIOLOGY OF THE SECRETORY ORGANS. + +420. SECRETION is one of the most obscure and mysterious functions of +the animal economy. "It is that process by which various substances +are separated from the blood, either with or without experiencing any +change during their separation." Not only is the process by which +substances are separated from the blood, called secretion, but the +same term is also applied to substances thus separated. Thus +physiologists say, that by the process of secretion, bile is formed by +the liver; and also, that bile is the secretion of this organ. + + -=-=-=-=-=-=-=-=-=-=-=-= + +418. Give the structure of the glands. 419. How are the glands +arranged? 420-431. _Give the physiology of the secretory organs._ 420. +What is secretion? + + -=-=-=-=-=-=-=-=-=-=-=-= + +421. The secreted fluids do not exist in that form in the blood, +but most of the elements of which they are made do exist in this +fluid, and the "vessels by which it is accomplished may well be called +the architects and chemists of the system; for out of the same +material--the blood--they construct a variety of wonderful fabrics +and chemical compounds. We see the same wonderful power possessed, +also, by vegetables; for out of the same materials the olive prepares +its oil, the cocoa-nut its milk, the cane its sugar, the poppy its +narcotic, the oak its green pulpy leaves, and its dense woody fibre. +All are composed of the same few, simple elements, arranged in +different order and proportions." + +422. "In like manner we find the vessels, in animated bodies, capable +of forming all the various textures and substances which compose the +frame; the cellular tissue, the membranes, the ligaments, the +cartilages, the bones, the marrow, the muscles with their tendons, the +lubricating fluid of the joints, the pulp of the brain, the +transparent jelly of the eye; in short, all the textures of the +various organs of which the body is composed, consist of similar +ultimate elements, and are manufactured from the blood." + +423. Of the agents that produce or direct the different secretions, we +have no very accurate knowledge. Some have supposed this function to +be mechanical, others a chemical process, but experiments prove that +it is dependent on nervous influence. If the nerves are divided which +are distributed to any organ, the process of secretion is suspended. +It is no uncommon occurrence, that the nature of milk will be so +changed from the influence of anger in the mother, as to cause +vomiting, colic, and even convulsions, in the infant that swallows it. +Unexpected intelligence either of a pleasant or unpleasant character, +by its influence on the nervous system, will frequently destroy the +appetite. Sometimes mental agitation, as fear, will cause a cold sweat +to pervade the surface of the body. + + -=-=-=-=-=-=-=-=-=-=-=-= + +421. What is said respecting secreted substances? Do vegetables +possess the property of secretion? 422. From what are the various +textures formed? 423. Have we accurate knowledge of the agents that +produce secretion? + + -=-=-=-=-=-=-=-=-=-=-=-= + +424. Secretions are constantly maintained, during life, from the +serous membrane, by the action of the internal exhalants. The fluid +which is exhaled bears some resemblance to the serum of the blood. Its +use is to furnish the organs, which are surrounded by this membrane, +with a proper degree of moisture, and thus enables them to move easily +on each other, as those within the chest and abdomen. + +425. The cellular tissue exhales a serous fluid, and when it becomes +excessive in quantity, general dropsy is produced. Fat is another +secretion, which is thrown out, in a fluid state, from the cellular +membrane. It is deposited in little cells, and exists in the greatest +abundance between the skin and the muscles. Its use seems to be, to +form a cushion around the body for its protection; to furnish +nutriment for the system when food cannot be taken; to supply the +carbon and hydrogen necessary to sustain the generation of heat, when +these articles of combustion are not otherwise furnished. The +_med'ul-la-ry_ substance, (marrow,) in the cavities of the long bones, +is very much like fat. + +_Observation._ During sickness, if there is not emaciation or +absorption of this secretion, it is considered an unfavorable symptom, +because it indicates a want of power in the absorbing system, which is +among the last to be affected. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is it proved that secretion depends on nervous influence? 424. +What is said of the secretions from the serous membrane? 425. From +what tissue is a serous fluid exhaled? What is the effect when this +fluid becomes excessive in quantity? What is fat? Its use? What is +marrow? + + -=-=-=-=-=-=-=-=-=-=-=-= + +426. The mucous secretion is a transparent, viscid fluid which is +secreted by those membranes that line the cavities of the body, which +have an external communication, as the trachea and alimentary canal. +This secretion serves to protect these parts from the influence of the +air, and concurs, by means of its peculiar properties, in the +performance of their functions. 427. There are two external +secretions, namely, one from the skin, called perspiration, and the +other from the lungs. The cutaneous exhalation, or transpiration[14] +exists in two forms, called sensible perspiration (sweat) and +insensible perspiration. The pulmonary exhalation is the most +important and universal, and closely resembles that of the skin. + + [14] _Transpiration_ is a term often used generically, to signify the + passage of fluids or gases through membranes, internally or + externally; but _perspiration_ is a specific term, signifying + transpiration on to the external surface. + +428. The follicles are found only in the skin and mucous membrane. +They secrete an oily, unctuous substance, which mixes with the +transpiration, and lubricates the skin. At the root of each hair there +is a minute follicle, which secretes the fluid that oils the hair. The +wax in the passage of the ear is secreted from these bodies. + +429. All the blood distributed to the different glands is similar in +composition and character; but the fluids secreted by them, vary in +appearance in a remarkable degree. The office of the glands appears to +be principally to form different secretions. Thus the salivary glands +secrete the insipid saliva; the lachrymal glands, the saline tears; +the liver, the yellow, ropy bile; and the kidneys, the acrid urine. + + -=-=-=-=-=-=-=-=-=-=-=-= + +426. What is said relative to the mucous secretion? 427. Name the +external secretions. 428. Give the office of the follicles. 429. What +appears to be the principal office of the glands? 430. Mention a +secretion produced in a particular emergency. + + -=-=-=-=-=-=-=-=-=-=-=-= + +430. Some secretions are evidently produced only in particular +emergencies, as is seen in the increased secretion of bony matter when +a limb is broken. + +431. When any substance which is not demanded for nutrition, or does +not give nourishment to the system, is imbibed by the lymphatic +vessels, and conveyed into the blood, it is eliminated in the +secretions. + +_Illustration._ A few years since, a poor inebriate was carried to a +London hospital in a state of intoxication. He lived but a few hours. +On examining his brain, nearly half a gill of fluid, strongly +impregnated with gin, was found in the cavities of this organ. This +was secreted from the vessels of the brain. + + +HYGIENE OF THE SECRETORY ORGANS. + +432. _Unless the secretions are regularly maintained, disease will be +the ultimate result._ Let the secretions from the skin be suppressed, +and fever or some internal inflammation will follow. If the bile is +impeded, digestion will be impaired. If any other secretion is +suppressed, it will cause a derangement of the various internal +organs. + +_Observation._ Ardent spirits derange the secretions, and change the +structure of the brain. This is one reason why inebriates do not +generally live to advanced age. + +433. _The quantity of blood influences the character of the +secretions._ If it is lessened to any great extent, the secretions +will be lessened as well as changed in character. + +_Illustration._ When a person has lost a considerable quantity of +blood, there is a sensation of thirst in the fauces, attended with a +cold, pale, dry skin. When reaction comes on, the perspiration is +cold, attended with nausea, and sometimes vomiting. + + -=-=-=-=-=-=-=-=-=-=-=-= + +431. What becomes of those substances imbibed by the lymphatics that +do not give nourishment to the body. 432-437. _Give the hygiene of the +secretory organs._ 432. What effect on the system when the secretions +are not regularly maintained? 433. Does the quantity of blood +influence the secretions? Give an illustration. + + -=-=-=-=-=-=-=-=-=-=-=-= + +434. _The secretory organs require the stimulus of pure blood._ If +this fluid is vitiated, the action of the secretory organs will be +more or less modified. Either the quantity will be affected or the +quality will be altered. + +_Observation._ The impurity of the blood arising from the inhalation +of the vitiated air of sleeping rooms, diminishes and changes the +character of the secretions of the mouth and stomach. This accounts +for the thirst, coated tongue, and disagreeable taste of the mouth +when impure air is breathed during sleep. The disease it induces, is +indigestion or dyspepsia. + +435. _The amount of action modifies the condition of the secretory +organs._ When a secretory organ is excessively stimulated, its vigor +and energy are reduced. The subsequent debility may be so great as to +suppress or destroy its functional power. + +_Illustrations._ 1st. In those sections of the country where flax is +spun on a "foot-wheel," it is not unfrequent that the spinners moisten +the thread with the secretions of the mouth. This seems to operate +economically for a time, but debility of the salivary organs soon +follows, which incapacitates them from supplying saliva sufficient to +moisten the food, producing in a short time disease of the digestive +organs. + +2d. The habit of continual spitting, which attends the chewing of +tobacco and gums, and other substances, between meals, induces +debility, not only of the salivary glands, but of the system +generally. + +436. _One secretory organ may do the office of another._ This +increased action of a secretory organ may be sustained for a limited +time without permanent injury, but, if long continued, a diseased +action of the organ will follow. Of morbid secretions we have examples +in the ossification of the valves of the heart, cancerous and other +tumors. + + -=-=-=-=-=-=-=-=-=-=-=-= + +434. What is the effect of impure blood on the secretory organs? 435. +What results from stimulating excessively a secretory organ? How is +this illustrated? 436. What is the effect when one secretory organ +performs the office of another? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ In the evenings of the warm season, a chill upon the +impressible skin, that suppresses the perspiration, is frequently +followed by a diarrhoea, dysentery, or cholera morbus. These can be +prevented by avoiding the chill. An efficient means of relief, is +immediately to restore the skin to its proper action. + +437. _The secretions are much influenced by the mind._ How this is +effected, it is difficult to explain; but many facts corroborate it. +Every one has felt an increased action of the tear-glands from +distressing feelings. Cheerfulness of disposition and serenity of the +passions are peculiarly favorable to the proper performance of the +secretory function. From this we may learn how important it is to +avoid such things as distract, agitate, or harass us. + +_Observation._ In fevers and other diseases, when the skin, mouth, and +throat are dry from a suppression of the secretions, let the mind of +the patient be changed from despondency to hope, and the skin and the +membrane that lines the mouth and throat will exhibit a more moist +condition, together with a general improvement of the vital organs of +the system. Consequently, all just encouragement of the restoration to +health should be given to a sick person. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give examples of morbid secretions. What is one cause of dysentery and +cholera morbus? How can these affections he relieved? 437. Show the +influence of the mind on the secretions. Mention instances of its +influence. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXII. + +NUTRITION. + + +438. NUTRITION is the vital act by which the different parts of the +body renew the materials of which they are composed. Digestion, +circulation, absorption, and respiration, are but separate links in +the chain of nutrition, which would be destroyed by the absence of any +one of them. + +439. The nutritive process is also a kind of secretion, by which +particles of matter are separated from the blood and conveyed with +wonderful accuracy to the appropriate textures. The function of the +nutrient vessels antagonizes those of absorption: while one system is +constructing, with beautiful precision, the animal frame, the other is +diligently employed in pulling down this complicated structure. + +440. This ever-changing state of the body is shown by giving animals +colored matter, mixed with their food, which in a short time tinges +their bones with the same color as the matter introduced. Let it be +withdrawn, and in a few days the bones will assume their former +color--evidently from the effects of absorption. The changeful state +of the body is further shown by the losses to which it is subjected; +by the necessity of aliment; by the emaciation which follows +abstinence from food. + + -=-=-=-=-=-=-=-=-=-=-=-= + +438-454. _What remarks respecting nutrition?_ 438. What is nutrition? +439. What is said of the nutritive process? The function of the +nutrient vessels? 440. Give a proof of the ever-changing state of the +body. Give other instances illustrative of the changeful state of the +body. + + -=-=-=-=-=-=-=-=-=-=-=-= + +441. Every part of the body is subject to this continual change of +material, yet it is effected with such regularity, that the size, +shape, and appearance, of every organ is preserved; and after an +interval of a few years, there may not remain a particle of matter +which existed in the system at a former period. Notwithstanding this +entire change, the personal identity is never lost. + +442. Many calculations have been made to determine in what length of +time the whole body is renewed. Some have supposed that it is +accomplished in four years; others have fixed the period at seven +years; but the time of the change is not definite, as was supposed by +a genuine son of the Emerald Isle, who had been in America _seven +years and three months_, and consequently maintained that he was a +native American. + +_Observation._ India ink, when introduced into the skin, is not +removed; hence some assert that this tissue is an exception to the +alternate deposition and removal of its atoms. The ink remains because +its particles are too large to be absorbed, and when in the skin it is +insoluble. + +443. "Those animals which are most complicated in their structure, and +are distinguished by the greatest variety of vital manifestations, are +subject to the most rapid changes of matter. Such animals require more +frequent and more abundant supplies of food; and, in proportion as +they are exposed to the greater number of external impressions, will +be the rapidity of this change of matter." + +444. "Animals may be situated so that they lose nothing by secretion; +consequently, they will require no nutriment. Frogs have been taken +from fissures in solid lime rock, which were imbedded many feet below +the surface of the earth, and, on being exposed to the air, exhibited +signs of life." + + -=-=-=-=-=-=-=-=-=-=-=-= + +441. Why is the personal identity never lost in the change of +materials, which is unceasing in the system? 442. Give the opinion of +physiologists respecting the time required for the renewal of the +whole body. What exception to the changing state Of the different +textures? 443. What animals are subject to the most rapid changes of +material? 444. May animals be situated so that they require no +nutriment? What is related of frogs? + + -=-=-=-=-=-=-=-=-=-=-=-= + +445. The renovation of the bone, muscle, ligament, tendon, cartilage, +fat, nerve, hair, &c., is not perfected merely by the general +circulation of the fluid which is expelled from the left side of the +heart, but through the agency of a system of minute vessels, which, +under ordinary circumstances, cannot be seen by the eye, even when +aided by the microscope; still, minute as they are, the function of +these agents is necessary to the continuance of life. They are the +smallest capillary vessels. + +446. "As the blood goes the round of the circulation, the nutrient +capillary vessels select and secrete those parts which are similar to +the nature of the structure, and the other portions pass on; so that +every tissue imbibes and converts to its own use the very principles +which it requires for its growth; or, in other words, as the vital +current approaches each organ, the particles appropriate to it feel +its attractive force,--obey it,--quit the stream,--mingle with the +substance of its tissue,--and are changed into its own true and proper +nature." + +447. Thus, if a bone is broken, a muscle or a nerve wounded, and, if +the system is in a proper state of health, the vital economy +immediately sets about healing the rupture. The blood, which flows +from the wounded vessels, coagulates in the incision, for the double +purpose of stanching the wound, and of forming a matrix for the +regeneration of the parts. Very soon, minute vessels shoot out from +the living parts into the coagulum of the blood, and immediately +commence their operations, and deposit bony matter, where it is +required to unite fractured bones, and nervous substance to heal the +wounded nerve, &c. + + -=-=-=-=-=-=-=-=-=-=-=-= + +445. Show how the renovation of the bones, muscles, &c., is perfected. +446. What is said of the office of the nutrient capillary vessels? +447. When a bone is fractured, by what process is it healed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +448. But the vital economy seems not to possess the power of +reproducing the muscles and true skin, and therefore, when these parts +are wounded, the rupture is repaired by a gelatinous substance, which +gradually becomes hard, and sometimes assumes something of a fibrous +appearance. It so perfectly unites the divided muscle, however, as to +restore its functional power. When the cuticle is removed, it is +reproduced and no scar remains; but, when the true skin is destroyed, +a scar is formed. + +449. It is not uncommon that the nutrient arteries have their action +so much increased in some parts, as to produce preternatural growth. +Sometimes the vessels whose function it is to deposit fat, are +increased in action, and wens of no inferior size are formed. Again, +there may be a deposition of substances unlike any known to exist in +the body. Occasionally, these nutrient arteries of a part take on a +new action, and not only deposit their ordinary substance, but others, +which they have not heretofore secreted, but which are formed by +vessels of other parts of the body. It is in this way that we account +for the bony matter deposited in the valves of the heart and brain, +also the chalky deposits around the finger-joints. + +450. In infancy and childhood, the function of nutrition is very +active; a large amount of food is taken, to supply the place of what +is lost by the action of the absorbents, and also to contribute to the +growth of the body. In middle age, nutrition and absorption are more +equal; but in old age, the absorbents are more active than the +nutrient vessels. The size, consequently, diminishes, the parts become +weaker, the bones more brittle, the body bends forward, and every +function exhibits marks of decay and dissolution. + +451. A striking instance of active absorption in middle age was +exhibited in the person of Calvin Edson, of Vermont, who was exhibited +in the large towns of New England, as the "living skeleton." In early +manhood he was athletic, and weighed one hundred and sixty pounds; but +the excessive action of the absorbents over the nutrient vessels, +reduced his weight, in the interval of eighteen years, to sixty +pounds. + + -=-=-=-=-=-=-=-=-=-=-=-= + +448. What occurs when a muscle is divided? 449. State some of the +results of an increased action of the nutrient arteries. 450. When is +nutrition most active? How in middle age? How in old age? 451. Relate +a striking instance of active absorption in middle age. + + -=-=-=-=-=-=-=-=-=-=-=-= + +452. Instances, on the other hand, have occurred, of the action of the +nutrient vessels exceeding, in an extreme degree, those of absorption; +as in the person of a colored girl, thirteen years of age, who was +exhibited in New York in the summer of 1840. She was of the height of +misses at that age, but weighed five hundred pounds. Several cases are +on record of persons weighing eight hundred pounds. + +453. As already mentioned, the blood is the nutritive fluid of +animals. When this fluid is coagulated, a thick, jelly-like mass +floats in the serum, called coagulum. This coagulated mass is composed +of fibrin, and red globulated matter. The color of the red globules is +owing to the presence of iron, though some physiologists think it +depends on an animal substance of a gelatinous character. + +_Observation._ That portion of the serum which remains fluid after +coagulation by heat has taken place, is called _se-ros'i-ty_. It is +more abundant in the blood of old, than in that of young animals; and +it forms the "red gravy" in roasted meats. + +454. The blood is not necessarily red. It may be white, as in most +fish. There is no animal in which the blood is equally red in all +parts of the body. The ligaments, tendons, and other white tissues in +man are supplied but sparingly with red blood. The fluid that supplies +these tissues is whitish. + + -=-=-=-=-=-=-=-=-=-=-=-= + +452. Of excessive nutrition in early life. 453. Describe the parts +that enter into the composition of the blood. What part of the blood +forms the red gravy in roasted meats? 454. Is the blood necessarily +red? Of what color is the blood of the fish? What part of the human +system has white blood? + + -=-=-=-=-=-=-=-=-=-=-=-= + + +HYGIENE OF NUTRITION. + +455. _Healthy nutrition requires pure blood._ If the nutrient arteries +of the bones are supplied with impure blood, they will become soft or +brittle, their vitality will be impaired, and disease will be the +ultimate result. The five hundred muscles receive another portion of +the blood. These organs are attached to, and act upon the bones. Upon +the health and contractile energy of the muscles depends the ability +to labor. Give these organs of motion impure blood, which is an +unhealthy stimulus, and they will become enfeebled, the step will lose +its elasticity, the movement of the arm will be inefficient, and every +muscle will be incapacitated to perform its usual amount of labor. + +456. When the stomach, liver, and other organs subservient to the +digestion of food, are supplied with impure blood, the digestive +process is impaired, causing faintness and loss of appetite, also a +deranged state of the intestines, and, in general, all the symptoms of +dyspepsia. + +457. The delicate structure of the lungs, in which the blood is or +should be purified, needs the requisite amount of pure blood to give +them vigor and health. When the blood is not of this character, the +lungs themselves lose their tone, and, even if permitted to expand +freely, have not power fully to change the impure quality of this +circulating fluid. + +458. The health and beauty of the skin require that the blood should +be well purified; but, if the arteries of the skin receive vitiated +blood, pimples and blotches appear, and the individual suffers from +"humors." Drinks, made of various kinds of herbs, as well as pills +and powders, are taken for this affection. These will never have the +desired effect, while the causes of impure blood exist. + + -=-=-=-=-=-=-=-=-=-=-=-= + +455-462. _Give the hygiene of nutrition._ 455. What is the effect of +impure blood upon the bones? On the muscles? 456. On the digestive +organs? 457. On the lungs? 458. What is the effect if the vessels of +the skin are supplied with vitiated blood? + + -=-=-=-=-=-=-=-=-=-=-=-= + +459. If the nutrient arteries convey impure material to the brain, the +nervous and bilious headache, confusion of ideas, loss of memory, +impaired intellect, dimness of vision, and dulness of hearing, will be +experienced; and in process of time, the brain becomes disorganized, +and the brittle thread of life is broken. + +_Observations._ 1st. An exertion of any organ beyond its powers, +induces weakness that will disturb the nutrition of the part that is +called into action; and it recovers its energy more slowly in +proportion to the excess of the exertion. The function of the organ +may be totally and permanently destroyed, if the exertion is extremely +violent. We sometimes see palsy produced in a muscle simply by the +effort to raise too great a weight. The sight is impaired, and total +blindness may be produced, by exposure to light too strong or too +constant. The mind may be deranged, or idiocy may follow the excess of +study or the over-tasking of the brain. + +2d. When the function of an organ is permanently impaired or destroyed +by over-exertion, the nutrition of the part is rendered insufficient, +or is entirely arrested; and then the absorbents remove it wholly or +partially, as they do every thing that is no longer useful. Thus, in +palsied patients, a few years after the attack, we often find scarce +any trace of the palsied muscles remaining; they are reduced almost to +simple cellular tissue. The condition of the calf of the leg, in a +person having a club-foot, is a familiar proof of this. + +460. _The blood may be made impure, by the chyle being deficient in +quantity or defective in quality._ This state of the chyle may be +produced by the food being improper in quantity or quality, or by its +being taken in an improper manner, at an improper time, and when the +system is not prepared for it. The remedy for impure blood produced in +any of these ways is to correct the injudicious method of using food. +(See Chapters XV. and XVI.) + + -=-=-=-=-=-=-=-=-=-=-=-= + +459. How does impure blood affect the brain? What is the effect when +any organ is exerted beyond its powers? What is the effect when an +organ is permanently impaired? 460. How may the blood become impure? + + -=-=-=-=-=-=-=-=-=-=-=-= + +461. _The blood may also be rendered impure, by not supplying it with +oxygen in the lungs, and by the carbon not being eliminated from the +system through this channel._ The remedy for "impurities of the +blood," produced in this manner, would be, to carefully reduce to +practice the directions in the chapters on the hygiene of the +respiratory organs, relative to the free movements of the ribs and +diaphragm, and the proper ventilation of rooms. + +462. _A retention of the waste products of the skin produces impure +blood._ When the vessels of the skin, by which the waste, useless +material is eliminated from the system, have become inactive by +improper and inadequate clothing, or by a want of cleanliness, the +dead, injurious atoms of matter are retained in the circulatory +vessels. The only successful method of purifying the blood and +restoring health when this condition exists, is to observe the +directions given relative to clothing and bathing. (See Chapters +XXXIII. and XXXIV.) + +_Observation._ If the blood has become "impure," or "loaded with +humors," (an idea generally prevalent,) it is not and cannot be +"purified" by taking patent pills, powders, drops, &c. But, on the +contrary, by observing the suggestions in the preceding paragraphs, +the blood can be freed of its impurities, and, what is of greater +importance, such "injurious humors" will be prevented. + + -=-=-=-=-=-=-=-=-=-=-=-= + +461. Mention another means by which the blood may be made impure. How +remedied? 462. What is the effect of want of cleanliness upon the +blood? What is said respecting "humors" in the blood? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 88. A front view of the organs within the chest and +abdomen. 1, 1, 1, 1, The muscles of the chest. 2, 2, 2, 2, The ribs. 3, +3, 3, The upper, middle, and lower lobes of the right lung. 4, 4, The +lobes of the left lung. 5, The right ventricle of the heart. 6, The left +ventricle. 7, The right auricle of the heart. 8, The left auricle. 9, The +pulmonary artery. 10, The aorta. 11, The vena cava descendens. 12, The +trachea. 13, The oesophagus. 14, 14, 14, 14, The pleura. 15, 15, 15, The +diaphragm. 16, 16, The right and left lobe of the liver. 17, The +gall-cyst. 18, The stomach. 26, The spleen. 19, 19, The duodenum. 20, The +ascending colon. 21, The transverse colon. 25, The descending colon. 22, +22, 22, 22, The small intestine. 23, 23, The abdominal walls turned down. +24, The thoracic duct, opening into the left subclavian vein, (27.)] + + + + +CHAPTER XXIII. + +THE RESPIRATORY ORGANS. + + +463. The nutrient portion of the food is poured into the left +subclavian vein, (24, 27, fig. 88,) at the lower part of the neck, and +is carried to the right cavities of the heart. The fluid in these +cavities consists of the chyle incorporated with the impure blood. +Neither of these two elements is fitted to promote the growth or +repair the waste of the body. They must be subjected to a process, by +which the first can be converted into blood, and the second freed of +its carbonic acid gas and water. This is effected by the _Respiratory +Organs_. + + +ANATOMY OF THE RESPIRATORY ORGANS. + +464. The RESPIRATORY ORGANS are the _Lungs_, (lights,) the _Tra'che-a_, +(windpipe,) the _Bronch'i-a_, (subdivisions of the trachea,) and the +_Air-Ves'i-cles_, (air-cells at the extremities of the bronchia.) The +_Di'a-phragm_, (midriff,) _Ribs_, and several _Muscles_, also aid in the +respiratory process. + +465. The LUNGS are conical organs, one on each side of the chest, +embracing the heart, (fig. 88,) and separated from each other by a +membranous partition. The color of the lungs is a pinkish gray, +mottled, and variously marked with black. Each lung is divided into +lobes, by a long and deep fissure, which extends from the posterior +surface of the upper part of the organ, downward and forward, nearly +to the anterior angle of the base. In the right lung, the upper lobe +is subdivided by a second fissure. This lung is larger and shorter +than the left. It has three lobes, while the left has only two. + + -=-=-=-=-=-=-=-=-=-=-=-= + +463. What fluids are conveyed into the right cavities of the heart? +What is necessary before they can be adapted to the wants of the body? +By what organs are these changes effected? 464-474. _Give the anatomy +of the respiratory organs._ 464. Name the respiratory organs. What +organs also aid in the respiratory process? 465. Describe the lungs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 89. A back view of the heart and lungs. The posterior +walls of the chest are removed. 1, 2, 3, The upper, middle, and lower +lobes of the right lung. 8, 9, 10, The two lobes of the left lung. 6, 13, +The diaphragm. 7, 7, 14, 14, The pleura that lines the ribs. 4, 11, The +pleura that lines the mediastine. 5, 12, 12, The portion of the pleura +that covers the diaphragm. 15, The trachea, 16, The larynx. 19, 19, The +right and left bronchia. 20, The heart. 29, The lower part of the spinal +column.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 89. + + -=-=-=-=-=-=-=-=-=-=-=-= + +466. Each lung is enclosed, and its structure maintained by a serous +membrane, called the _pleu'ra_, which invests it as far as the root, +and is thence reflected upon the walls of the chest. The lungs, +however, are on the outside of the pleura, in the same way as the head +is on the outside of a cap doubled upon itself. The reflected pleurae +in the middle of the thorax form a partition, which divides the chest +into two cavities. This partition is called the _me-di-as-ti'num_. + +[Illustration: Fig. 90. The heart and lungs removed from the chest, and +the lungs freed from all other attachments. 1, The right auricle of the +heart. 2, The superior vena cava. 3, The inferior vena cava. 4, The right +ventricle. 5, The pulmonary artery issuing from it. _a_, _a_, The +pulmonary artery, (right and left,) entering the lungs. _b_, _b_, +Bronchia, or air-tubes, entering the lungs. _v_, _v_, Pulmonary veins, +issuing from the lungs. 6, The left auricle. 7, The left ventricle. 8, +The aorta. 9, The upper lobe of the left lung. 10, Its lower lobe. 11, +The upper lobe of the right lung. 12, The middle lobe. 13, The lower +lobe.] + +_Observation._ When this membrane that covers the lungs, and also +lines the chest, is inflamed, the disease is called "pleurisy." + + -=-=-=-=-=-=-=-=-=-=-=-= + +466. By what are the lungs enclosed? What is the relative position of +the lungs and pleura? What is said of the reflected pleurae? Explain +fig. 90. What part of the lungs is affected in pleurisy? + + -=-=-=-=-=-=-=-=-=-=-=-= + +467. The lungs are composed of the ramifications of the bronchial +tubes, which terminate in the bronchial cells, (_air-cells_,) +lymphatics, and the divisions of the pulmonary artery and veins. All +of these are connected by cellular tissue, which constitutes the +_pa-ren'chy-ma_. Each lung is retained in its place by its _root_, +which is formed by the pulmonary arteries, pulmonary veins, and +bronchial tubes, together with the bronchial vessels and pulmonary +nerves. + +468. The TRACHEA extends from the larynx, of which it is a continuation, +to the third dorsal vertebra, where it divides into two parts, called +bronchia. It lies anterior to the spinal column, from which it is +separated by the oesophagus. + +469. The BRONCHIA proceed from the bifurcation, or division of the +trachea, to their corresponding lungs. Upon entering the lungs, they +divide into two branches, and each branch divides and subdivides, and +ultimately terminates in small sacs, or cells, of various sizes, from +the twentieth to the hundredth of an inch in diameter. So numerous are +these bronchial or air-cells, that the aggregate extent of their +lining membrane in man has been computed to exceed a surface of 20,000 +square inches, and Munro states that it is thirty times the surface of +the human body. + +_Illustration._ The trachea may be compared to the trunk of a tree; +the bronchia, to two large branches; the subdivisions of the bronchia, +to the branchlets and twigs; the air-cells, to the buds seen on the +twigs in the spring. + +470. The AIR-VESICLES and small bronchial tubes compose the largest +portions of the lungs. These, when once inflated, contain air, under +all circumstances, which renders their specific gravity much less than +water; hence the vulgar term, _lights_, for these organs. The trachea +and bronchial tubes are lined by mucous membrane. The structure of +this membrane is such, that it will bear the presence of pure air +without detriment, but not of other substances. + + -=-=-=-=-=-=-=-=-=-=-=-= + +467. Of what are the lungs composed? How retained in place? 468. Where +is the trachea situated? 469. Describe the bronchia. What is the +aggregate extent of the lining membrane of the air-cells? To what may +the trachea and its branches be compared? 470. What is said of the +air-cells and bronchial tubes? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 91. A representation of the larynx, trachea, +bronchia, and air-cells. 1, 1, 1, An outline of the right lung. 2, 2, 2, +An outline of the left lung. 3, The larynx 4, The trachea. 5, The right +bronchial tube. 6, The left bronchial tube. 7, 7, 7, 8, 8, 8, The +subdivisions of the right and left bronchial tubes. 9, 9, 9, 9, 9, 9, +Air-cells.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +What membrane lines the trachea and its branches? What is peculiar in +its structure? What does fig. 91 represent? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ The structure of the trachea and lungs may be +illustrated, by taking these parts of a calf or sheep and inflating +the air-vesicles by forcing air into the windpipe with a pipe or +quill. The internal structure may then be seen by opening the +different parts. + +471. The lungs, like other portions of the system, are supplied +with nutrient arteries and nerves. The nervous filaments that +are distributed to these organs are in part from the tenth pair, +(par vagum,) that originates in the brain, and in part from the +sympathetic nerve. The muscles that elevate the ribs and the +diaphragm receive nervous fibres from a separate system, which is +called the respiratory. + +[Illustration: Fig. 92. 1, A bronchial tube. 2, 2, 2, Air-vesicles. Both +the tube and vesicles are much magnified. 3, A bronchial tube and +vesicles laid open.] + +_Observation._ When the mucous membrane of a few of the larger +branches of the windpipe is slightly inflamed, it is called a "cold;" +when the inflammation is greater, and extends to the lesser air-tubes, +it is called _bronch-i'tis_. When the air-cells and parenchyma become +inflamed, it is called inflammation of the lungs. Coughing is a +violent expulsory effort by which air is suddenly forced through the +bronchia and trachea to remove offending matter. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How may the structure of the trachea and its branches be illustrated? +471. Are the lungs supplied with nutrient arteries? Where are the +respiratory nerves distributed? From what source do these organs +derive their nervous filaments? + + -=-=-=-=-=-=-=-=-=-=-=-= + +472. The RIBS are joined to the spinal column at their posterior +extremity; and in front, they terminate in cartilages, which unite +them to the sternum. They incline downward, from the spinal column to +the breast-bone, and form resisting walls that assist in producing the +partial vacuum necessary for inspiration. + +[Illustration: Fig. 93. A section of the chest when the lungs are +inflated. 1, The diaphragm. 2, The muscular walls of the abdomen.] + +[Illustration: Fig. 94. A section of the chest when the lungs are +contracted. 1, The diaphragm in common expiration. 2, 2, The muscular +walls of the abdomen. 3, The position of the diaphragm in forced +expiration.] + +These engravings show the diaphragm to be more convex, and the walls +of the abdomen more flattened, when the lungs are collapsed, than when +they are inflated. + +473. The DIAPHRAGM is a flexible circular partition, that separates +the respiratory from the digestive organs, and the chest from the +abdomen. Its margin is attached to the spinal column, the sternum, and +cartilages of the lower ribs. The lungs rest upon its upper surface, +while the liver and stomach are placed below it, (fig. 88.) In a +state of repose, its upper surface forms an arch, the convexity of +which is toward the chest. In forced expiration, its upper point +reaches as high as the fourth rib. In an ordinary inspiration, it is +depressed as low as the seventh rib, which increases the capacity of +the chest. + + -=-=-=-=-=-=-=-=-=-=-=-= + +472. Describe the ribs. Explain figs. 93 and 94. 473. Describe the +diaphragm. + + -=-=-=-=-=-=-=-=-=-=-=-= + +474. The RESPIRATORY muscles are, in general, attached at one +extremity to the parts about the shoulders, head, and upper portion +of the spinal column. From these, they run downward and forward, and +are attached, at the opposite extremity, to the sternum, clavicle, +and upper rib. Other muscles are attached at one extremity to a rib +above, and by the opposite extremity to a rib below. These fill the +spaces between the ribs, and, from their situation, are called +_in-ter-cost'al_ muscles. + +_Observation._ 1st. There are several actions of common occurrence, +that are intimately connected with respiration; such as hiccough, +sneezing, &c. Hiccough is an involuntary contraction of the muscles of +respiration, particularly the diaphragm. + +2d. Sneezing is a violent, involuntary contraction of the respiratory +muscles, as in hiccough. When an acrid stimulant, as snuff, is applied +to the mucous membrane of the nose, an irritation is produced which is +accompanied by a violent expulsion of air from the lungs. This is +owing to the connection between the nasal and respiratory nerves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is its form when not in action? 474. Where do the respiratory +muscles make their attachment? What name is given to those muscles +that fill the places between the ribs? What is hiccough? What is +sneezing? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXIV. + +PHYSIOLOGY OF THE RESPIRATORY ORGANS. + + +475. RESPIRATION, or breathing, is that process by which air is taken +into the lungs and expelled from them. The object of respiration is, +1st. To supply the system with oxygen, which is essential to the +generation of animal heat; 2d. To convert the chyle into blood. This +is done by the oxygen of the inspired air; 3d. To relieve the organs +of the body of the principal elements (carbon and hydrogen) that +compose the old and useless particles of matter. The organs of the +system, as already mentioned, are principally composed of carbon, +hydrogen, oxygen, and nitrogen. + +476. By the action of the lymphatics and capillary veins, the old and +worn-out particles are conveyed into the veins of the systemic +circulation. The hydrogen, in form of watery vapor, is easily +discharged in the perspiration and other secretions. The nitrogen and +oxygen are, or may be, separated from the blood, through the agency of +several different organs; but carbon does not escape so readily. It is +probable that a part of the surplus carbon of the venous blood is +secreted by the liver; but a far greater amount passes to the lungs, +and these may be considered as special organs designed to separate +this element from the venous blood. + +477. An ordinary inspiration may be accomplished by the action of the +diaphragm, and a slight elevation of the ribs. In full inspiration, +the diaphragm is not only more depressed but the ribs are evidently +elevated. To produce this effect on the ribs, two sets of muscles are +called into action. Those which are attached to the upper rib, +sternum, and clavicle, contract and elevate the lower and free +extremities of the ribs. This enlarges the cavity of the chest between +the spinal column and the sternum. But the lateral diameter, in +consequence, is only slightly increased, because the central portion +of the ribs sinks lower than their posterior extremities, or their +cartilaginous attachment to the sternum. + + -=-=-=-=-=-=-=-=-=-=-=-= + +475-494. _Give the physiology of the respiratory organs._ 475. What is +respiration? What is the principal object in breathing? 476. How are +the useless atoms of matter conveyed into the veins of the systemic +circulation? How may the principal elementary substances be separated +from the blood? 477. How may an ordinary inspiration be accomplished? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 95. 6, Four of the vertebrae, to which are attached +three ribs, (7, 7, 7,) with their intercostal muscles, (8, 8.) These +ribs, in their natural position, have their anterior cartilaginous +extremity at 4, while the posterior extremity is attached to the +vertebrae, (6,) which are neither elevated nor depressed in respiration. +1, 1, and 2, 2, parallel lines, within which the ribs lie in their +natural position. If the anterior extremity of the ribs is elevated from +4 to 5, they will not lie within the line 2, 2, but will reach the line +3, 3. If two hands extend from 1, 1, to 2, 2, they will effectually +prevent the elevation of the ribs from 4 to 5, as the line 2, 2, cannot +be moved to 3, 3.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +What effect has a full inspiration on the ribs and diaphragm? How is +the chest enlarged between the spinal column and sternum? What is said +of the lateral diameter of the chest? Explain fig. 95. + + -=-=-=-=-=-=-=-=-=-=-=-= + +478. The central portion of the ribs is raised by the action of +intercostal muscles. The first, or upper rib, has but little movement; +the second has more motion than the first, while the third has still +more than the second. The second rib is elevated by the contraction of +the muscles between it and the first. The third rib is raised by the +action of two sets of muscles; one lies between the first and second +ribs, the other between the second and third. The motion of each +succeeding rib is increased, because it is not only acted upon by the +muscles that move the ribs above, but by an additional intercostal; so +that the movement of the twelfth rib is very free, as it is elevated +by the contraction of eleven muscles. + +479. The tenth rib is raised eight times as much as the second rib, +and the lateral diameter of the lower portion of the chest is +increased in a corresponding degree. At the same time, the muscular +margin of the diaphragm contracts, which depresses its central +portion; and in this way, the chest is enlarged forward, laterally, +and downward, simultaneously with the relaxation of the walls of the +abdomen. + +480. The lungs follow the variations of capacity in the chest, +expanding their air-cells when the latter is enlarged, and contracting +when the chest is diminished. Thus, when the chest is expanded, the +lungs follow, and consequently a vacuum is produced in their +air-cells. The air then rushes through the mouth and nose into the +trachea and its branches, and fills the vacuum as fast as it is made. +This mechanical process constitutes _inspiration_. + +481. After the expansion of the chest, the muscles that elevated the +ribs relax, together with the diaphragm. The elasticity of the +cartilages of the ribs depresses them, and the cavity of the chest is +diminished, attended by the expulsion of a portion of the air from the +lungs. At the same time, the muscles that form the front walls of the +abdominal cavity, contract, and press the alimentary canal, stomach, +and liver, upward against the diaphragm; this, being relaxed, yields +to the pressure, rises upward, and presses upon the lungs, which +retreat before it, and another portion of air is expelled from these +organs. This process is called _expiration_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +478. Describe the action of the intercostal muscles upon the ribs. +479. How does the elevation of the tenth rib compare with the second? +What effect has this elevation upon the lateral diameter of the chest? +480. Describe the process of inspiration. 481. Describe the process by +which the air is forced out of the lungs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 96. A front view of the chest and abdomen in +respiration. 1, 1, The position of the walls of the chest in inspiration. +2, 2, 2, The position of the diaphragm in inspiration. 3, 3, The position +of the walls of the chest in expiration. 4, 4, 4, The position of the +diaphragm in expiration. 5, 5, The position of the walls of the abdomen +in inspiration. 6, 6, The position of the abdominal walls in expiration.] + +482. Thus it is obvious that the enlargement of the chest, or +inspiration, is produced in two ways: 1st. By the depression of the +convex portion of the diaphragm; 2d. By the elevation of the ribs. On +the contrary, the contraction of the chest, or expiration, is +produced by the depression of the ribs, and elevation of the central +part of the diaphragm. These movements are successive during life, and +constitute _respiration_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 96. 482. In how many ways may the chest be enlarged, and +how is it accomplished? How is the contraction of the chest effected? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 97. A side view of the chest and abdomen in +respiration. 1, The cavity of the chest. 2, The cavity of the abdomen. 3, +The line of direction for the diaphragm when relaxed in expiration. 4, +The line of direction for the diaphragm when contracted in inspiration. +5, 6, The position of the front walls of the chest and abdomen in +inspiration. 7, 8, The position of the front walls of the abdomen and +chest in expiration.] + +_Experiment._ Place the ear upon the chest of a person, and a +murmuring sound will be heard, somewhat like the soft sighings of the +wind through forest trees. This sound is caused by the air rushing in +and out of the lungs, and is peculiarly distinct in the child. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 97. How may the murmur of respiration be heard? + + -=-=-=-=-=-=-=-=-=-=-=-= + +483. It is not easy to decide how much air is taken into the lungs at +each inspiration. The quantity, however, must vary in different +individuals, from the difference in the condition and expansion of the +lungs, together with the size of the chest. From numerous experiments, +the quantity, at an ordinary inspiration, of a common-sized man, is +fixed at forty cubic inches. It has been estimated that one hundred +and seventy cubic inches can be thrown out of the lungs by a forcible +expiration, and that there remain in the lungs two hundred and twenty +cubic inches; so that these organs, in their quiescent state, may be +considered as containing about three hundred and ninety cubic inches +of air, or more than a gallon. + +484. Respiration is more frequent in females and children than in +adult men. In diseases, particularly those of the lungs, it is more +increased in frequency than the action of the heart. In health, the +smallest number of inspirations in a minute by an adult, is not less +than fourteen, and they rarely exceed twenty-five. Eighteen may be +considered an average number. The quantity of oxygen taken into the +lungs at each inspiration is about eight cubic inches, one half of +which disappears in every act of respiration. + +_Observation._ Under different circumstances, however, the consumption +of oxygen varies. It is greater when the temperature is low, than when +it is high; and during digestion the consumption has been found one +half greater than when the stomach was empty. + + -=-=-=-=-=-=-=-=-=-=-=-= + +483. Can it be ascertained with accuracy how much air is taken into +the lungs at each inspiration? Why not? What is the probable quantity +that an ordinary sized man inspires? How much can be thrown out of the +lungs at a forcible expiration, and how much remains in the lungs? +From these calculations, how much may they contain in their quiescent +state? 484. In whom is respiration most frequent? How in disease? How +in health? How many may be considered an average number? When is the +consumption of oxygen the greatest? + + -=-=-=-=-=-=-=-=-=-=-=-= + +485. Dr. Southwood Smith has lately performed a series of very +interesting experiments, from which he deduces the following general +results: "1st. The volume of air ordinarily present in the lungs is +about twelve pints. 2d. The volume of air received by the lungs at an +ordinary inspiration is one pint. 3d. The volume of air expelled from +the lungs at an ordinary expiration, is a little less than one pint. +4th. Of the volume of air received by the lungs at one inspiration, +only one fourth part is decomposed at one action of the heart. 5th. +The quantity of blood that flows to the lungs, to be acted upon by the +air at one action of the heart, is two ounces, and this is acted on in +less than one second of time. 6th. The quantity of blood in the whole +body of the human adult, is twenty-five pounds avoirdupois, or twenty +pints. 7th. In the mutual action that takes place between the air and +blood, every twenty-four hours, the air loses thirty-seven ounces of +oxygen, and the blood fourteen ounces of carbon." + +486. Apparently, atmospheric air is a simple element. But chemical +analysis shows its composition to be oxygen and nitrogen, in the +proportion of twenty-one parts of the former, and about seventy-nine +of the latter. In addition, there is a small amount of vapor of water +and carbonic acid. The pressure of this invisible, elastic fluid upon +the body of an ordinary sized adult, is estimated to equal thirty-five +thousand pounds. + +487. The principal substance of a vitiated character in the +dark-colored blood is carbonic acid. And since there is no chemical +affinity between the oxygen and nitrogen of the air, the former +readily unites with some of the elements of the blood. Hence, whenever +blood is presented to the air in the lungs, the oxygen leaves the +nitrogen, and becomes mixed with the circulating fluid. (Appendix J.) + + -=-=-=-=-=-=-=-=-=-=-=-= + +485. State the 1st, 2d, 3d, and 4th deductions from the experiments of +Dr. Southwood Smith. The 5th, 6th, and 7th. 486. Of what is +atmospheric air composed? What is the weight of air upon a common +sized man? 487. What is the principal substance of a vitiated +character in the dark-colored blood? What is said of the chemical +affinity between oxygen and nitrogen? + + -=-=-=-=-=-=-=-=-=-=-=-= + +488. Again, carbonic acid and water have a stronger affinity for +atmospheric air than for the other elements of the blood. Consequently, +when they are brought into contact with the air in the lungs, the +carbonic acid and water leave the other constituents of the blood, and +unite with the air. In this way the bluish, or impure blood is +relieved of its impurities, and becomes the red, or pure blood, +which contains the principles so essential to life. (Appendix K.) + +489. The formation of carbonic acid and water, eliminated from the +system through the lungs and skin, is explained by the following +theory: In the lungs and upon the skin the oxygen separates from the +nitrogen and unites with the blood in the capillary vessels of these +organs. The oxygen is conveyed with the blood to the capillary +arteries and veins of the different tissues of the system. In these +membranes there is a chemical union of the oxygen with the carbon and +hydrogen contained in the blood and waste atoms of the system. This +combustion, or union of oxygen with carbon and hydrogen, is attended +with the disengagement of heat, and the formation of carbonic acid and +water. (Appendix L.) + +490. The following experiment will illustrate the passage of fluids +through membranes, and the different affinity of gases for each other. +Put a mixture of water and alcohol into a phial and leave it uncorked. +Both the water and alcohol have a greater affinity for air than for +each other. Alcohol has a greater affinity for the air, and will be +diffused through it more readily than the water, when there is no +intervening obstacle. But tie a piece of bladder over the mouth of the +phial, and let it stand a few days,--the water will leave the +alcohol, and pass through the membrane. By the aid of this experiment, +we shall endeavor to explain the interchange of fluids in the lungs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +488. What is formed when oxygen unites with carbon or hydrogen? 489. +Give the theory for the formation of carbonic acid and watery vapor +thrown out of the system. 490. Illustrate the passage of fluids +through membranes, and the different affinities of gases. + + -=-=-=-=-=-=-=-=-=-=-=-= + +491. The walls of the air-vesicles, and coats of the blood-vessels, +are similar, in their mechanical arrangement, to the membranous +bladder in the before described experiment. As the oxygen of the air +has greater affinity for blood than for nitrogen, so it permeates the +membranes that intervene between the air and blood more readily than +the nitrogen. As the carbonic acid and water have a greater affinity +for air than for the other elements of the blood, so they will also +pass through the walls of the blood-vessels and air-cells more readily +than the other elements of the dark-colored blood. + +[Illustration: Fig. 98. 1, A bronchial tube divided into three branches. +2, 2, 2, Air-cells. 3, Branches of the pulmonary artery, that spread over +the air-cells. Through the pulmonary artery the dark, impure blood is +carried to the air-cells of the lungs. 4, Branches of the pulmonary vein, +that commence at the minute terminations of the pulmonary artery. Through +the pulmonary vein the red blood is returned to the heart.] + +492. As the impure blood is passing in the minute vessels over the +air-cells, the oxygen passes through the thin coats of the air-cells +and blood-vessels, and unites with the blood. At the same time, the +carbonic acid and water leave the blood, and pass through the coats of +the blood-vessels and air-cells, and mix with the air in the cells. +These are thrown out of the system every time we breathe. This +interchange of products produces the change in the color of the +blood. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Explain fig. 98. 492. How and where is the blood changed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Experiment._ Fill a bladder with dark blood drawn from any animal. +Tie the bladder closely, and suspend it in the air. In a few hours, +the blood next to the membrane will have become of a bright red color. +This is owing to the oxygen from the air passing through the bladder, +and uniting with the blood, while the carbonic acid has escaped +through the membrane. + +[Illustration: Fig. 99. An ideal view of the pulmonary circulation. 1, 1, +The right lung. 2, 2, The left lung. 3, The trachea. 4, The right +bronchial tube. 5, The left bronchial tube. 6, 6, 6, 6, Air-cells. 7, The +right auricle. 8, The right ventricle. 9, The tricuspid valves. 10, The +pulmonary artery. 11, The branch to the right lung. 12, The branch to the +left lung. 13, The right pulmonary vein. 14, The left pulmonary vein. 15, +The left auricle. 16, The left ventricle. 17, The mitral valves.] + +493. The presence of carbonic acid and watery vapor in the expired +air, can be proved by the following experiments: 1st. Breathe into +lime-water, and in a few minutes it will become of a milk-white color. +This is owing to the carbonic acid of the breath uniting with the +lime, forming the _carbonate of lime_. 2d. Breathe upon a cold, dry +mirror for a few minutes, and it will be covered with moisture. This +is condensed vapor from the lungs. In warm weather, this watery vapor +is invisible in the expired air, but in a cold, dry morning in winter, +the successive jets of vapor issuing from the mouth and nose are +sufficiently obvious. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give the experiment showing that oxygen changes the dark-colored blood +to a bright red color. What is represented by fig. 99? 493. How can +the presence of carbonic acid in the lungs be proved? + + -=-=-=-=-=-=-=-=-=-=-=-= + +494. From the lungs are eliminated other impurities beside carbonic +acid, the perceptible quality of which is various in different +persons. The offensive breath of many persons may be caused by decayed +teeth, or the particles of food that may be retained between them, but +it often proceeds from the secretion, in the lungs, of certain +substances which previously existed in the system. + +_Illustration._ When spirituous liquors are taken into the stomach, +they are absorbed by the veins and mixed with the dark-colored blood, +in which they are carried to the lungs to be expelled from the body. +This will explain the fact, which is familiar to most persons, that +the odor of different substances is perceptible in the breath, or +expired air, long after the mouth is free from these substances. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How the watery vapor? 494. Are there other excretions from the lungs? +Give the illustration. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Note._ Let the anatomy and physiology of the respiratory organs be +reviewed from figs. 96, 97, and 99, or from anatomical outline plates +Nos. 5 and 7. + + + + +CHAPTER XXV. + +HYGIENE OF THE RESPIRATORY ORGANS. + + +495. For man to enjoy the highest degree of health, it is necessary +that the impure "venous" blood be properly changed. As this is +effected in the lungs by the action of the air, it follows that this +element, when breathed, should be pure, or contain twenty-one per +cent. of oxygen to about seventy-nine per cent. of nitrogen. + +496. The volume of air expelled from the lungs is somewhat less than +that which is inspired. The amount of loss varies under different +circumstances. An eightieth part of the volume taken into the lungs, +or half a cubic inch, may be considered an average estimate. + +497. _The quality and purity of the air is affected by every +respiration._ 1st. The quantity of oxygen is diminished. 2d. The +amount of carbonic acid is increased. 3d. A certain proportion of +watery vapor is ejected from the lungs in the expired air. Of the +twenty-one parts of oxygen in the inspired air, only eighteen parts +are expired, while the carbonic acid and watery vapor are increased +about four per cent. The quantity of nitrogen is nearly the same in +the expired as in the inspired air. + +_Observation._ It is now fully ascertained that while the chemical +composition of the blood is essentially changed, its weight remains +the same, as the carbon and hydrogen discharged are equal to the +united weight of the oxygen and nitrogen absorbed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +495-546. _Give the hygiene of the respiratory organs._ 495. What is +necessary that man enjoy the highest degree of health? 496. How does +the volume Of expired air compare with that which was inspired? Does +this loss vary, and what is an average estimate? 497. How is the +purity of the air affected by respiration? How is the inhaled oxygen +affected? What effect on the carbonic acid and watery vapor? On the +nitrogen? What is said respecting the weight of the blood? + + -=-=-=-=-=-=-=-=-=-=-=-= + +498. If one fourth part of the volume of air received by the lungs at +one inspiration is decomposed at one "beat" of the heart, it might be +supposed that if the expired air be again received into the lungs, one +half of the oxygen would be consumed, and, in a similar ratio, if +re-breathed four times, all the oxygen would be consumed. But it does +not follow, if the air is thus re-breathed, that the same changes will +be effected in the lungs. For air that has been inspired does not part +with its remaining oxygen as freely as when it contains the proper +amount of this life-giving element, and thus the changes in the impure +blood are not so completely effected. + +_Illustration._ In the process of dyeing, each successive article +immersed in the dye weakens it; but it does not follow that the dye +each time is affected in the same degree, or that the coloring matter +by repeated immersions can be wholly extracted. The same principle +applies to the exchange of oxygen and carbonic acid gas in the lungs. + +499. _If the inspired air is free from moisture and carbonic acid, +these substances contained in the blood will be more readily imparted +to it._ When the air is loaded with vapor, they are removed more +slowly; but if it is saturated with moisture, no vapor will escape +from the blood through the agency of the lungs. This may be +illustrated by the following experiment: Take two and a half pounds of +water, add to it half a pound of common salt, (chloride of sodium,) +and it will readily mix with the water; and to this solution add the +same quantity of salt, and it will be dissolved more slowly. Again, +add more salt, and it will remain undissolved, as the water has become +saturated by the pound before dissolved. + + -=-=-=-=-=-=-=-=-=-=-=-= + +498. Does air that is re-breathed freely impart its oxygen? Why? 499. +What is the effect on the blood when the air is free from vapor and +carbonic acid? When loaded with vapor? When saturated? How is this +illustrated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +500. The principle in this experiment is analogous to that of the +union between carbonic gas and atmospheric air. Allen and Pepy showed +by experiment, that air which had been once breathed, contained eight +and a half per cent. of carbonic acid. They likewise showed, that no +continuance of the respiration of the same air could make it take up +more than ten per cent. This is the point of saturation. + +_Experiment._ Sink a glass jar that has a stop-cock, or one with a +glass stopper, into a pail of water, until the air is expelled from +the jar. Fill the lungs with air, and retain it in the chest a short +time, and then breathe into the jar, and instantly close the +stop-cock. Close the opening of the jar that is under the water with a +piece of paper laid on a plate of sufficient size to cover the +opening, invert the jar, and sink into it a lighted candle. The flame +will be extinguished as quickly as if put in water.[15] Remove the +carbonic acid by inverting the jar, and place a lighted candle in it, +and the flame will be as clear as when out of the jar. + + [15] As a substitute for a jar with a stop-cock, take a piece of lead + pipe bent in the form of a siphon, and insert it in the mouth + of a reversed jar. This experiment is as conclusive whether the + air is inhaled once only or breathed many times. + +_Observations._ 1st. It is familiarly known that a taper will not burn +where carbonic acid exists in any considerable quantity, or when there +is a marked deficiency of oxygen. From this originated the judicious +practice of sinking a lighted candle into a well or pit before +descending into it. If the flame is extinguished, respiration cannot +there be maintained, and life would be sacrificed should a person +venture in, until the noxious air is removed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +500. What did the experiments of Allen and Pepy show? How can the +presence of carbonic gas in the expired air be demonstrated? State +observation 1st. Observation 2d. + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. It is the action of carbonic acid upon the respiratory organs, +that gives rise to a phenomenon frequently seen in mines and caves. A +man may enter these subterranean rooms, and feel no inconvenience in +breathing; but the dog that follows him, falls apparently dead, and +soon dies if not speedily removed to pure air. This arises from the +fact that this gas is heavier than air, and sinks to the bottom of the +room or cave. + +3d. While it is true that carbonic acid possesses properties that +render it unfit to be breathed, it is, notwithstanding, productive of +very agreeable effects, when conveyed into the stomach. It forms the +sparkling property of mineral waters, and fills the bubbles that rise +when beer or cider is fermenting. + +501. _Pure atmospheric air is best adapted to a healthy action of the +system._ As the air cannot be maintained pure under all circumstances, +the question may be asked, To what degree may the air be vitiated and +still sustain life? and what is the smallest quantity of pure air a +person needs each minute to maintain good health? Birnan says, that +air which contains more than three and a half per cent. of carbonic +acid is unfit for respiration, and, as air once respired contains +eight and a half per cent. of carbonic acid, it clearly shows that it +is not fitted to be breathed again. + +502. No physiologist pretends that less than seven cubic feet of air +are adequate for a man to breathe each minute, while Dr. Reid allows +ten feet. The necessity of fifteen or twenty times the amount of air +actually taken into the lungs, arises from the circumstance, that the +expired air mixes with and vitiates the surrounding element that has +not been inhaled. + +503. _The quantity of air which different persons actually need, +varies._ The demand is modified by the size, age, habits, and +condition of the body. A person of great size who has a large quantity +of blood, requires more air than a small man with a less amount of +circulating fluid. Individuals whose labor is active, require more air +than sedentary or idle persons, because the waste of the system is +greater. On the same principle, the gormandizer needs more of this +element than the person of abstemious habits. So does the growing lad +require more air than an adult of the same weight, for the reason that +he consumes more food than a person of mature years. Habit also exerts +a controlling influence. A man who works in the open air suffers more +when placed in a small, unventilated room, than one who is accustomed +to breathe the confined air of workshops. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Observation 3d. 501. What questions may be asked respecting the +inspired air? Give the remark of Birnan. 502. How many cubic feet of +air are adequate for a man to breathe each minute? How much does Dr. +Reid allow? 503. Mention some reasons why different persons do not +require the same amount of air. + + -=-=-=-=-=-=-=-=-=-=-=-= + +504. _Air, in which lamps will not burn with brilliancy, is unfitted +for respiration._ In crowded rooms, which are not ventilated, the air +is vitiated, not only by the abstraction of oxygen and the deposition +of carbonic acid, but by the excretions from the skin and lungs of the +audience. The lamps, under such circumstances, emit but a feeble +light. Let the oxygen gas be more and more expended, and the lamps +will burn more and more feebly, until they are extinguished. + +_Illustrations._ 1st. The effects of breathing the same air again and +again, are well illustrated by an incident that occurred in one of our +halls of learning. A large audience had assembled in an ill-ventilated +room, to listen to a lecture; soon the lamps burned so dimly that the +speaker and audience were nearly enveloped in darkness. The +oppression, dizziness, and faintness experienced by many of the +audience induced them to leave, and in a few minutes after, the lamps +were observed to rekindle, owing to the exchange of pure air on +opening the door. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is it with the laborer? With the gormandizer? With the person that +works in the open air? 504. What effect has impure air on a burning +lamp? Give the illustration of the effects of impure air on lighted +lamps. + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. In the "Black Hole of Calcutta," one hundred and forty-six +Englishmen were shut up in a room eighteen feet square, with only two +small windows on the same side to admit air. On opening this dungeon, +ten hours after their imprisonment, only twenty-three were alive. The +others had died from breathing impure air. + +505. _Air that has become impure from the abstraction of oxygen, an +excess of carbonic acid, or the excretions from the lungs and skin, +has a deleterious effect on the body._ When this element is vitiated +from the preceding causes, it prevents the proper arterialization, or +change in the blood. For this reason, pure air should be admitted +freely and constantly into work-shops and dwelling-houses, and the +vitiated air permitted to escape. This is of greater importance than +the warming of these apartments. We can compensate for the deficiency +of a stove, by an extra garment or an increased quantity of food; but +neither garment, exercise, nor food will compensate for pure air. + +506. _School-rooms should be ventilated._ If they are not, the pupils +will be restless, and complain of languor and headache. Those +unpleasant sensations are caused by a want of pure air, to give an +adequate supply of oxygen to the lungs. When pupils breathe for a +series of years such vitiated air, their life is undoubtedly +shortened, by giving rise to consumption and other fatal diseases. + +_Illustration._ A school-room thirty feet square and eight feet high, +contains 7200 cubic feet of air. This room will seat sixty pupils, +and, allowing ten cubic feet of air to each pupil per minute, all the +air in the room will be vitiated in twelve minutes. + +_Observation._ In all school-rooms where there is not adequate +ventilation, it is advisable to have a recess of five or ten minutes +each hour. During this time, let the pupils breathe fresh air, and +open the doors and windows, so that the air of the room shall be +completely changed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Of the effects of breathing impure air. 505. In preserving health, +what is of greater importance than warming the room? 506. Why should a +school-room be ventilated? Give the illustration. + + -=-=-=-=-=-=-=-=-=-=-=-= + +507. _Churches, concert halls, and all rooms designed for a collection +of individuals, should be amply ventilated._ While the architect and +workmen are assiduous in giving these public rooms architectural +beauty and splendor, by adorning the ceiling with Gothic tracery, +rearing richly carved columns, and providing carefully for the warming +of the room, it too frequently happens that no direct provision is +made for the change of that element which gives us beauty, strength, +and life. + +_Illustration._ A hall sixty feet by forty, and fifteen feet high, +contains 36,000 cubic feet of air. A hall of this size will seat four +hundred persons; by allowing ten cubic feet of air to each person per +minute, the air of the room will be rendered unfit for respiration in +nine minutes. + +508. _Railroad cars, cabins of steam and canal-boats, omnibuses, and +stage-coaches, require ample ventilation._ In the construction of +these public conveyances, too frequently, the only apparent design is, +to seat the greatest number of persons, regardless of the quantity and +character of the air to maintain health and even life. The character +of the air is only realized when, from the fresh, pure air, we enter a +crowded cabin of a boat or a closed coach; then the vitiated air from +animal excretions and noxious gases is offensive, and frequently +produces sickness. + +509. The influence of habit is strikingly expressed by Birnan, in the +"Art of Warming and Ventilating Rooms:" "Not the least remarkable +example of the power of habit is its reconciling us to practices +which, but for its influence, would be considered noxious and +disgusting. We instinctively shun approach to the dirty, the squalid, +and the diseased, and use no garment that may have been worn by +another. We open sewers for matters that offend the sight or the +smell, and contaminate the air. We carefully remove impurities from +what we eat and drink, filter turbid water, and fastidiously avoid +drinking from a cup that may have been pressed to the lips of a +friend. On the other hand, we resort to places of assembly, and draw +into our mouths air loaded with effluvia from the lungs, skin, and +clothing of every individual in the promiscuous crowd--exhalations +offensive, to a certain extent, from the most healthy individuals; but +when arising from a living mass of skin and lungs, in all stages of +evaporation, disease, and putridity,--prevented by the walls and +ceiling from escaping--they are, when thus concentrated, in the +highest degree deleterious and loathsome." + + -=-=-=-=-=-=-=-=-=-=-=-= + +What suggestion when a school-room is not ventilated? 507. What is +said in regard to ventilating churches, concert halls, &c.? State the +illustration. 508. What remarks relative to public conveyances? 509. +State the influence of habit by Birnan. + + -=-=-=-=-=-=-=-=-=-=-=-= + +510. _The sleeping-room should be so ventilated that the air in the +morning will be as pure as when retiring to rest in the evening._ +Ventilation of the room would prevent morning headaches, the want of +appetite, and languor--so common among the feeble. The impure air of +sleeping-rooms probably causes more deaths than intemperance. Look +around the country, and those who are most exposed, who live in huts +but little superior to the sheds that shelter the farmer's flocks, are +found to be the most healthy and robust. Headaches, liver complaints, +coughs, and a multitude of nervous affections, are almost unknown to +them; not so with those who spend their days and nights in rooms in +which the sashes of the windows are calked, or perchance doubled, to +prevent the keen but healthy air of winter from entering their +apartments. Disease and suffering are their constant companions. + + -=-=-=-=-=-=-=-=-=-=-=-= + +510. What is said of the ventilation of sleeping-rooms? What would +adequate ventilation prevent? Give a common observation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ By many, sleeping apartments twelve feet square and +seven feet high, are considered spacious for two persons, and good +accommodations for four to lodge in. An apartment of this size +contains 1008 cubic feet of air. Allowing ten cubic feet to each +person per minute, two occupants would vitiate the air of the room in +fifty minutes, and four in twenty-five minutes. When lodging-rooms are +not ventilated, we would strongly recommend early rising. + +511. _The sick-room, particularly, should be so arranged that the +impure air may escape, and pure air be constantly admitted into the +room._ It is no unusual practice in some communities, when a child or +an adult is sick of an acute disease, to prevent the ingress of pure +air, simply from the apprehension of the attendants, that the patient +will contract a cold. Again, the prevalent custom of several +individuals sitting in the sick-room, particularly when they remain +there for several hours, tends to vitiate the air, and, consequently, +to increase the suffering and danger of the sick person. In fevers or +inflammatory diseases of any kind, let the patient breathe pure air; +for the purer the blood, the greater the power of the system to remove +disease, and the less the liability to contract colds. + +_Observation._ Among children, convulsions, or "fits," usually occur +when they are sleeping. In many instances, these are produced by the +impure air which is breathed. To prevent these alarming and +distressing convulsions, the sleeping-room should be ventilated, and +there should be no curtains around the bed, or coverings over the +face, as they produce an effect similar to that experienced when +sleeping in a small, unventilated room. To relieve a child when +convulsed, carry it into the open air. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is said of the size of sleeping-rooms? 511. What is said of the +sick-room? Mention some prevailing customs in reference to these +rooms. What is said of convulsions among children? + + -=-=-=-=-=-=-=-=-=-=-=-= + +512. _While occupying a room, we are insensible of the gradual +vitiation of the air._ This is the result of the diminished +sensibility of the nervous system, and gradual adaptation of the +organs to blood of a less stimulating character. This condition is +well illustrated in the hibernating animals. We are insensible of the +impure air of unventilated sleeping-rooms, until we leave them for a +walk or ride. If they have been closed, we are made sensible of the +character of the air as soon as we reenter them, for the system has +regained its usual sensibility while inhaling a purer atmosphere. + +513. _In the construction of every inhabited room, there should be +adequate means of ventilation, as well as warming._ No room is well +ventilated, unless as much pure air is brought into it as the +occupants vitiate at every respiration. This can be effected by making +an aperture in the ceiling of the room, or by constructing a +ventilating flue in the chimney. This should be in contact with the +flues for the escape of smoke, but separated from them by a thin brick +partition. The hot air in the smoke flues will warm the separating +brick partition, and consequently rarefy the air in the ventilating +flue. Communication from every room in a house should be had to such +flues. The draught of air can be regulated by well-adjusted registers, +which in large rooms should be placed near the floor as well as near +the ceiling. + +514. While provision is made for the escape of rarefied impure air, we +should also provide means by which pure air may be constantly admitted +into the room, as the crevices of the doors and windows are not always +sufficient; and, if they should be adequate, air can be introduced in +a more convenient, economical, and appropriate manner. There should be +an aperture opposite the ventilating flue, at or near the floor, to +connect with the outer walls of the building or external air. But if +pure heated air is introduced into the room, it obviates the necessity +of the introduction of the external air.[16] + + [16] Mr. Frederick Emerson, of Boston, has devised a simple and + effective apparatus for removing vitiated air from a room. It + is successfully used upon all the public school-houses of + Boston. It is now being generally applied to the school-houses + and other public buildings, as well as private dwellings, of + New England. + + -=-=-=-=-=-=-=-=-=-=-=-= + +512. Why are we insensible to the gradual vitiation of the air of an +unventilated room? 513. What is very important in the building of +every inhabited room? How can a room be well ventilated? 514. What is +said relative to a communication with the external air? + + -=-=-=-=-=-=-=-=-=-=-=-= + +515. In warming rooms, the hot air furnaces, or box and air-tight +stoves converted into hot air furnaces, should be used in preference +to the ordinary stoves. The air thus introduced into the room is pure +as well as warm. In the adaptation of furnaces to dwelling-houses, +&c., it is necessary that the air should pass over an ample surface of +iron moderately heated; as a red heat abstracts the oxygen from the +contiguous air, and thus renders it unfit to be respired.[17] + + [17] Dr. Wyman's valuable work on "Ventilation," and the work of Henry + Barnard, Esq., on "School-house architecture," can be + advantageously consulted, as they give the practical methods of + ventilating and warming shops, school-rooms, dwelling-houses, + public halls, &c. + +_Observation_. Domestic animals need a supply of pure air as well as +man. The cows of cities, that breathe a vitiated air, have, very +generally, tubercles. Sheep that are shut in a confined air, die of a +disease called the "rot," which is of a tuberculous character. +Interest and humanity require that the buildings for animals be +properly ventilated. + + -=-=-=-=-=-=-=-=-=-=-=-= + +515. How should rooms be warmed? What is necessary in the adaptation +of furnaces to dwelling-houses? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXVI. + +HYGIENE OF THE RESPIRATORY ORGANS, CONTINUED. + + +516. The change that is effected in the blood while passing through +the lungs, not only depends upon the purity of the air, but the amount +inspired. The quantity varies according to the size of the chest, and +the movement of the ribs and diaphragm. + +517. _The size of the chest and lungs can be reduced by moderate and +continued pressure._ This is most easily done in infancy, when the +cartilages and ribs are very pliant; yet it can be effected at more +advanced periods of life, even after the chest is fully developed. For +want of knowledge of the pliant character of the cartilages and ribs +in infants, too many mothers, unintentionally, contract their chests, +and thus sow the seeds of disease by the close dressing of their +offspring. + +518. If slight but steady pressure be continued from day to day and +from week to week, the ribs will continue to yield more and more, and +after the expiration of a few months, the chest will become diminished +in size. This will be effected without any suffering of a marked +character; but the general health and strength will be impaired. It is +not the violent and ephemeral pressure, but the moderate and +protracted, that produces the miscalled, "genteel," contracted +chests. + +519. The style of dress which at the present day is almost universal, +is a prolific cause of this deformity. These baneful fashions are +copied from the periodicals, so widely circulated, containing a +"fashion plate of the latest fashions, from Paris." In every instance; +the contracted, deformed, and, as it is called, lady-like waist, is +portrayed in all its fascinating loveliness. These periodicals are +found on almost every centre-table, and exercise an influence almost +omnipotent. If the plates which corrupt the morals are excluded by +civil legislation, with the same propriety ought not those to be +suppressed that have a tendency so adverse to health? + + -=-=-=-=-=-=-=-=-=-=-=-= + +516. What varies the amount of air received into the lungs? 517. How +can the size of the chest be diminished? When is this most easily +effected? 518. How are the miscalled, "genteel," contracted chests +usually produced? 519. What is said of the style of the dress at the +present day? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 100. A correct outline of the Venus de Medici, the +beau ideal of female symmetry.] + +[Illustration: Fig. 101. An outline of a well-corseted modern beauty. + +One has an artificial, insect waist; the other, a natural +waist. One has sloping shoulders, while the shoulders of the other are +comparatively elevated, square, and angular. The proportion of the +corseted female below the waist, is also a departure from the symmetry of +nature.] + +_Observations._ 1st. The Chinese, by compressing the feet of female +children, prevent their growth; so that the foot of a _Chinese belle_ +is not larger than the foot of an American girl of five years. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does fig. 100 represent? Fig. 101? Give observation 1st. + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. The American women _compress their chests_, to prevent their +growth; so that the chest of an _American belle_ is not larger than +the chest of a Chinese girl of five years. Which country, in this +respect, exhibits the greater intelligence? + +3d. The chest can be deformed by making the linings of the waists of +the dresses tight, as well as by corsets. Tight vests, upon the same +principle, are also injurious. + +520. In children, who have never worn close garments, the circumference +of the chest is generally about equal to that of the body at the hips; +and similar proportions would exist through life, if there were no +improper pressure of the clothing. This is true of the laboring +women of the Emerald Isle, and other countries of Europe, and in the +Indian female, whose blanket allows the free expansion of the chest. The +symmetrical statues of ancient sculptors bear little resemblance to +the "beau ideal" of American notions of elegant form. This perverted +taste is in opposition to the laws of nature. The design of the human +chest is not simply to connect the upper and lower portions of the +body, like some insects, but to form a case for the protection of the +vital organs. + +521. _Individuals may have small chests from birth._ This, to the +particular individual, is natural; yet it is adverse to the great and +general law of Nature relative to the size of the human chest. Like +produces like, is a general law of the animal and vegetable kingdoms. +No fact is better established, than that which proves the hereditary +transmission from parents to children of a constitutional liability +to disease and the same may be said in regard to their conformations. +If the mother has a small, taper waist, either hereditary or acquired, +this form may be impressed on her offspring;--thus illustrating the +truthfulness of scripture, "that the sins of the parents shall be +visited upon the children unto the third and fourth generation." + + -=-=-=-=-=-=-=-=-=-=-=-= + +Observation 2d. Observation 3d. 520. What is the size of the chest of +a child that has always worn loose clothing? What is said of the size +of the laboring women of Ireland, and the Indian female? How is it in +ancient statues? What is the design of the chest? 521. What is a +general law of both the animal and vegetable kingdoms? What fact in +this connection is well established? + + -=-=-=-=-=-=-=-=-=-=-=-= + +522. _The quantity of air inhaled is modified by the capacity of the +respiratory organs._ The necessity of voluminous lungs may he +elucidated by the following experiment: Suppose a gill of alcohol, +mixed with a gill of water, be put into a vessel having a square foot +of surface, and over the vessel a membrane be tied, and that the water +will evaporate in twenty-four hours. If the surface had been only six +inches square, only one fourth of the water would have evaporated +through the membrane in the given time. If the surface had been +extended to two square feet, the water would have evaporated in twelve +hours. + +523. Apply this principle to the lungs: suppose there are two hundred +feet of carbonic acid to be carried out of the system every +twenty-four hours. This gas, in that time, will pass through a +vesicular membrane of two thousand square feet. If the lungs were +diminished in size, so that there would be only one thousand square +feet of vesicular membrane, the amount of carbonic acid would not, and +could not, be eliminated from the system. Under such circumstances, +the blood would not be purified. + +524. Again; suppose the two thousand square feet of membrane would +transmit two hundred cubic feet of oxygen into the system every +twenty-four hours. If it should be diminished one half, this amount of +oxygen would not pass into the blood. From the above illustrations we +may learn the importance of well-developed chests and voluminous +lungs; for, by increasing the size of the lungs, the oxygen is more +abundantly supplied to the blood, and this fluid is more perfectly +deprived of its carbon and hydrogen. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does this hereditary transmission prove? 522. How is the +necessity of voluminous lungs illustrated? 525. How is this principle +applied to the interchange of products in the lungs? + + -=-=-=-=-=-=-=-=-=-=-=-= + +525. The chest is not only most expanded at its lower part, but the +portion of the lungs that occupies this space of the thoracic cavity +contains the greater part of the air-cells; and, from the lower two +thirds of the lungs the greatest amount of carbonic acid is abstracted +from the blood, and the greatest amount of oxygen gas is conveyed into +the circulating fluid. Hence, contracting the lower ribs is far more +injurious to the health than diminishing the size of the upper part of +the chest. + +526. The question is often asked, Can the size of the chest and the +volume of the lungs be increased, when they have been injudiciously +compressed, or have inherited this unnatural form? The answer is in +the affirmative. The means for attaining this end are, a judicious +exercise of the lungs, by walking in the open air, reading aloud, +singing, sitting erect, and fully inflating the lungs at each act of +inspiration. If the exercise be properly managed and persevered in, it +will expand the chest, and give tone and health to the important +organs contained in it. But, if the exercise be ill-timed or carried +to excess, the beneficial results sought will probably not be +attained. + +_Observation._ Scholars, and persons who sit much of the time, should +frequently, during the day, breathe full and deep, so that the +smallest air-cells may be fully filled with air. While exercising the +lungs, the shoulders should be thrown back and the head held erect. + +527. _The movement of the ribs and diaphragm is modified by the +dress._ When the lungs are properly filled with air, the chest is +enlarged in every direction. If any article of apparel is worn so +tight as to prevent the full expansion of the chest and abdomen, the +lungs, in consequence, do not receive air sufficient to purify the +blood. The effect of firm, unyielding clothing, when worn tight, in +preventing a due supply of air to the lungs, may be shown by the +following illustration. + + -=-=-=-=-=-=-=-=-=-=-=-= + +525. Why is it more injurious to contract the lower part of the chest +than the upper? 526. How can the size of the chest be increased when +it is contracted? Give the observation. 527. How is the movement of +the ribs and diaphragm modified? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ If the diameter of a circle is three feet, the +circumference will be nine feet. If the diameter is extended to four +feet, the circumference will be increased to twelve feet. Should a +tight band be thrown around a circle of nine feet, its diameter cannot +be increased, for the circumference cannot be enlarged. + +528. Any inelastic band, drawn closely around the lower part of the +chest, or the abdomen, below the ribs, operates like the band in the +preceding illustration, in restricting the movement of the ribs. When +any article of dress encircles either the chest or abdomen, so as to +prevent an increase of its circumference, it has an injudicious +tendency, as it prevents the introduction of air in sufficient +quantities to purify the blood. The question is not, How much +restriction of the respiratory movements can be endured, and life +continue? but, Does any part of the apparel restrict the movements? If +it does, it is a violation of the organic laws; and though Nature is +profuse in her expenditures, yet sooner or later, she sums up her +account. + +529. In determining whether the apparel is worn too tight, inflate the +lungs, and, if no pressure is felt, no injurious effects need be +apprehended from this cause. In testing the tightness of the dress, +some persons will contract to the utmost the abdominal muscles, and +thus diminish the size of the chest, by depressing the ribs; when +this is done, the individual exclaims, "How loose my dress is!" This +practice is both deceptive and ludicrous. A good test is, to put the +hand on the chest below the arm; if there is no movement of the ribs +during respiration, the apparel is too tight. The only reliable test, +however, is a full inflation of the lungs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is the effect of unyielding clothing, when worn tight, illustrated? +528. What effect has an inelastic band upon the lower part of the +chest? What question is asked? 529. How can we determine whether the +apparel is worn too tight? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Many individuals do not realize the small amount of +force that will prevent the enlargement of the chest. This can be +demonstrated by drawing a piece of tape tightly around the lower part +of the chest of a vigorous adult, and confining it with the thumb and +finger. Then endeavor fully to inflate the lungs, and the movement of +the ribs will be much restricted. + +530. _The position in standing and sitting influences the movement of +the ribs and diaphragm._ When the shoulders are thrown back, and when +a person stands or sits erect, the diaphragm and ribs have more +freedom of motion, and the abdominal muscles act more efficiently; +thus the lungs have broader range of movement than when the shoulders +incline forward, and the body is stooping. + +531. _Habit exercises an influence upon the range of the respiratory +movements._ A person who has been habituated to dress loosely, and +whose inspirations are full and free, suffers more from the tightness +of a vest or waistband, than one, the range of movements of whose +chest has long been subjected to tight lacing. + +532. _The condition of the brain exercises a great influence upon +respiration._ If the brain is diseased, or the mind depressed by +grief, tormented by anxiety, or absorbed by abstract thought, the +contractile energy of the diaphragm and muscles that elevate the +ribs, is much diminished, and the lungs are not so fully inflated, as +when the mind is influenced by joy or other exhilarating emotions. The +depressing passions likewise lessen the frequency of respiration. By +the influence of these causes, the blood is but partially purified, +and the whole system becomes enfeebled. Here we may see the admirable +harmony between the different parts of the body, and the adaptation of +all the functions to each other. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give another test. How can the amount of pressure necessary to prevent +the enlargement of the chest be demonstrated? 530. Show the effect of +position on the movements of the ribs and diaphragm. 531. Show the +effect of habit on the respiratory movements. 532. State the influence +of the mind upon respiration. + + -=-=-=-=-=-=-=-=-=-=-=-= + +533. As the quantity of air inhaled at each unimpeded inspiration in +lungs of ample size, is about forty cubic inches, it follows, if the +movement of the ribs and diaphragm is restricted by an enfeebled +action of the respiratory muscles, or by any other means, the blood +will not be perfectly purified. In the experiment, (Sec. 522, 523,) +suppose forty cubic inches of air must pass over the membrane twenty +times every minute, and that this is the amount required to remove the +vapor which arises from the membrane; if only half of this amount of +air be supplied each minute, only one half as much water will be +removed from the alcohol through the membrane in twenty-four hours; +consequently, the alcohol would be impure from the water not being +entirely removed. + +534. Restrain the elevation of the ribs and depression of the +diaphragm, so that the quantity of air conveyed into the lungs will be +reduced to twenty cubic inches, when forty are needed, and the results +will be as follows: Only one half of the carbonic acid will be +eliminated from the system, and the blood will receive but one half as +much oxygen as it requires. This fluid will then be imperfectly +oxydated, and partially freed of its impurities. The impure blood will +be returned to the left side of the heart, and the whole system will +suffer from an infringement of organic laws. + + -=-=-=-=-=-=-=-=-=-=-=-= + +533. Illustrate the effect upon the blood when the respiratory muscles +are enfeebled in their action. 534. Show how the blood is imperfectly +purified by restricting the movements of the ribs and diaphragm. + + -=-=-=-=-=-=-=-=-=-=-=-= + +535. _Scrofula, or consumption, frequently succeeds a depressed state +of the nervous system._ These diseases arise from the deposition of +tuberculous matter in different parts of the body. Those individuals +who have met with reverses of fortune, in which character and property +were lost, afford painful examples. Hundreds yearly die from the +effect of depressed spirits, caused by disappointed hopes, or +disappointed ambition. + +_Illustration._ A striking instance of the effects of mental +depression is related by Laennec. In a female religious establishment +in France, great austerities were practised; the mind was absorbed in +contemplating the terrible truths of religion, and in mortifying the +flesh. The whole establishment, in the space of ten years, was +several times depopulated--with the exception of the persons +employed at the gate, in the kitchen, and garden--with that fatal +disease, consumption. This institution did not long continue, but +was suppressed by order of the French government. + +536. _The purity of the blood is influenced by the condition of the +lungs._ When the bronchial tubes and air-cells have become partially +impervious to air, from pressure upon the lungs, from fluids in the +chest, from tumors, or from the consolidation of the cells and tubes +from disease,--as inflammation, or the deposition of yellow, cheesy +matter, called tubercles,--the blood will not be purified, even if the +air is pure, the lungs voluminous, and the respiratory movements +unrestricted, as the air cannot permeate the air-cells. + +_Observations._ 1st. The twenty-three who escaped immediate death in +the Black Hole of Calcutta were soon attacked with inflammation of the +lungs, by which these organs were consolidated, and thus prevented +the permeation of air into their cells. This disease of the lungs was +caused by breathing vitiated air. + + -=-=-=-=-=-=-=-=-=-=-=-= + +535. Mention some of the effects of mental depression upon the body. +What is related by Laennec? 536. Does the condition of the lungs +influence the purity of the blood? Mention some of the conditions that +will impede the oxydation of blood in the lungs. What occurred to +those persons who escaped death in the Black Hole of Calcutta? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. One of the precursory symptoms of consumption is the feeble murmur +of respiration in the upper part of the lungs. This condition of these +organs is produced by, or frequently follows, mental depression, the +breathing of impure air, the stooping position in standing or sitting, +and the restriction of the movements of the ribs and diaphragm. + +3d. Persons asphyxiated by carbonic acid, water, strangling, or any +noxious air, after resuscitation, are usually affected with coughs and +other diseases of the lungs. + +537. COLDS and COUGHS are generally induced by a chill, that produces +a contraction of the blood-vessels of the skin; and the waste +material, which should be carried from the body by the agency of the +vessels of this membrane, is retained in the system, and a great +portion of it is returned to the mucous membrane of the lungs. For +such is the harmony established by the Creator, that if the function +of any portion of the body is deranged, those organs whose offices are +similar take on an increased action. + +538. The waste material, that should have passed through the many +outlets of the skin, creates an unusual fulness of the minute vessels +that nourish the mucous membrane of the bronchia; this induces an +irritation of these vessels, which increases the flow of blood to the +nutrient arteries of the lungs. There is, also, a thickening of the +lining membrane of the lungs, caused by the repletion of the bronchial +vessels of the mucous membrane; this impedes the passage of air +through the small bronchial tubes, and consequently the air-vesicles +cannot impart a sufficient quantity of oxygen to purify the blood, and +this fluid, imperfectly purified, does not pass with facility through +the lungs. An additional obstacle to the free passage of air into the +lungs, is the accumulation of blood in the pulmonary vessels. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is one of the precursory symptoms of consumption? How is this +condition frequently produced? What diseases usually follow asphyxia +by carbonic acid, water, strangling, &c.? 537. How are colds generally +induced? 538. What effect has a common cold upon the mucous membrane +of the lungs? + + -=-=-=-=-=-=-=-=-=-=-=-= + +539. As colds and coughs are very generally treated by the "matrons" +of the community, or by the patient, the following suggestions may aid +in directing a proper treatment: To effect a speedy cure, it is +necessary to diminish the amount of fluid in the vessels of the lungs. +This can be effected in two ways: 1st. By diminishing the quantity of +blood in the system; 2d. By diverting it from the lungs to the skin. +The first condition can be easily and safely affected, by abstaining +from food, and drinking no more than a gill of fluid in twenty-four +hours. As there is a continuous waste from the skin and other organs +of the system, the quantity of blood by this procedure will be +diminished, and the lungs relieved of the accumulated fluid. + +540. The second condition can be accomplished by resorting to the warm +or vapor bath. These and the common sweats will invite the blood from +the lungs to the skin. By keeping up the action of the skin for a few +hours, the lungs will be relieved. In some instances, emetics and +cathartics are necessary; mucilages, as gum arabic or slippery-elm +bark, would be good. After the system is relieved, the skin is more +impressible to cold, and consequently requires careful protection by +clothing. In good constitutions, the first method is preferable, and +generally sufficient without any medicine or "sweating." + +541. _The method of resuscitating persons apparently drowned._ In the +first instance, it is necessary to press the chest, suddenly and +forcibly, downward and backward, and instantly discontinue the +pressure. Repeat this without intermission, until a pair of bellows +can be procured. When the bellows are obtained, introduce the nozzle +well upon the base of the tongue, and surround the mouth and nose with +a towel or handkerchief, to close them. Let another person press upon +the projecting part of the neck, called "Adam's apple," while air is +introduced into the lungs through the bellows. Then press upon the +chest, to force the air from the lungs, to imitate natural breathing. +(Appendix M.) + + -=-=-=-=-=-=-=-=-=-=-=-= + +539. Give the first method for the treatment of cold. 540. The second +method. 541, 542. How should persons apparently drowned be treated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +542. Continue the use of the bellows, and forcing the air out of the +chest, for an hour at least, unless signs of natural breathing come +on. Wrap the body in warm, dry blankets, and place it near the fire, +to preserve the natural warmth, as well as to impart artificial heat. +Every thing, however, is secondary to filling the lungs with air. +Avoid all friction until breathing is restored. Send immediately for +medical aid. + +543. _The means of resuscitating persons asphyxiated from electricity, +&c._ In apparent death from electricity, (lightning,) the person is +frequently asphyxiated from _pa-ral'y-sis_ (palsy) of the respiratory +muscles. To recover such persons, resort to artificial respiration. In +cases of apparent death from hanging or strangling, the knot should be +untied or cut immediately; then use artificial respiration, or +breathing, as directed in apparent death from drowning. + +_Observation._ It is an impression, in many sections of the country, +that the law will not allow the removal of the cord from the neck of a +body found suspended, unless the coroner be present. It is therefore +proper to say, that no such delay is necessary, and that no time +should be lost in attempting to resuscitate the strangled person. + +544. _The method of resuscitating persons apparently dead from +inhaling carbonic acid gas._ When life is apparently extinct from +breathing carbonic acid gas, the person should be carried into the +open air. The head and shoulders should be slightly elevated; the face +and chest should be sponged or sprinkled with cold water, or cold +vinegar and water, while the limbs are wrapped in dry, warm blankets. +In this, as in asphyxia from other causes, immediately resort to +artificial respiration. + + -=-=-=-=-=-=-=-=-=-=-=-= + +543. What treatment should be adopted in asphyxia from electricity? +From hanging? 544. What should be the treatment in asphyxia from +inhaling carbonic acid gas? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observations._ 1st. Many persons have died from breathing carbonic +acid that was formed by burning charcoal in an open pan or portable +furnace, for the purpose of warming their, sleeping-rooms. This is not +only produced by burning charcoal, but is evolved from the live coals +of a wood fire; and being heavier than air, it settles on the floor of +the room; and, if there is no open door or chimney-draught, it will +accumulate, and, rising above the head of an individual, will cause +asphyxia or death. + +2d. In resuscitating persons apparently dead from causes already +mentioned, if a pair of bellows cannot be procured immediately, let +their lungs be inflated by air expelled from the lungs of some person +present. To have the expired air as pure as possible, the person +should quickly inflate his lungs, and instantly expel the air into +those of the asphyxiated person. _Place the patient in pure air, admit +attendants only into the apartment, and send for a physician without +delay._ + + -=-=-=-=-=-=-=-=-=-=-=-= + +What sad results frequently follow the burning of charcoal in a closed +room? What suggestion in resuscitating asphyxiated persons? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXVII. + +ANIMAL HEAT. + + +545. The true sources of animal heat, or calorification, are still +imperfectly known. No hypothesis has, as yet, received the concurrent +assent of physiologists. We see certain phenomena, but the ultimate +causes are hidden from our view. Its regular production, to a certain +degree, is essential both to animal and vegetable life. + +546. There is a tendency between bodies of different temperature to an +equilibrium of heat. Thus, if we touch or approach a hot body, the +heat, or caloric passes from that body to our organs of feeling, and +gives the sensation of heat. On the contrary, when we touch a cold +body, the heat passes from the hand to that body, and causes a +sensation of cold. + +547. The greater number of animals appear cold when we touch them; +and, indeed, the temperature of their bodies is not much above that of +the atmosphere, and changes with it. In man, and other animals that +approach him in their organization, it is otherwise. They have the +faculty of producing a sufficient quantity of caloric to maintain +their temperatures nearly at the same degree, under all atmospheric +changes, and keep themselves warm. + +548. Those animals whose proper heat is not very perceivable, are +called _cold_-blooded; as most species of fishes, toads, snakes, +turtles, and reptiles generally. Those animals which produce +sufficient heat independently of the atmosphere surrounding them, are +called _warm_-blooded; as man, birds, quadrupeds, &c. + + -=-=-=-=-=-=-=-=-=-=-=-= + +545-570. _What is said respecting animal heat?_ 545. Are the true +sources of animal heat known? What do we see? 546. What is the tendency +between bodies of different temperatures? Give an explanation. 547. +What is said of the temperature of animals? 548. What is meant by +cold-blooded animals? By warm-blooded animals? + + -=-=-=-=-=-=-=-=-=-=-=-= + +549. The temperature of man is about 98 deg., (Fahrenheit's thermometer,) +and that of some other animals is higher; the temperature of birds, +for example, is about 110 deg. It is obvious, that in most parts of the +globe, the heat of the atmosphere is, even in summer, less than that +of the human body. In our latitude, the mercury rarely attains 98 deg., +and sometimes it descends to several degrees below zero. + +550. Captain Parry, with his ship's company, in his voyage of +discovery to the arctic regions, wintered in a climate where the +mercury was at 40 deg., and sometimes at 55 deg. below zero. Captain Back +found it 70 deg. below zero. These were 72 deg. and 102 deg. below the +freezing point, or about 200 deg. below that of their own bodies, and +still they were able to resist this low temperature, and escape being +"frost-bitten." + +551. Captain Lyon, who accompanied Captain Parry in his second voyage +to the northern regions, found the temperature of an arctic fox to be +106 deg., while that of the atmosphere was 32 deg. below zero; making a +difference between the temperature of the fox and that of the +atmosphere, of 138 deg. Captain Scoresby found the temperature of a +whale, in the Arctic Ocean, to be 104 deg., or nearly as high as that of +other animals of the same kind in the region of the equator, while the +temperature of the ice was as low as 32 deg., and the water was nearly as +cold. These facts show what a strong counteracting energy there is in +animals against the effects of cold. + +552. On the other hand, it has been ascertained by numerous and +well-conducted experiments, that the human body can be exposed, even +for a length of time, to a very high temperature, without essentially +elevating that of the body. Chantrey, the sculptor, often entered the +furnace, heated for drying his moulds, when the temperature indicated +by the thermometer was 330 deg. Chaubert, the Fire-King, is said to have +entered ovens when heated to 600 deg. In 1774, Sir Charles Blagden +entered a room in which the mercury rose to 260 deg. He remained eight +minutes without suffering. + + -=-=-=-=-=-=-=-=-=-=-=-= + +549. What is the temperature of the human body? Of birds? How does the +heat of the atmosphere in summer, in our latitude, compare with that +of the human system? 550. What is related of Captain Parry? Of Captain +Back? 551. Of Captain Lyon? Of Captain Scoresby? What do these facts +show? 552. What has been ascertained on the other hand? + + -=-=-=-=-=-=-=-=-=-=-=-= + +553. In order to render it certain that there was no fallacy, says Sir +Charles Blagden, "in the degree of heat shown by the thermometer, but +that the air breathed was capable of producing all the well-known +effects of such a heat on inanimate matter, I put some eggs and +beefsteak upon a tin frame placed near the thermometer, and farther +distant from the cockle than from the wall of the room. In about +twenty minutes the eggs were taken out, roasted quite hard; and in +forty-seven minutes, the steak was not only dressed, but almost dry." + +554. If a thermometer be placed under the tongue of a healthy person, +in all climates and seasons the temperature will be found nearly the +same. Sir Charles Blagden, "while in the heated room, breathed on a +thermometer, and the mercury sank several degrees; and when he expired +forcibly, the air felt cool as it passed through the nostrils, though +it was scorching hot when it entered them in inspiration." + +_Observation._ Did not the human body possess within itself the power +of generating and removing heat, so as to maintain nearly an equality +of temperature, the most fatal consequences would ensue. In northern +latitudes, especially, in severe weather of winter, the blood would be +converted into a solid mass, and on the other hand, the fatty +secretion, when subjected to equatorial heat, would become fluid, and +life would be extinguished. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is related of Chantrey? Of Chaubert? Of Sir Charles Blagden? 553. +Give Sir Charles's own statement. 554. What is said of the temperature +of the human tongue? Mention the experiment by Sir Charles Blagden. +What would be the effect if the human system did not maintain an +equality of temperature? + + -=-=-=-=-=-=-=-=-=-=-=-= + +555. To enable man, and other warm-blooded animals, to maintain this +equilibrium of temperature under such extremes of heat and cold, +naturally suggests two inquiries: 1st. By what organs is animal heat +generated? 2d. By what means is its uniformity maintained? + +556. The ancients had no well-arranged theory on the subject of animal +heat. They believed that the chief object of respiration was to cool +the blood, and that the heart was the great furnace where all the heat +was generated. At a later period, Mayow, from his discoveries +respecting respiration, asserted that the object of respiration was to +produce heat, and denied that the blood was cooled in the lungs. + +557. When it was discovered that, both in combustion and respiration, +carbonic acid was produced and oxygen absorbed, it led Dr. Black to +conclude that breathing was a kind of combustion by which all the heat +of the body was produced. This theory was objected to, because, if all +the heat was generated in the lungs, like those parts of a stove in +contact with the fuel, they would be at a higher temperature than +those parts at a distance, which was known not to exist. + +558. The next theory, and one which received the sanction of the +scientific men of Europe, was proposed by Dr. Crawford. He agreed with +Dr. Black that heat not only was generated in the lungs, but that the +arterial blood had a greater capacity for heat than the venous, and +that this increase of capacity takes place in the lungs. At the moment +heat is generated, a portion of it, under the name of latent heat, is +absorbed and conveyed to the different parts of the body Wherever +arterial blood is converted into venous, this latent heat is given +out. But, unfortunately for this theory, Dr. Davy proved the capacity +of both, for heat, to be nearly the same. + + -=-=-=-=-=-=-=-=-=-=-=-= + +555. What inquiries are naturally suggested? 556. What was the theory +of the ancients? What did Mayow assert at a later period? 557. What +was the theory of Dr. Black? The objection? 558. What was the theory +of Dr Crawford? + + -=-=-=-=-=-=-=-=-=-=-=-= + +559. No one can doubt that respiration and animal heat are closely +connected. Those animals whose respiratory apparatus is the most +extended, have the highest temperature. An example is seen in birds, +whose organs of respiration extend over a large part of the body, and +their temperature is 12 deg. above man; while the respiratory apparatus of +cold-blooded animals, as some kinds of fish, is imperfect, and only a +small quantity of blood is subjected, at any time, to the effects of +respiration. + +560. To understand the process by which heat is generated in the human +system and in animals, it will be necessary to state: 1st. That the +apparent heat of a body, as perceived by the touch, or as indicated by +a thermometer, is not the measurement of heat contained in the body, +or its capacity for heat. + +_Illustration._ If we mix one pound of water, at the temperature of +60 deg., with another pound at 91 deg., the resulting temperature will be +exactly the medium, or 75 1/2 deg. But, if we mix a pound of water at 60 +deg. with a pound of quicksilver at 91 deg., the resulting temperature +will be only 61 deg., because the capacity of water for heat is so much +greater than that of quicksilver, that the heat which raised the +quicksilver 31 deg. will raise the water only 1 deg. + +561. 2d. When the density and the arrangement of the atoms of a body +are changed, its capacity to hold heat in a latent state is altered. +If it will retain more, heat will be absorbed from contiguous and +surrounding substances; but, if its capacity for caloric is lessened, +heat will be set free and given out to surrounding bodies. + + -=-=-=-=-=-=-=-=-=-=-=-= + +The objection? 559. In what do all the physiologists of the present +day concur? How is it proved that respiration and animal heat are +closely connected? 560. What is said of the apparent heat of bodies? +How is this illustrated? 561. What is the effect when the density and +the arrangement of the atoms of a body are changed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustrations._ 1st. Ice and salt, (Chl. of Sodium,) when mixed, are +converted into a fluid. In this state they will hold more heat than +when solid. The heat necessary to produce this change is drawn from +the surrounding medium, which is made proportionally colder by the +loss of caloric imparted to the ice and salt. It is by this chemical +process that "ice-cream" is made. + +2d. On the other hand, mix water and sulphuric acid, (oil of vitriol,) +of the temperature of 60 deg., and the mixture will become quite warm, +and will freely impart its heat to surrounding and contiguous objects. + +562. The same principle is exhibited, when oxygen unites with an +inflammable body, as in the burning of wood, coal, oil, &c. In +combustion, the oxygen of the atmosphere unites with carbon and +hydrogen, and carbonic acid and water are produced. This process, +according to all the known laws of caloric, is attended with heat. The +quantity of heat disengaged in combustion is always in proportion to +the amount of carbon and hydrogen consumed; thus a piece of wood +weighing one pound, in burning slowly, would give out the same +quantity of heat as a pound of shavings of the same wood, in burning +rapidly. Upon these principles, the production of animal heat may be +understood. + +563. The food contains carbon and hydrogen. These exist in the chyle. +The old and waste atoms of the body likewise contain the same +elements. In the lungs the oxygen and nitrogen of the inspired air are +separated. It is now supposed that the oxygen enters the capillary +vessels of the lungs, and mingles with the blood, with which it is +carried to the heart and thence to the nutrient capillary vessels of +every part of the system. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give the 1st illustration. The 2d. 562. What changes take place when +oxygen unites with an inflammable body? To what is the quantity of +heat proportionate in combustion? Give an example. 563. How are carbon +and hydrogen supplied to the system? How the oxygen? Where does the +oxygen mingle with the blood? + + -=-=-=-=-=-=-=-=-=-=-=-= + +564. In the capillary vessels, the oxygen of the arterial blood unites +with the carbon and hydrogen which the refuse materials contain, and +carbonic acid and water are formed. The combustion of carbon and +hydrogen in the capillaries of every part of the system, (the lungs +not excepted,) is attended with a disengagement of heat, and the +carbonic acid and water are returned to the lungs in the dark-colored +blood, and evolved from the system. + +565. Sir Benjamin Brodie and some others have maintained, that the +heat of the system is generated exclusively by the influence of the +brain and nerves. This theory is discarded by most physiologists; yet +it is true that the nervous system exercises a great influence over +the action of the capillary vessels in the process of nutrition, +secretion, and absorption. When these operations are most active, the +change among the particles of matter of which the body is composed, is +then greatest, and the generation of heat is increased in a +corresponding degree. + +566. The necessity of pure, red blood in the production of animal +heat, is shown when the vessels that carry blood to a limb are +ligated, or tied; the part immediately becomes colder. The necessity +of nervous influence is seen in the diminished temperature of a +paralytic limb. + +567. Our next inquiry is, By what means is the uniformity of +temperature in the body maintained? As there is a constant generation +of heat in the system, there would be an undue accumulation,--so much +so as to cause disagreeable sensations,--if there were no means by +which it could be evolved from the body, or its production lessened. + + -=-=-=-=-=-=-=-=-=-=-=-= + +564. Where does it unite with the carbon and hydrogen contained in the +body, and how is heat generated? 565. What was the theory of Sir +Benjamin Brodie? Is this theory in general discarded? What is true of +this theory? 566. How is the necessity of pure, red blood and nervous +action shown in the production of animal heat? + + -=-=-=-=-=-=-=-=-=-=-=-= + +568. It has been ascertained that the principal means by which the +system is kept at a uniform temperature, is the immense evaporation +from the skin and lungs. These membranes, in an ordinary state, are +constantly giving out water, which is converted into vapor, and +carried off by the surrounding air. The quantity of heat abstracted +from the system to effect this, depends on the rapidity of the change +of air, its temperature, and the amount of water it contains in a +state of vapor. The quantity removed is greatest when the air is warm +and dry, and the change, or current, rapid. + +_Observations._ 1st. The first discovery of the use of free +evaporation of the perspiration from the skin in reducing the heat of +the body, and the analogy subsisting between this process and that of +the evaporation of water from a rough porous surface, so constantly +resorted to in warm countries, as an efficacious means of reducing the +temperature of the air in rooms, and of wine and other drinks, much +below that of the surrounding atmosphere, was made by Franklin. + +2d. In all ages and climes, it has been observed that the increased +temperature of the skin and system in fevers, is abated as soon as +free perspiration is restored. In damp, close weather, as during the +sultry days of August, although the temperature is lower, we feel a +disagreeable sensation of heat, because the saturation of the air with +moisture lessens evaporation, and thus prevents the escape of heat +through the lungs and skin. + +3d. It is on the principle of the evaporation of fluids that warm +vinegar and water, applied to the burning, aching head, cools it, and +imparts to it a comfortable feeling. The same results follow if warm +liquids are applied to the skin in the hot stage of fever; and this +evaporation can be increased by constant fanning. + + -=-=-=-=-=-=-=-=-=-=-=-= + +568. What are the principal means by which a uniform temperature of +the body is maintained? On what does the quantity of heat abstracted +from the system depend? What discovery relative to animal heat is due +to Franklin? What is said of free perspiration in fevers? What +occasions the disagreeable sensation of heat in damp, close weather? + + -=-=-=-=-=-=-=-=-=-=-=-= + +4th. It is frequently noticed, in very warm weather, that dogs and +other domestic animals are seen with their tongues out of their +mouths, and covered with frothy secretions. This is merely another +mode of reducing animal heat, as the skin of such animals does not +perspire as much as that of man. + +569. Under some circumstances, a portion of the heat of the system is +removed by radiation. When cold air comes in contact with the skin and +mucous membrane of the lungs, heat is removed from the body, as from a +stove, to restore an equilibrium of temperature. The removal of heat +from the body is greatest when we are in a current of cold air, or +when a brisk, cold wind is blowing upon us. + +570. As the primary object of the different processes of nutrition is +to supply animal heat, so the action of the different nutritive organs +is modified by the demands of the system for heat. When heat is +rapidly removed from the body, the functional activity of the organs +of nutrition is increased. When the system is warmed by foreign +influence, the activity of the nutritive organs is diminished. This +leads to the natural, and, we may add, instinctive change in the +quality and quantity of food at different seasons of the year. + + -=-=-=-=-=-=-=-=-=-=-=-= + +569. When is heat radiated from the body? When is it greatest? 570. +What is the primary object of the different processes of nutrition? +When is the activity of the nutritive organs increased? When +diminished? To what does this lead? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXVIII. + +HYGIENE OF ANIMAL HEAT. + + +571. The amount of heat generated in man and inferior animals depends +upon the quantity and quality of the food, age, exercise, the amount +and character of the respired air, condition of the brain, skin, and +general system. + +572. _Animal heat is modified by the proportion of digestible carbon +which the food contains, and by the quantity consumed._ As the kind of +fuel that contains the greatest amount of combustible material evolves +the most caloric when burned, so those articles of food that contain +the greatest quantity of carbon produce the most heat when converted +into blood. The inhabitants of the frigid zones, and individuals in +temperate climates during the cold season, consume with impunity +stimulating animal food, that contains a large proportion of carbon, +while the inhabitants of the tropical regions, and persons in +temperate climates during the warm season, are more healthy with a +less stimulating or vegetable diet. + +_Observation._ When we ride or labor in cold weather, an adequate +amount of nutritious food will sustain the warmth of the system better +than intoxicating drinks. + +573. _Age is another influence that modifies the generation of animal +heat._ The vital forces of the child being feeble, less heat is +generated in its system than in that of an adult. The experiments +of Dr. Milne Edwards show that the power of producing heat in +warm-blooded animals, is at its minimum at birth, and increases +successively to adult age; and that young children part with their +heat more readily than adults, and, instead of being warmer, are +generally a degree or two colder. After adult age, as the vital powers +decline, the generation of heat is diminished, as the energies of +the system are lessened. Hence the young child, and the debilitated +aged person, need more clothing than the vigorous individual of +middle age. + + -=-=-=-=-=-=-=-=-=-=-=-= + +571-585. _Give the hygiene of animal heat._ 571. State some of the +influences that modify the generation of animal heat. 572. What +element of the food influences the generation of heat? When and +where can animal food be eaten with impunity? Give the practical +observation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +574. _Exercise is an influence that modifies the generation of animal +heat._ As carbon and hydrogen enter into the composition of the organs +of the body, whatever increases the flow of blood in the system, +increases also the deposition of new material, and the removal of the +waste particles. This change among the particles of matter is attended +with an elevation of temperature, from the union of oxygen with the +carbon and hydrogen of the waste atoms. For this reason, a person in +action is warmer than in a quiescent state. Consequently, the amount +of clothing should be increased, when exercise or labor is diminished +or suspended. + +575. On the other hand, whatever impedes the circulation and the +interchange of the atoms of matter, diminishes animal heat. Common +observation shows, that the extremities are not as warm when tight +gloves or boots are worn as when they are loose. One reason is, the +circulation of blood is impeded, which is attended with less frequent +change of the particles of matter. + +576. _The quantity of air which is inhaled modifies the heat of the +system._ In the generation of heat in a stove, air, or oxygen, is as +essential as the wood or coal. It is equally so in the production of +animal heat. The oxygen of the inspired air should be in proportion to +the carbon and hydrogen to be consumed. This requires voluminous +lungs, together with free movements of the ribs and diaphragm. A +person whose chest is small, and whose apparel is worn tight over the +ribs, suffers more from the cold, and complains more frequently of +chilliness and cold extremities, than the broad-chested and loosely +dressed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What do the experiments of Dr. Milne Edwards show? 574. Why does +exercise influence animal heat? 575. What is the effect when the +circulation of blood is impeded? Give examples. 576. Why do those +persons that have broad chests and voluminous lungs suffer less from +cold than the narrow-chested with small lungs? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Fishes that breathe by means of gills, as the cod, +pike, &c., depend solely on the small quantity of oxygen that is +contained in the air mixed with the water. Their temperature is not +much greater than the medium in which they live. Whales, dolphins, +&c., breathe by means of lungs, and the inhalation of atmospheric air +makes their temperature about 100 deg., independent of the heat of the +element in which they live. + +577. _The quality of respired air influences the generation of animal +heat._ In vestries, and other public rooms, when crowded with an +audience, where the ventilation is inadequate, the lamps will emit but +a faint light, because the oxygen is soon expended, and there is not +enough of the vivifying principle to unite with the oil and disengage +light. In the human body, when the respired air has lost some of its +life-giving properties, the combustion that takes place in different +parts of the system is not so complete as when it contains a proper +proportion of oxygen; and hence less heat is disengaged. For this +reason, those persons that breathe impure air, either in the daytime +or night, require more clothing, than those that work and sleep in +well-ventilated rooms. + +578. _The condition of the brain and nervous system affects the +generation of animal heat._ If the brain is diseased, or the mind is +absorbed in thought, depressed by sorrow, or aroused from fear, the +breathing becomes slow and scarcely perceptible, and a chilliness +pervades the body, particularly the extremities; while, on the +contrary, if the mind and nervous system are excited by joyous and +agreeable emotions, the circulation of blood is quicker, and the +system more powerfully resists external cold. During sleep, when the +brain is partially inactive, less heat is generated than when awake. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is said of those fishes that breathe by means of gills? Of those +that breathe by means of lungs? 577. Why do lamps give but a faint +light in crowded, unventilated rooms? What effect on animal heat has +impure air? 578. Mention the effects of some of the mental emotions on +animal heat. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ The preceding remark explains why an individual who +sleeps in the same clothing that was adequate to prevent chills while +awake, contracts a cold, unless he throws over him an additional +covering. + +579. _The state of the skin exercises much influence in the generation +of heat._ If the functions of this membrane are not interrupted, more +heat will be generated than when it is pallid and inactive. The action +of the capillaries is most energetic when the skin is clean; on this +account, before taking a walk or a ride, in cold weather, remove all +impurities from the skin, by thorough ablution and vigorous friction. + +580. _The amount and kind of clothing modify the temperature of the +system._ Those persons that are well clothed have greater power to +resist cold than the thinly apparelled, because both the evaporation +and the radiation from the skin are impeded, and less heat, in +consequence, is abstracted from the body. If the articles of apparel +possess the property of retaining air in their meshes, as flannel, the +removal of heat is not as rapid as when linen is worn. + +_Observation._ In winter, although more heat is generated in the +system than in summer, yet we require more clothing, and also those +articles that are poor conductors of heat, because caloric is more +rapidly extracted in clear, cold weather, than in a warm day. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does the preceding remark explain? 579. What suggestion +respecting the condition of the skin before taking a walk or ride in a +cold day? Why? 580. Do the amount and kind of clothing affect animal +heat? What is said of well-clothed persons? When does the system +generate the most heat? + + -=-=-=-=-=-=-=-=-=-=-=-= + +581. _The health and constitution influence the generation of heat._ +When the health is firm, and the constitution vigorous, less clothing +is needed, for the change among the particles of matter is more rapid, +and more heat is generated, than when the opposite condition obtains. +Persons of a feeble constitution, particularly, if any of the vital +organs[18] are diseased, need more clothing and require rooms of a +warmer temperature, than individuals who are free from disease and +have a vigorous constitution. + + [18] The brain, lungs, heart, and digestive organs, are called _vital_ + organs. + +_Observation._ Persons who are infirm, and whose vital powers are +feeble, in general, accustom themselves to an undue amount of clothing +and warm rooms. A more judicious practice would be, to exercise more +and use a moderate amount of clothing, together with a more nutritious +diet. + +582. _The surplus heat should be removed equally from all parts of the +system._ The rapid evaporation of fluids, as in free perspiration, or +from radiation, as in a cold atmosphere, is attended with a removal of +heat from the system. This modifies the action of the circulatory +vessels. Consequently, if heat is suddenly and rapidly abstracted from +one part of the system, the equilibrium of the circulation is +destroyed, which will produce disease. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Why do we, then, require more clothing in winter than in summer? 581. +Why do persons of firm health and vigorous constitutions need less +clothing than those who are feeble? What is a general practice among +infirm persons? What would be more judicious? 582. Why should the +surplus heat be removed equally from all parts of the system? What is +said respecting currents of air from small apertures? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Currents of air that impinge upon small portions of the +body, as from small apertures, or from a window slightly raised, +should be avoided. They are more dangerous than to expose the whole +person to a brisk wind, because the current of air removes the heat +from the part exposed, which disturbs the circulation of blood and +causes disease, usually in the form of "colds." For the same reason, +it is not judicious to stand in an open door, or the opening of a +street. + +583. _The system suffers less when the change of temperature is +gradual._ The change in the production of heat, as well as in the +evaporation of fluids from the system, is gradual when not influenced +by foreign causes. This gradual change is known under the name +_acclimation_. By this means the body is enabled to endure tropical +heat and polar cold. Owing to this gradual adaptation of the system to +different temperatures, we can bear a greater degree of heat in the +summer between the tropics, than in the winter under the polar +circles. On the other hand, we can endure a greater degree of cold in +winter and in the arctic region, than in the summer and in equatorial +countries. + +584. The sensation of heat which would be oppressive in a mild, warm +day of January, would only be grateful in July, and a degree of cold +which could scarcely be endured in August, would not be uncomfortable +in December. The changes of season in our latitude prevent the +disagreeable and perhaps fatal consequence that would follow, if no +spring or autumn intervened between the severity of winter's cold and +the intensity of summer's heat. During the transition periods, the +constitution is gradually changed, and adapted to bear the extremes of +temperature without suffering. The amount of heat generated in the +nutrient capillary vessels, is likewise diminished or increased as the +temperature of the season becomes greater or less. + + -=-=-=-=-=-=-=-=-=-=-=-= + +583. In what manner should change of temperature take place, to be +adapted to the body? How is the body enabled to endure tropical heat +and polar cold? State some of the effects of the gradual adaptation of +the system to different temperatures. 584. What is said relative to a +warm day in winter? To a cold day in summer? What is said of the +changes of seasons in our latitude? What effect on the constitution +during spring and autumn? What change in the amount of heat +generated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +585. But, on the contrary, we cannot suddenly pass from one extreme of +temperature to the other with impunity. Let an inhabitant of Quebec +suddenly arrive in Cuba in February, and he would suffer from languor +and exhaustion; after becoming acclimated to this tropical climate, +let him suddenly return to Quebec in January, and the severity of the +weather would be almost insupportable. + +_Observations._ 1st. Experience shows that heated rooms, as well as +tropical climates, lessen the generation of heat in the body, and +likewise the power of resisting cold. It would be idle for the +merchant from his warehouse, or the mechanic from his heated shop, to +attempt to sit on the box with a coachman, with the same amount of +clothing as his companion, who is daily exposed to the inclemency of +the weather. + +2d. "It is the power of endurance of cold at one period, and the +absence of its necessity at another, that enables animals, in +their wild and unprotected state, to bear the vicissitudes of the +seasons with so little preparation in clothing, and so little real +inconvenience." + + -=-=-=-=-=-=-=-=-=-=-=-= + +585. What effect on the system has a sudden transition from a cold to +a warm climate? What does experience show? Why do wild animals bear +the vicissitudes of the seasons with so little preparation in +clothing? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXIX. + +THE VOICE. + + +586. The beautiful mechanism of the vocal instrument, which produces +every variety of sound, from a harsh, unmelodious tone, to a soft, +sweet, flute-like sound, has, as yet, been imperfectly imitated by +art. It has been compared, by many physiologists, to a wind, reed, and +stringed instrument. This inimitable, yet simple instrument, is the +_Lar'ynx_. + +587. Incidentally, the different parts of the respiratory organs, as +well as the larynx, are subservient to speaking and singing. The +tongue, nasal passages, muscles of the fauces and face, are agents +which aid in the intonation of the voice. + + +ANATOMY OF THE VOCAL ORGANS. + +588. The LARYNX is a kind of cartilaginous tube, which, taken as a +whole, has the general form of a hollow, reversed cone, with its base +upward toward the tongue, in the shape of an expanded triangle. It +opens into the pharynx, at its superior extremity, and communicates, +by its inferior opening with the trachea. It is formed by the union of +five cartilages, namely, the _Thy'roid_, the _Cri'coid_, the two +_A-ryt-e'noid_, and the _Ep-i-glot'tis_. These are bound together by +ligaments, and moved by muscles. + + -=-=-=-=-=-=-=-=-=-=-=-= + +586. What is said of the structure of the vocal instrument? With what +instrument have physiologists compared it? What is the vocal +instrument called? 587. What organs are called into action in speaking +beside the larynx? 588-596. _Give the anatomy of the vocal organs._ +588. Describe the larynx. Name the cartilages that form the larynx. + + -=-=-=-=-=-=-=-=-=-=-=-= + +589. The THYROID CARTILAGE is the largest of the five, and forms the +prominence in the front of the neck, called _Po'mum A-da'mi_, (Adam's +apple.) It is composed of two parts, and is connected with the bone of +the tongue above, and with the cricoid cartilage below. + +590. The CRICOID CARTILAGE takes its name from its resemblance to a +ring. It is situated below the thyroid cartilage, it is narrow in +front, broader at the sides, and still broader behind, where it is +connected with the thyroid cartilage. Below, it connects with the +first ring of the trachea. + +[Illustration: Fig. 102. A side view of the cartilages of the larynx. * +The front side of the thyroid cartilage. 1, The os hyoides, (bone at the +base of the tongue.) 2, The ligament that connects the hyoid bone and +thyroid cartilage. 3, 4, 5, The thyroid cartilage. 6, The cricoid +cartilage. 7, The trachea.] + +[Illustration: Fig. 103. A posterior view of the cartilages and ligaments +of the larynx. 1, The posterior face of the epiglottis. 3, 3, The os +hyoides. 4, 4, The lateral ligaments which connect the os hyoides and +thyroid cartilage. 5, 5, The posterior face of the thyroid cartilage. 6, +6, The arytenoid cartilages. 7, The cricoid cartilage. 8, 8, The junction +of the cricoid and the arytenoid cartilages. 12, The first ring of the +trachea.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +589. Describe the thyroid cartilage. 590. From what does the cricoid +cartilage derive its name? Where is it situated? Explain fig. 102. +Fig. 103. + + -=-=-=-=-=-=-=-=-=-=-=-= + +591. The ARYTENOID CARTILAGES are small triangular bodies placed upon +the back part of the cricoid cartilage. They are connected with the +thyroid cartilages, by four ligaments, called _Vo'cal Cords_. + +592. The EPIGLOTTIS is fibro-cartilaginous, and is placed behind the +base of the tongue. In shape it resembles a leaf of parsley. + +593. The VOCAL CORDS, or ligaments, are formed of elastic and parallel +fibres, enclosed in a fold of mucous membrane. They are about two +lines in width, and pass from the anterior angle of the thyroid +cartilage, to the two arytenoid cartilages. The one is called the +superior, and the other the inferior vocal ligament. The cavity, or +depression between the superior and inferior ligament, is called the +_ventricle_ of the larynx. The aperture, or opening between these +ligaments, is called the _glot'tis_, or _chink of the glottis_. It is +about three fourths of an inch in length, and one fourth of an inch in +width, the opening being widest at the posterior part. This opening is +enlarged and contracted by the agency of the muscles appropriated to +the larynx. + +[Illustration: Fig. 104. An ideal, lateral section of the larynx. 1, 1, +The upper vocal cords. 2, 2, The lower vocal cords. 3, 3, The glottis. 4, +4, The ventricles of the larynx.] + +[Illustration: Fig. 105. A vertical section of the larynx. 2, The os +hyoides. 4, The apex of the epiglottis. 7, The superior vocal ligament. +9, The ventricle of the larynx. 10. The lower vocal ligament. 11, The +arytenoid cartilage. 12, 13, The cricoid cartilage. 14, The trachea. 18, +The oesophagus.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +591. Describe the arytenoid cartilages. 592. What is said of the +epiglottis? 593. Give the structure of the vocal cords. Where is the +ventricle of the larynx? Where is the glottis situated? What is +represented by fig. 104? Explain fig. 105. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 106. A view of the larynx from above, showing the +vocal ligaments. 1, The anterior edge of the larynx. 4, The posterior +face of the thyroid cartilage. 5, 5, The arytenoid cartilages. 6, 6, The +vocal ligaments. 7, Their origin, within the angle of the thyroid +cartilage. 9, Their termination, at the base of the arytenoid cartilages. +8, 10, The glottis.] + +594. The larynx is connected by muscles with the sternum, oesophagus, +base of the skull, hyoid bone, lower jaw, and tongue. This organ is +supplied with a large number of blood-vessels, and it likewise +receives nerves from the sympathetic system, and two large nerves from +the tenth pair. The number and size of the nervous filaments +distributed to the mucous membrane of the larynx, render it more +sensitive than any other portion of the respiratory organs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is the glottis enlarged or contracted? Explain fig. 106. 594. By +what means and to what organs is the larynx connected? Why is the +larynx more sensitive than other parts of the respiratory organs? + + -=-=-=-=-=-=-=-=-=-=-=-= + +595. The larynx is much more developed and prominent in man than in +woman. In the former, the anterior angle of the thyroid cartilage is +acute, while in the latter it is rounded, and the central slope of the +superior border of the same cartilage is less deep, and the epiglottis +smaller and less prominent, than in man. + +596. The difference in the formation of the larynx in infancy is less +striking; but at a later period, it is more developed in the male than +in the female. It is very remarkable that this increase is not +progressive, like that of other organs, but, on the contrary, develops +itself at once at the period of puberty. + + +PHYSIOLOGY OF THE VOCAL ORGANS. + +597. In the formation of the voice, each part already described +performs an important office. The cricoid and thyroid cartilages give +form and stability to the larynx; the arytenoid cartilages, by their +movement, vary the width of the glottis. The epiglottis is flexible +and elastic. When it is erect, the chink of the glottis is open, as in +inspiration; when depressed, as in swallowing food and drink, it +covers and closes this aperture. It prevents the introduction of +articles of food into the trachea, and probably modifies sound as it +issues from the glottis. + +598. The muscles of the neck elevate and depress the larynx; the +muscles of the larynx increase or diminish the width of the glottis; +at the same time, the vocal cords are relaxed or tightened, while the +muscles of the face open and close the mouth. + + -=-=-=-=-=-=-=-=-=-=-=-= + +595. What difference between the formation of the larynx of the female +and that of the male? 596. Does this difference exist in childhood? Is +its development progressive? 597-600. _Give the physiology of the +vocal organs._ 597. Which cartilages give stability and form to the +larynx? Which vary the width of the glottis? What is the function of +the epiglottis? 598. What effect have the muscles of the neck upon the +larynx? The use of the muscles of the larynx? + + -=-=-=-=-=-=-=-=-=-=-=-= + +599. The elasticity of the ribs and the contraction of the abdominal +muscles diminish the cavity of the chest, and the air, in consequence, +is pressed from the air-cells into the bronchial tubes and trachea. It +then rushes by the vocal cords, and causes a peculiar vibration, which +produces _sound_. + +_Observations._ 1st. Experiments have satisfactorily shown that the +vocal cords are the principal agents in the formation of the voice. +The tongue, which many have supposed to be the most important organ in +speaking, is not essential to sound. In several instances it has been +removed, and the persons thus mutilated could speak with fluency. + +2d. When the vocal cords are ulcerated, or inflamed, however slightly, +as in sore throat produced by a cold, the voice will be changed. The +loss of speech among public speakers is generally produced by a +relaxation of the vocal ligaments. Hence, bronchitis is a misnomer for +this affection. + +600. Sound is varied by the velocity of the expelled current of air, +and the tension of the vocal ligaments. The size of the larynx, the +volume and health of the lungs, the condition of the fauces and nasal +passages, the elevation and depression of the chin, the development +and freedom of action of the muscles which are attached to the larynx, +the opening of the mouth, the state of the mind, and general health of +the system, influence the modulations of sound. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What effect has the combined action of these muscles? 599. How is +sound produced? What have experiments shown? What effect has disease +of the vocal ligaments upon the voice? 600. How is sound varied? +Mention other conditions that contribute to the modulation of sound. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXX. + +HYGIENE OF THE VOCAL ORGANS. + + +601. _The voice can be changed and modified by habit._ Sailors, +smiths, and others, who are engaged in noisy occupations, exert their +vocal organs more strongly than those of more quiet pursuits. This not +only affects the structure of the vocal organs, but varies the +intonation of the voice. + +602. _The voice is strong in proportion to the development of the +larynx, and the capacity of the chest._ Singing and reading aloud +improve and strengthen the vocal organs, and give a healthy expansion +to the chest. The enunciation of the elementary sounds of the English +language, aids in developing the vocal organs, as well as preventing +disease of the throat and lungs. This exercise also conduces to the +acquisition of musical sounds. + +603. _The attitude affects the modulation of the voice._ When an +individual stands erect, the movements of the whole respiratory +apparatus are most free and effective. The larynx is brought forward +by the erect position of the head and the elevation of the chin. The +muscles of the arytenoid cartilages are then brought to a proper +relation for action, by which a tension of the vocal cords is +produced, that favors clear and harmonious enunciation. + +_Experiment._ Read with the head bowed forward and the chin depressed; +then read with the head erect and the chin elevated, and the +difference in the movement of the vocal organs, together with the +difference in the voice, will be manifest. + + -=-=-=-=-=-=-=-=-=-=-=-= + +601-616. _Give the hygiene of the vocal organs._ 602. How may the +voice be strengthened? 603. What effect has the erect attitude upon +the modulations of the voice? Give the experiment. + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 107. An improper position; but one not unfrequently +seen in some of our common schools, and in some of our public speakers.] + +[Illustration: Fig. 108. The proper position for reading, speaking, and +singing.] + +604. If an individual or class read or sing when sitting, let the +position represented by fig. 109 be adopted, and not the one +represented by fig. 110; for the erect position in sitting conduces to +the free and effective action of the respiratory and vocal organs, and +is as important as the erect attitude in standing. + + -=-=-=-=-=-=-=-=-=-=-=-= + +604. What position should be adopted when a person reads or sings when +sitting? Why? + + -=-=-=-=-=-=-=-=-=-=-=-= + +605. _The muscles of the neck should not be compressed._ If the +muscles of the neck and larynx are compressed by a high cravat, or +other close dressing, not only will the free and energetic movements +of these parts be impeded, but the tones will be feeble and +ineffective. Therefore the dress of the neck, particularly of public +speakers and singers, should be loose and thin. For a warm dress upon +the neck, when the vocal organs are in action, will induce too great a +flow of blood to these parts, which will be attended by subsequent +debility. + +[Illustration: Fig. 109.] + +_Observations._ 1st. The loss of voice, (_lar-yn-gi'tis_,) which is +prevalent among public speakers, may be ascribed in part to the +injudicious dressing of the neck, and improper position in standing. + + -=-=-=-=-=-=-=-=-=-=-=-= + +605. How should public speakers dress their necks? Why? What is a +common cause of the loss of voice? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. When individuals have been addressing an audience in a warm room, +or engaged in singing, they should avoid all impressions of a cold +atmosphere, unless adequately protected by an extra garment. + +[Illustration: Fig. 110.] + +606. _The condition of the air modifies speaking and singing._ As pure +air is more elastic and resonant than impure, and as easy, melodious +speaking or singing requires atmospheric elasticity, so school-rooms +and singing-halls should be well ventilated, if we would be +entertained with soft intonations in reading, or sonorous singing. + +_Observation._ The imperfect ventilation of churches and vestries is +another cause of laryngitis among clergymen. This affection is almost +unknown among those who speak in very open rooms, where stoves are not +used. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give 2d. observation. 606. Why does easy and melodious speaking +require pure air? What is another cause laryngitis among clergymen? + + -=-=-=-=-=-=-=-=-=-=-=-= + +607. _The condition of the nasal passages and throat modifies the +voice._ The enunciation of words is rendered more or less distinct, in +proportion as the jaws are separated in speaking, and the fauces and +nasal passages are free from obstruction. For these reasons, the +scholar should be taught to open the mouth adequately when reading, +speaking, or singing, that the sounds formed in the larynx and +modified in the fauces may have an unobstructed egress. + +_Observations._ 1st. If the fauces are obstructed by enlarged tonsils, +(a condition by no means uncommon in children,) they should be removed +by a surgical operation, which is not only effective, but safe, and +attended with little suffering. The tonsils are situated on each side +of the base of the tongue, and, when enlarged, they obstruct the +passage through which the air passes to and from the lungs, and the +respiration is not only laborious, but distressing. + +2d. When the nasal passages are obstructed, there is a peculiar sound +of the voice, which is called "talking through the nose." This +phenomenon arises, not from the expired air passing through the nose, +but from its not being able to pass through the nasal passages. + +608. _The state of the mind and health exerts an influence upon the +vocal organs._ "The organs of the voice, in common with all other +parts of the bodily frame, require the vigor and pliancy of muscle, +and the elasticity and animation of mind, which result from good +health, in order to perform their appropriate functions with energy +and effect. But these indispensable conditions to the exercise of +vocal organs, are, in the case of most learners, very imperfectly +supplied." + + -=-=-=-=-=-=-=-=-=-=-=-= + +607. Does the condition of the throat and nasal passages modify the +voice? Name the influences that produce clear enunciation of words. +What is the effect when the nasal passages are obstructed? 608. How +are the vocal organs influenced? What do they require? + + -=-=-=-=-=-=-=-=-=-=-=-= + +609. "A sedentary mode of life, the want of invigorating exercise, +close and long-continued application of mind, and, perhaps, an +impaired state of health, or a feeble constitution, prevent, in many +instances, the free and forcible use of those muscles on which voice +is dependent. Hence arises the necessity of students of elocution +practising physical exercises adapted to promote general muscular +vigor, as a means of attaining energy in speaking; the power of any +class of muscles being dependent on the vigor of the whole system." + +610. "Gymnastic and calisthenic exercises are invaluable aids to the +culture and development of the voice, and should be sedulously +practised when opportunity renders them accessible. But even a slight +degree of physical exercise, in any form adapted to the expansion of +the chest and to the freedom and force of the circulation, will serve +to impart energy and glow to the muscular apparatus of voice, and +clearness to its sound." + +611. "There is, therefore, a great advantage in always practising some +preliminary muscular actions, as an immediate preparation for vocal +exercises. The art of cultivating the voice, however, has, in addition +to the various forms of corporeal exercise, practised for the general +purpose of promoting health, its own specific prescription for +securing the vigor of the vocal organs, and modes of exercise adapted +to the training of each class of organs separately." + +612. The results of such practice are of indefinite extent. They are +limited only by the energy and perseverance of the student, excepting +perhaps in some instances of imperfect organization. A few weeks of +diligent cultivation are usually sufficient to produce such an effect +on the vocal organs, that persons who commence practice with a feeble +and ineffective utterance, attain, in that short period, the full +command of clear, forcible, and varied tone. + + -=-=-=-=-=-=-=-=-=-=-=-= + +609. Why are students of elocution in general necessitated to practise +physical exercise? 610. What are invaluable aids in the culture of the +voice? 611. What is said of the art of cultivating the voice? 612. Are +the results of such practices limited? What exception? + + -=-=-=-=-=-=-=-=-=-=-=-= + +613. _Repetition is essential to distinct articulation of words._ In +teaching a child to articulate a letter or word, in the first +instance, make an effort to induce a proper state of the vocal organs +by which the particular sound is produced. Repeat the letter or word +again and again, until all the parts of the vocal apparatus harmonize +in their movements to produce the given sound. This repetition is as +necessary in learning to read as in singing. + +_Observations._ 1st. There is nothing gained by trying to teach a +child to pronounce the letters of the alphabet, before the vocal +organs are so developed that distinct utterance can be given to the +proper sounds. + +2d. The drawling method of talking to young children, as well as using +words that are not found in any written language, (called child's +talk,) is decidedly wrong. A child will pronounce and understand the +application of a correct word as quickly as an incorrect one. + +614. _No part of the vocal organs is wanting, with those individuals +that stammer, or who have an impediment in their speech._ Some parts +may be more developed than others, but they generally are but +imperfectly under the control of the will, and assume an irregular and +rapid movement, while other parts, the motions of which are essential, +remain comparatively inactive. This can be seen by comparing the +movements of the lips, tongue, and larynx, while attempting to speak, +in a person who stammers, with the movements of the corresponding +parts, while speaking, in an individual who has no such impediment. + + -=-=-=-=-=-=-=-=-=-=-=-= + +613. Is repetition essential to distinct articulation? What method is +suggested in teaching a child to articulate letters or words? Give +observation 1st. Observation 2d. 614. Are the vocal organs wanting in +stammerers? Why the defect in their articulation of words? + + -=-=-=-=-=-=-=-=-=-=-=-= + +615. Surgical operations and medical treatment are not highly +advantageous in a majority of these cases. In the young and middle +aged, this defect can be remedied by _patient_ and judicious training. +At first, only those letters and words should be spoken that can be +articulated with distinctness. Let there be repetition, until the +words can be spoken at any time with readiness. Then take for a lesson +other words, more difficult to articulate; and pursue a similar +process of training and repetition, until every part of the vocal +organs can be called into a ready and harmonious action in giving +utterance to any word in common use. + +616. _The method of removing foreign bodies from the throat._ It is +not necessary to ascertain which passage the foreign body is in, for +the immediate treatment ought in either case to be the same. Some +person should place one hand on the front of the chest of the +sufferer, and, with the other, give two or three smart blows upon the +back, allowing a few seconds to intervene between them. This treatment +will generally be successful, and cause the substance to be violently +thrown from the throat. + +_Observation._ If the foreign body passes into the larynx violent +spasmodic coughing immediately succeeds, which continues until it is +removed or life is extinct. Such cases demand the prompt opening of +the trachea below the larynx by a skilful surgeon. + + -=-=-=-=-=-=-=-=-=-=-=-= + +615. How can stammering be remedied? 616. What is the method of +removing foreign bodies from the throat? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXXI. + +THE SKIN. + + +617. The skin is a membrane which envelops the muscles and other parts +of the system. In youth, and in females particularly, it is smooth, +soft, and elastic. In middle age, and in males, it is firm and rough +to the touch. In old age, in persons who are emaciated, and about the +flexions of the joints, it is thrown into folds. The interior of the +body, like the exterior, is covered by a skin, which, from the +constantly moistened state of its surface, is called the mucous +membrane. At the various orifices of the body, the exterior skin is +continuous with the internal. + + +ANATOMY OF THE SKIN. + +618. The SKIN, to the naked eye, appears composed of one membrane. But +examination has shown that it consists of two layers of membrane, +namely, the _Cu'ti-cle_, (scarf-skin,) and the _Cu'tis Ve'ra_, (true +skin.) These layers are widely different from each other in structure, +and perform very different offices in the animal economy. + +619. The CUTICLE (sometimes called the _ep-i-derm'is_) is the external +layer of the skin. This membrane is thin and semi-transparent, and +resembles a thin shaving of soft, clear horn, and bears the same +relation to other parts of the skin that the rough bark of a tree does +to the liber, or living bark. The cuticle has no perceptible nerves or +blood-vessels; consequently, if it is cut or abraded, no pain will be +felt, and no fluid will ooze from it. + + -=-=-=-=-=-=-=-=-=-=-=-= + +617. What is the skin? Mention its different appearances in its +different conditions in the human frame. Is the interior of the body, +as well as the exterior, covered by a skin? What is the interior +membrane called? Why has it received this name? 618-636. _Give the +anatomy of the skin._ 618. What is said of the skin? What is said +relative to these layers of membrane? 619. Describe the cuticle. What +name is sometimes applied to the cuticle? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Experiment._ Pass a pin through the portion of the cuticle that +skirts the nails, or remove a thin shaving from the palm of the hand, +and no painful sensation will be experienced unless the pin or knife +penetrates deeper than the cuticle. + +620. This membrane varies in thickness on different parts of the +body,--from the thin, delicate skin upon the internal flexions of the +joints, to the thickened covering of the soles of the feet. The +greater thickness of the cuticle of the palms of the hands and soles +of the feet, is manifestly the intentional work of the Creator; for it +is perceptible in infants, even at birth, before exercise can have had +any influence. + +621. The CUTIS VERA (sometimes called the _co'ri-on_) is composed of +minute fibres, which are collected into small bundles or strands. +These are interwoven with each other so as to constitute a firm, +strong, and flexible web. In the superficial part of the true skin, +the web is so close as to have the appearance of felt-cloth; but more +deeply, the pores become progressively larger, and, upon the lower +surface, have a diameter of about a line, or one twelfth of an inch. +This gives the under surface the appearance of a coarse web. The +strands of the under surface of the true skin are connected with the +fibrous web, in which the sub-cutaneous fat of the body is deposited; +while the upper surface gives support to the sensitive, or papillary +layer, which is bedded upon it. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give the experiment. 620. What is said of the thickness of the cuticle +in different parts of the body? 621. Describe the cutis vera. By what +name is it sometimes called? What is the appearance of the upper +surface of the cutis vera? Of the under surface? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ When the skins of animals are immersed in a strong +solution of oak or hemlock bark, a chemical union takes place between +the gelatin, of which the true skin is mostly composed, and the tannin +of the bark. By this process leather is formed, and its peculiar +markings are owing to the papillary layer. + +[Illustration: Fig. 111. An ideal representation of the papillae. 1, 1, +The cutis vera. 2, 2, The papillary layer. 3, 3, The arteries of the +papillae. 4, 4, The veins of the papillae. 5, 5, The nerves of the papillae.] + +622. The sensitive layer of the skin is thin, soft, uneven, pinkish in +hue, and composed of blood-vessels, which confer its various tints of +red; and of nerves, which give it the faculty of sensation. The +unevenness of this layer is produced by small, elongated, conical +prominences, called _Pa-pil'lae_. + +623. Each PAPILLA is composed of a minute artery, vein, and nerve. +Some of the prominences are arranged in concentric ovals, as may be +seen on the ends of the fingers; others are more or less parallel, and +pursue a serpentine course; some suddenly diverge, and again reunite, +as may be seen in the palm of the hand. Papillae are found in every +part of the skin. Consequently, their number is very great. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is leather formed? 622. What is the appearance of the sensitive +layer? What causes the unevenness of this layer? Explain fig. 111. +623. Describe the papillae. + + -=-=-=-=-=-=-=-=-=-=-=-= + +624. The cutis vera contains not only _Arteries_, _Veins_, and +_Nerves_ but _Lymphatics_, _Oil-Glands_ and _Tubes_, and _Perspiratory +Glands_ and _Tubes_. + +[Illustration: Fig. 112. The arteries and veins of a section of the skin. +A, A, Arterial branches. B, B, Capillary, or hair-like vessels, in which +the large branches terminate. C, The venous trunk, collecting the blood +from the capillaries.] + +625. The ARTERIES AND VEINS of the skin are very numerous. The larger +branches of the arteries pass through the open meshes of the true +skin, and are subdivided into a myriad of minute capillary vessels, +which form a beautiful net-work on the upper surface of the true skin. +This vascular net sends a branch to each of the papillae, which opens +into and terminates in a minute vein. The capillary veins are as +numerous as the arteries which they accompany. They unite and form +larger trunks, as small springs from the hill side coalesce to form +rivulets. + + -=-=-=-=-=-=-=-=-=-=-=-= + +624. What vessels are found in the cutis vera? Explain fig. 112. 625. +What is said of the cutaneous arteries? Of the cutaneous veins? + + -=-=-=-=-=-=-=-=-=-=-=-= + +626. The NERVES that are spread over every part of the sensitive layer +of the true skin, proceed from the spinal cord. As a proof of the +great number of nervous filaments in the skin, no part of this tissue +can be punctured with a fine needle without transfixing a nerve, and +inducing pain. In some parts of the system, however, the nerves are +more abundant than in others; where the sense of feeling is most +acute, we find the greatest number of nerves, and those of the largest +size. Those parts that are most exposed to injury are most sensitive. + +_Examples._ 1st. The conjunctiva, or skin of the eye, is pained by the +presence of a particle of dust, because it would render vision +imperfect. + +2d. The lungs, also, would be injured by the smallest particle of +matter; they are therefore protected by the exquisite sensitiveness of +the lining membrane of the trachea, so that a particle of food or dust +is ejected by a convulsive cough before it reaches the lungs. + +627. The nerves are more numerous in the upper than lower extremities; +in greater numbers upon the palm than the back of the hand. They are, +likewise, more abundant and larger at the extremities of the fingers, +and in the lips, than in any other part of the skin. + +_Observation._ The proboscis of the elephant, the extremities of the +tails of certain species of monkeys, and the tentacula of some kinds +of fish, receive a more abundant supply of sensitive nerves than other +parts of their systems. + + -=-=-=-=-=-=-=-=-=-=-=-= + +626. Where do the nerves of the skin proceed from? Are they numerous +in this membrane? How is it proved? What is said of those parts most +exposed to injury? Give example 1st. Example 2d. 627. Mention the +difference in the distribution of the nerves in various parts of the +body. Is this difference found in the lower order of animals? + + -=-=-=-=-=-=-=-=-=-=-=-= + +628. In the small papillae, the nerve forms a single loop, while in +papillae of larger size, and endowed with a power of more exalted +sensation, the nerve is bent several times upon itself previous to +completing the loop. These little loops spring from a net-work of +nerves, imbedded in the upper porous layer of the true skin, at the +base of the papillae. This net-work of nerves receives its influence +through nerves which take their winding course through the fat +distended openings of the deeper layers of the true skin. + +[Illustration: Fig. 113. 1, 1, The cuticle. 2, 2, The colored layer of +the cuticle. 3, 3, The papillary layer, exhibiting the nerves as they +form loops. 4, 4, The net-work of nerves. 5, 5, The true skin. 6, 6, 6, +Three nerves that divide to form the net-work (4, 4.) 7, 7, 7, The +furrows between the papillae. 8, 8, 8, Three papillae magnified fifty +diameters.] + +629. The LYMPHATICS are found in great numbers in the true skin, and +they are so minute that they cannot be seen with the naked eye; but +when these hair-like vessels are injected with quicksilver, (a work of +great difficulty,) the surface injected resembles a sheet of silver. +In this way their existence can be imperfectly demonstrated. They are +a part of the vascular net-work situated upon the upper surface of the +true skin. Each papilla is supplied with a lymphatic filament, the +mouth of which opens beneath, and lies in contact with the under +surface of the cuticle. This net-work of vessels communicates through +the open meshes of the true skin with larger lymphatic trunks, that +open into the venous system. + + -=-=-=-=-=-=-=-=-=-=-=-= + +628. How are the nerves of the small papillae arranged? How in the +large papillae? What does fig. 113 represent? 629. What is said of the +cutaneous lymphatics? How is their existence proved? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 114. A plexus of lymphatic vessels in the skin, +considerably magnified from an injected preparation.] + +630. The OIL-GLANDS are small bodies imbedded in the true skin. They +connect with the surface of the skin by small tubes, which traverse +the cuticle. In some parts, these glands are wanting; in others, where +their office is most needful, they are abundant, as on the face and +nose, the head, the ears, &c. In some parts, these tubes are spiral; +in others, straight. These glands offer every shade of complexity, +from the simple, straight tube, to a tube divided into numberless +ramifications, and constituting a little rounded tree-like mass, about +the size of a millet seed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Of what are they a part? 630. Describe the oil-glands. With what do +they connect? Do they exist in every part of the body? Of what form +are their tubes? + + -=-=-=-=-=-=-=-=-=-=-=-= + +631. In a few situations, these small glands are worthy of particular +notice, as in the eyelids, where they possess great elegance of +distribution and form, and open by minute pores along the lids; in the +ear-passages, where they produce that amber-colored substance, known +as the _ce-ru'men_, (wax of the ears,) and in the scalp, where they +resemble small clusters of grapes, and open in pairs into the sheath +of the hair, supplying it with a pomatum of Nature's own preparing. +The oil-tubes are sometimes called the _se-ba'ceous fol'li-cles_. + +[Illustration: 4. A small hair from the scalp, with its oil-glands. The +glands (A) form a cluster around the shaft of the hair-tube, (C.) These +ducts open into the sheath of the hair, (B.) All the figures, from 1 to +4, are magnified thirty-eight diameters.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +631. What is said of these tubes in the eyelids? In the ear? In the +scalp? What are these glands sometimes called? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Among the inhabitants of cities, and especially in +persons who have a torpid state of the skin, the contents of the +oil-tubes become too dense and dry to escape in the usual manner. Thus +it collects, distends the tube, and remains until removed by art. When +this impacted matter reaches the surface, dust and smoke mix with it, +then it is recognized by small, round, dark spots. These are seen on +the forehead, nose, and other parts of the face. When this matter is +pressed out, the tube gives it a cylindrical form. The parts around +the distended tubes sometimes inflame. This constitutes the disease +called, _"ac'ne punc-ta'ta."_ + +632. The PERSPIRATORY APPARATUS consists of minute cylindrical tubes, +which pass inward through the cuticle, and terminate in the deeper +meshes of the cutis vera. In their course, each little tube forms a +beautiful spiral coil; and, on arriving at its destination, coils upon +itself in such a way as to constitute an oval-shaped, or globular +ball, called the _perspiratory gland_. + +633. The opening of the perspiratory tube on the surface of the +cuticle, namely, "the pores," is also deserving of attention. In +consequence of its extremity being a section of a spirally-twisted +tube, the aperture is oblique in direction, and possesses all the +advantages of a valvular opening, preventing the ingress of foreign +injurious substances to the interior of the tube and gland. + +634. "To arrive at something like an estimate of the value of the +perspiratory system, in relation to the rest of the organism, I +counted the perspiratory pores on the palm of the hand, and found 3528 +in a square inch. Now each of these pores being the aperture of a +little tube about a quarter of an inch long, it follows, that in a +square inch of skin on the palm of the hand there exists a length of +tube equal to 882 inches, or 73 1/2 feet. Surely such an amount of +drainage as seventy-three feet in every square inch of skin--assuming +this to be the average for the whole body--is something wonderful and +the thought naturally intrudes itself, What if this _drainage_ be +obstructed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is said of the retention of the unctuous matter in the oil-tubes? +632. Of what does the perspiratory apparatus consist? 633. What is +peculiar in the opening of the perspiratory tubes on the surface of +the cuticle? 634. How many perspiratory pores did Dr. Wilson count +upon a square inch of skin on the palm of the hand? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 116. A perspiratory gland from the palm of the hand, +magnified forty diameters. 1, 1, A twisted tube composing the gland. 2, +2, The two excretory ducts from the gland. These unite to form one spiral +tube, that perforates the cuticle, (3,) and opens obliquely on its +surface at 4. The gland is imbedded in cells filled with fat, which are +seen at 5, 5.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does fig. 116 represent? + + -=-=-=-=-=-=-=-=-=-=-=-= + +635. "Could we need a stronger argument for enforcing the necessity of +attention to the skin? On the pulps of the fingers, where the ridges +of the sensitive layer of the true skin are somewhat finer than in the +palm of the hand, the number of pores on a square inch a little +exceeded that of the palm; and on the heels, where the ridges are +coarser, the number of pores on the square inch was 2268, and the +length of the tube 567 inches, 47 1/4 feet. + +636. "To obtain an estimate of the length of tube of the perspiratory +system of the whole surface of the body, I think that 2800 might be +taken as a fair average of the number of pores in the square inch; and +consequently, 700, the number of inches in length. _Now, the number of +square inches of surface in a man of ordinary height and bulk is 2500; +the number of pores, therefore, 7,000,000; and the number of inches of +perspiratory tube is 1,750,000; that is, 145,833 feet, or 48,611 +yards, or nearly TWENTY-EIGHT miles!_"--_Wilson._ + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give other computations in this paragraph. 635. What is said of the +number of these pores on the pulp of the fingers? On the heels? 536. +What is an average number of pores and length of tube of the whole +surface of the body? Give the summary of the number of pores, and +number or inches of perspiratory tube. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXXII. + +PHYSIOLOGY OF THE SKIN. + + +637. The skin invests the whole of the external surface of the body, +following all its prominences and curves, and gives protection to all +the organs it encloses, while each of its several parts has a distinct +use. + +638. The cuticle is insensible, and serves as a sheath of protection +to the highly sensitive skin (_cutis vera_) situated beneath it. The +latter feels; but the former blunts the impression which occasions +feeling. In some situations, the cuticle is so dense and thick, as +wholly to exclude ordinary impressions. Of this we see an example in +the ends of the fingers, where the hard and dense nail is the cuticle +modified for the purpose referred to. Were the nervous tissue of the +true skin not thus protected, every sensation would be so acute as to +be unpleasant, and contact with external bodies would cause pain. + +639. The cuticle, also, prevents disease, by impeding the evaporation +of the fluids of the true skin, and the absorption of the poisonous +vapors, which necessarily attend various employments. It, however, +affords protection to the system only when unbroken, and then, to the +greatest degree, when covered with a proper amount of oily secretion +from the oil-glands. + +640. The cuticle is, originally, a transparent fluid, exuded by the +blood-vessels, and distributed as a thin layer on the surface of the +true skin. While successive layers are formed on the exterior of the +true skin, the external cuticular layers are converted into dry, +flattened scales, by the evaporation of their fluid contents. The +thickness of the cuticle is formed mainly from these scales. + + -=-=-=-=-=-=-=-=-=-=-=-= + +637-656. _Give the physiology of the skin._ 637. What is said of the +skin? 638. Give a function of the cuticle. Does it vary in thickness +on different parts of the body? Give examples. 630. Mention another +use of the cuticle. 640. What is the cuticle originally? + + -=-=-=-=-=-=-=-=-=-=-=-= + +641. The cuticle is, therefore, undergoing a constant process of +formation and growth at its under part, to compensate for the wear +that is taking place continually on its surface. A proper thickness of +the cuticle is in this manner preserved; the faculty of sensation and +that of touch are properly regulated; the places of the little scales, +which are continually falling off under the united influence of +friction and ablution, are supplied; and an action necessary, not +merely to the health of the skin, but to that of the entire body, is +established. + +642. Whenever the cuticle is exposed to moderate and repeated +friction, it becomes thicker and tougher, as may be seen in the +cuticle of the lady's finger that plies the needle and in the hard or +callous appearance of the hands of farmers masons, and other +mechanics. This enables them to handle the utensils and materials used +in their vocations without pain or inconvenience. + +_Observations._ 1st. When the joints of the feet are subjected to +moderate and continued pressure or friction, frequently one or more of +the papillae enlarge. This is accompanied with a thickening of the +layers of the cuticle, which is termed a "callosity," or "corn." These +thickened layers of the cuticle are broad at the top and narrow at the +bottom, and the enlarged mass is conical, with the point innermost. +When pressed upon by a tight shoe, these sensitive papillae cause +pain. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is the thickness of the cuticle mainly formed? 641. Describe the +changes of this membrane. Show the necessity of this constant growth. +642. How does moderate and repeated friction affect the cuticle? Give +examples. What is the benefit derived from having the cuticle thus +changed? What is the result if the joints of the feet are subjected to +moderate and continued pressure? What is the form of a "corn"? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. To remove these painful excrescences, take a thick piece of soft +leather, somewhat larger than the corn; in the centre punch a hole of +the size of the summit of the corn, spread the leather with adhesive +plaster, and apply it around the corn. The hole in the leather may be +filled with a paste made of soda and soap, on going to bed. In the +morning, remove it, and wash with warm water. Repeat this for several +successive nights, and the corn will be removed. The only precaution +is, not to repeat the application so as to cause pain. + +643. Let a person unaccustomed to manual labor, trundle the hand-cart, +or row a boat, for several successive hours, and the cuticle upon the +palms of the hands, instead of becoming thicker by use, is frequently +separated from the subjacent tissues, by an effusion of serum, +(water,) thrown out by the vessels of the true skin. Had the friction +been moderate, and applied at regular intervals, instead of blisters +being formed upon the inside of the hands, material would have been +thrown out to form new layers upon the lower surface of the cuticle. + +644. The cuticle is interesting to us in another point of view, +as being the seat of the color of the skin. The difference of +color between the blonde and the brunette, the European and the +African, lies in the cuticle;--in the deeper, and softer, and +newly-formed layers of that structure. In the whitest skin, the +cells of the cuticle always contain more or less of a peculiar +pigment, incorporated with the elementary granules which enter +into their composition. In the white races, the pigmentary tint +is extremely slight, and less in winter than in the summer season. +In the darker races, on the contrary, it is deep and strongly +marked. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How can they be removed? What precaution is given? 643. Explain why +those persons unaccustomed to labor, blister their hands in rowing a +boat or performing ordinary manual employment for several successive +hours. 644. In what other point of view is the cuticle interesting? In +what part of it do we find the coloring matter? + + -=-=-=-=-=-=-=-=-=-=-=-= + +645. The various tints of color exhibited by mankind, are, therefore, +referable to the amount of coloring principle contained within the +elementary granules of the cuticle, and their consequent depth of hue. +In the negro, the granules are more or less black; in the European of +the south, they are amber-colored; and in the inhabitants of the +north, they are pale and almost colorless. + +646. Color of the skin has relation to energy in its action; thus, in +the equatorial region, where light and heat are most powerful, the +skin is stimulated by these agents to vigorous action, and color is +very deep; while in the temperate regions, where light and heat are +not so intense, the lungs, liver, and kidneys relieve the skin of part +of its duties. The colored layer of the cuticle has been called the +_re'te mu-co'sum_, (mucous coat of the skin,) and described as a +distinct layer by many physiologists. + +_Observation._ "The various coloring of the inner layer of the cuticle +gives to some animals their varied hues; the serpent, the frog, the +lizard, and some fishes have a splendor of hue almost equal to +polished metal. The gold-fish and the dolphin owe their difference of +color and the brilliancy of their hues to the color of this layer of +the skin." + +647. The nerves of the skin are the organs of the sense of touch and +feeling. Through them we receive many impressions that enhance our +pleasures, as the grateful sensations imparted by the cooling breeze +in a warm day. In consequence of their sensitiveness, we are +individually protected, by being admonished of the proximity of +destructive agents. + + -=-=-=-=-=-=-=-=-=-=-=-= + +In what season of the year is the coloring matter less in the white +race? 645. To what is the color of the skin referable? 646. Why have +the races of the torrid zone darker complexions than those of the +temperate or frigid zones? What is this colored layer called by many +physiologists? To what is the different hues in animals owing? 647. Of +what use are the nerves of the skin? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ A man who had been afflicted some years with a severe +disease of a portion of the brain and spinal cord, was deprived of +feeling in the lower extremities. He was directed by his attending +physician to use a warm footbath. Intending to follow the directions +given him, he immersed his feet in boiling water, which he supposed of +a proper temperature. While his feet were immersed in the water, he +experienced no sensation of an unpleasant nature. On withdrawing them, +he was astonished to find the cuticle separated from the other +tissues, by the effusion of serum, and thus producing a blister over +the whole surface. + +648. Portions of the skin would suffer every day, were it not for the +sentinel-like care exercised by the nerves, by which all impressions +are transmitted to the brain. As the skin is continually exposed to +the influence of destructive agents, it is important that the nerves, +provided for its protection, should be kept in a healthy state. + +649. A large proportion of the waste of the body passes through the +outlets of the skin; some portions in the form of oil, others in the +form of water and carbonic acid. + +650. The oil-glands secrete an oil, partly free and diffused, and +partly mixed with albumen. When the cells are fully formed, that is, +fully distended, they yield their contents, and the fluid matter they +contain is set free, and passes along the tubes to the surface; this +fluid matter constitutes the oily element of the economy of the skin. + +651. The uses of the unctuous product of the oil-glands are twofold: +1st. The protection; 2d. The removal of waste matter from the system. +In the exercise of these offices the oily substance is diffused over +those parts of the skin which are naturally exposed to vicissitudes of +temperature and moisture,--as the nose, face, and head;--to the +injurious attrition of contiguous surfaces,--as the flexures of +joints;--or the contact of acrid fluids,--as in the excoriations to +which infants are liable. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give the illustration. 648. Why is it necessary that the cutaneous +nerves be kept in a healthy state? 649. Through what membrane does a +large proportion of the waste material of the system pass? 650. What +is the function of the oil-glands? 651. What are the uses of the oily +product of these glands? + + -=-=-=-=-=-=-=-=-=-=-=-= + +652. The oil of the unctuous substance is the principal agent in +effecting these purposes: 1st. It prevents the evaporation or +congelation of the water of the cuticle, which would cause it to +become parched and peel off, thus leaving the sensitive skin exposed. +2d. It affords a soft medium to the contact of moving substances. 3d. +It repels moisture and fluids. 4th. The action of these glands removes +the waste atoms and purifies the blood. + +653. In considering the purpose of the oily matter of the skin, there +are two situations in which it deserves especial remark. 1st. Along +the edges of the eyelids, where it is poured out in considerable +quantity. Here, it is the means of confining the tears and moisture of +the eyes within the lids, defending the skin from the irritation of +that fluid, and preventing the adhesion of the lids, which is liable +to occur upon slight inflammation. 2d. In the ears, where the unctuous +wax not only preserves the membrane of the drum and the passage of the +ear moist, but also, by its bitterness, prevents the intrusion of +small insects. + +654. The use of the perspiratory glands is to separate from the blood +that portion of the waste matter which is carried off through the skin +in the form of vapor. Sanctorius, a celebrated medical writer, daily, +for thirty years, weighed himself, his food, and excretions. He +estimated that _five_ of every _eight_ pounds of food and drink passed +from the system through the many outlets upon the skin. Many place the +estimate much lower. All physiologists agree that from twenty to forty +ounces of matter pass off from the skin of an adult every twenty-four +hours. + + -=-=-=-=-=-=-=-=-=-=-=-= + +652. What prevents the evaporation of the water of the cuticle? Give +its 2d use. Its 3d. Its 4th. 653. What is said in reference to the +distribution of the oily matter along the edges of the eyelids? In the +ears? 654. Of what use are the perspiratory glands? How long did +Sanctorius daily weigh his food, to ascertain the amount of secretion +that passed through the skin? + + -=-=-=-=-=-=-=-=-=-=-=-= + +655. The average amount of perspiration is about thirty ounces; and it +passes off in such minute portions, and mixes so rapidly with the +surrounding air, that it is not perceived. For this reason, it is +called _insensible_ perspiration. When this excretion is increased, it +forms into drops, and is called _sensible_ perspiration. The following +experiments prove the existence of this excretion from the skin. + +_Experiments._ 1st. Take a cold bell-glass, or any glass vessel large +enough to admit the hand, and introduce it perfectly dry; at the same +time close the mouth by winding a napkin about the wrist; in a short +time, the insensible perspiration from the hand, will be seen +deposited on the inside of the glass. At first, the deposit is in the +form of mist; but, if the experiment be continued a sufficient time, +it will collect in drops. + +2d. Hold the apparently dry hand near a looking-glass, and the +invisible vapor will soon be condensed, and cover the glass with a +slight dew. + +656. It is important that this excretion be maintained with steadiness +and regularity. When the action of the perspiratory glands is +suppressed, all the vessels of the different organs will suffer +materially, and become diseased, by the redundant waste matter that +should be carried from the system. If a person is vigorous, the action +of the organs, whose functions are similar to those of the skin, as +channels for the exit of waste matter, will be increased, and thus +relieve the diseased state of the body. But the over-taxing of these +organs, to relieve the system, often produces a diseased action in +themselves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What were his conclusions? 655. What is the average amount of +perspiration every twenty-four hours? What is insensible perspiration? +What is sensible perspiration? How can the existence of the excretion +of the skin be shown? Give the 2d experiment. 656. Why is it important +that these excretions be maintained regularly? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 117. 1, 1, The lines, or ridges of the cuticle, cut +perpendicularly. 2, 2, 2, 2, 2, The furrows, or wrinkles of the same. 3, +The cuticle. 4, 4, 4, The colored layer of the cuticle. 5, 5, The cutis +vera. 6, 6, 6, 6, 6, The papillae. 7, 7, Small furrows between the +papillae. 8, 8, 8, 8, The deeper furrows between each couple of the +papillae. 9, 9, Cells filled with fat. 10, 10, 10, The adipose layer, with +numerous fat vesicles. 11, 11, 11, Cellular fibres of the adipose tissue. +12, Two hairs. 13, A perspiratory gland, with its spiral duct. 14, +Another perspiratory gland, with a duct less spiral. 15, 15, Oil-glands +with ducts opening into the sheath of the hair, (12.)] + +_Note._--Let the pupil review the anatomy and physiology of the skin +from Fig. 117 or from anatomical outline plate No. 9. + + + + +CHAPTER XXXIII. + +HYGIENE OF THE SKIN. + + +657. The sensibility of the skin, and the activity of the oil and +perspiratory glands, are modified by the condition of the cuticle, the +temperature of the skin and body, the purity and warmth of the air, +and the character of the light to which the body is exposed. Thus, to +maintain a healthy action of every part of this membrane, attention +should be given to _Clothing_, _Bathing_, _Light_, and _Air_. + +658. CLOTHING, in itself, does not bestow heat, but is chiefly useful +in preventing the escape of heat from the body, and in defending it +from the temperature of the atmosphere. In selecting and applying +clothing to our persons, the following suggestions should be +observed. + +659. _The material for clothing should be a bad conductor of heat_; +that is, it should have little tendency to conduct or remove heat from +the body. This depends mainly on the property possessed by the +material in retaining atmospheric air in its meshes. + +660. _The material for clothing should not possess the property of +absorbing and retaining moisture._ Dampness, or moisture, renders +apparel a good conductor of heat; beside, if the perspired fluid, and +the saline material it holds in solution, are readily absorbed by the +clothing, they become sources of irritation to the skin with which +the apparel comes in contact. + + -=-=-=-=-=-=-=-=-=-=-=-= + +657-716. Give the hygiene of the skin. 657. What influences modify the +action of the oil and perspiratory glands? To what must attention be +given to maintain a healthy action of the skin? 658. What is said in +regard to the clothing? 659. Mention a property that the material for +clothing should possess. 660. What property in the selection of +clothing should we avoid? Why? + + -=-=-=-=-=-=-=-=-=-=-=-= + +661. _Furs_ contain a greater amount of air in their meshes, than any +other article, and they absorb no moisture; consequently, as an +article of dress, they are best adapted to those who are exposed to +great vicissitudes of heat and cold. + +662. _Woollen cloth_ retains more air in its meshes than any other +article except furs and eider down, and it absorbs but very little +moisture. These properties, together with its comparative cheapness, +render it a good article of apparel for all classes of persons. The +only objection to its general use is, the disturbance of the +electricity of the system, and the irritation to delicate skins from +the roughness of its fibres. + +_Observation._ Flannels are not only beneficial, during the cold +season, in preventing colds and rheumatism, but they are of great +utility in the warm season, in shielding the system from the chills at +evening, that induce disease of the alimentary canal. Their general +use among children and delicate females, would be a preventive of the +"season complaints" prevalent in the months of August and September. + +663. _Cotton_ contains less air in its meshes than woollen, but much +more than linen. In texture, it is smoother than wool, and less liable +to irritate the skin. This fabric absorbs moisture in a small degree. +In all respects, it is well adapted for garments worn next the skin. +When woollen flannels irritate the skin, they may be lined with +cotton. + +664. _Silk_ is not as good a conductor of heat as cotton, nor does it +absorb moisture to any considerable degree; its texture is smooth, and +does not irritate the skin; consequently, when the garment of this +fabric has sufficient body or thickness, it is a good article for +clothing. The greatest objection to its use is the disturbance of the +electricity of the system, and its high price. + + -=-=-=-=-=-=-=-=-=-=-=-= + +661. Give the properties of fur. As an article of dress, to whom are +they best adapted? 662. Give the properties of woollen cloth. Is this +a good article for clothing? What objection? What are the advantages +of wearing flannels? 663. What are the qualities of cotton as an +article of dress? 664. Of silk? + + -=-=-=-=-=-=-=-=-=-=-=-= + +665. _Linen_ is not only a good conductor of heat, and consequently +a poor article of apparel, but it likewise absorbs the fluids +carried from the system by the agency of the oil and perspiratory +glands. When garments are made of this material, the body is not +surrounded by a layer of air, but by one of moisture. This still +further increases its power to conduct heat from the system, +rendering it a very objectionable article of apparel, even in warm +weather and in hot climates, where the dress is usually thin. + +666. _Clothing differs in its power of radiating heat._ This is +influenced by the color; those articles that radiate heat freely also +absorb it readily. A black surface is a good radiator, while a white +surface is not, because it reflects the calorific rays. It is obvious +that those colors which render the transmission of external heat +difficult, must impede the transmission of caloric from the body. Thus +it is manifest, that light-colored apparel is best adapted for every +season and every climate. + +_Observation._ Coach-drivers are practically aware, that in cold +weather, light-colored over-coats are warmest, except when they are +exposed to the direct rays of the sun, or when seated before a +warm fire. On the other hand, when the temperature is elevated, +light-colored apparel is coolest, because the sun's rays are then +reflected. + +667. _The clothing should be of a porous character._ The skin is not +only an important agent in separating from the blood those impurities +that otherwise would oppress the system and occasion death, but it +exercises great influence upon the system, by receiving oxygen through +its tissues, and giving back carbonic acid in return. Consequently, +the apparel should be made of a material that will permit free +transpiration from the skin, and likewise convey the excreted fluids +from the surface. + + -=-=-=-=-=-=-=-=-=-=-=-= + +665. What is said of linen as an article of apparel? 666. Why is +light-colored apparel best adapted for every season? What is said of +the apparel of coach-drivers? 667. Why should we wear porous +clothing? + + -=-=-=-=-=-=-=-=-=-=-=-= + +668. The necessity for this is illustrated in wearing India rubber +over-shoes. If they are worn over boots ten or twelve hours, not only +the hose, but the boots will be moist from retained perspiration, and +the residual matter left in contact with the skin may be reconveyed +into the system by absorption, causing headache and other diseases. +Cotton and woollen fabrics are not only bad conductors of heat, but +are also porous; for these reasons, they are well adapted to transmit +the excretions of the skin. + +669. _The clothing should be not only porous, but fitted loosely._ The +garments should retain a layer of air between them and the body. Every +one is practically aware that a loose dress is much warmer than one +which fits closely; that a loose glove is warmer than a tight one; and +that a loose boot or shoe affords greater warmth than one of smaller +dimensions. The explanation is obvious; the loose dress encloses a +thin layer of air, which the tight dress is incapable of doing; and +what is required, is, that the dress should be closed at the upper +part, to prevent the dispersion of the warm air, by the ventilating +current which would be established from below. + +_Observation._ As the purpose of additional garments is to maintain a +series of strata of warm air within our clothing, we should, in going +from a warm room into the cold air, put on our defensive coverings +some little time previous, in order that the layers of air which we +carry with us may be sufficiently warmed by the heat of the room, and +not borrowed from the body on exposure to the cold. + + -=-=-=-=-=-=-=-=-=-=-=-= + +668. How is the necessity of porous clothing illustrated? 669. Why +should we wear loose garments? What is the use of additional garments +when going from a warm to a cold air? When should they be put on? + + -=-=-=-=-=-=-=-=-=-=-=-= + +670. _The clothing should be suited to the temperature of the +atmosphere and the condition of the individual._ The invariable rule +should be, to wear enough to maintain an equal and healthy action of +the skin. Care should be taken, however, that the action of the +cutaneous vessels is not inordinately increased, as this would +debilitate, not only the skin, but the internal organs of the system, +as the stomach and lungs. + +671. No rule as to the quantity of clothing can be given, as the +demand will vary with different individuals. The following are among +the most prominent causes of this variation: Those persons who have +large, active brains, full chests, well developed lungs, breathe an +adequate amount of pure air, and take sufficient food to supply the +wants of the system, require less clothing than those of an opposite +character, because more heat is generated in the system. + +672. _The child and the aged person require more clothing than the +vigorous adult._ "Should we judge from observation, the inference +would be, that children require less clothing than adults. This is an +error, for the temperature in infancy is not only lower than in +manhood, but the power of creating heat is feebler. The same remarks +are applicable to those persons who have outlived the energies of +adult life." + +_Observation._ The system of "hardening" children, by an inadequate +supply of clothing, and keeping them uncomfortably cold throughout the +whole day, is inhuman, as well as unprofitable. It operates upon the +child somewhat like the long-continued chill upon a certain portion of +the farmer's herd, that are kept shivering under the thatched shed, +retarding the growth of their systems, which require more food to +satisfy the keen cravings of hunger than when they are comfortably +sheltered. To make the boy robust and active, he must have nutritious +food at stated hours, and free exercise in the open air, and his +system must be guarded from chills by a due amount of apparel. + + -=-=-=-=-=-=-=-=-=-=-=-= + +670. What should be the invariable rule in reference to the amount of +clothing that should be worn? What precaution should be observed? 671. +What are some of the causes of the variation of the demand for +clothing? 672. Why do the child and aged person require more clothing +than the vigorous adult? What is said of the system of hardening +children? + + -=-=-=-=-=-=-=-=-=-=-=-= + +673. _More clothing is needed when a vital organ is diseased._ It may +be observed that in consumption, dyspepsia, and even in headache, the +skin is pale and the extremities cold, because less heat is generated. +Thus persons affected with these complaints, when exposed to cold air, +need more clothing than those individuals whose organs are not +diseased, and the functions of which are properly performed. + +674. _More clothing is required in the evening, than during the day._ +In the evening we have less vital energy, and therefore less heat is +generated in the system, than in the early part of the day; beside, +the atmosphere is damp, the skin has become moist from free +perspiration, and heat, in consequence, is rapidly removed from the +system. For this reason, when returning from crowded assemblies, we +should be provided with an extra garment. + +_Observations._ 1st. If there is a chill upon the system after having +arrived home, warmth should be restored as speedily as possible. This +can be done by friction with warm flannels, and by using the warm or +vapor bath. By this procedure, the pernicious effects of the chill +will be prevented before any disease is fixed upon the system. Is it +not the duty of the parent and the guardian to learn these facts, and +to see that they are not only learned, but reduced to practice? + +2d. The farmer and industrious mechanic would be freed from many a +rheumatic pain, if, while resting from their labors at evening, or +taking the ordinary meal after hard toil, they would put on an extra +garment. The coat might not feel so agreeable for the first few +minutes, but it would ultimately conduce to health and longevity. + + -=-=-=-=-=-=-=-=-=-=-=-= + +673. Why do dyspeptic and consumptive persons require more clothing +than those who have healthy vital organs? 674. Why do we need more +clothing in the evening than during the day? How can the pernicious +effects of a chill be prevented? Give the 2d observation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +675. _The person of active habits requires less clothing than one of +sedentary employments._ Exercise increases the circulation of the +blood, which is always attended by the disengagement of a greater +quantity of heat; consequently, an increase of warmth is felt +throughout the system. We likewise need more clothing while riding, +than when we are walking; because the exercise of the former is less +than that of the latter. The same is true when resting in the field or +shop, after laborious exercise. + +_Observation._ We need a greater amount of clothing while asleep, than +during the day; as not only the action of the body, but that of the +brain, during sleep, is suspended. + +676. _Less clothing is required when the cutaneous surface is clean._ +A film of impurities obstructs the perspiratory ducts, and diminishes +the action of their glands; consequently, less heat is generated. For +this reason, the hands or feet when clean are less liable to become +chilled or frozen. + +677. _The sensitiveness of the skin to the influence of cold, is much +modified by habit._ A person who has been habituated to the +temperature of a warm room, or warm climate, suffers more when exposed +to cold, than an individual who has been accustomed to colder air. +Thus a person who labors or studies in a warm room, should wear more +clothing when exposed to the air, while walking or riding, than an +individual who labors in a cooler atmosphere. Not only is the +sensibility of the skin increased by a warm atmosphere, but the +activity of the digestive, respiratory, and nervous systems, in +generating heat, is much diminished. This is an additional reason why +an increased amount of clothing is demanded during exposure to cold +air. In all cases where practicable the heat of the system should be +maintained by exercise, in preference to the use of fur or flannel. + + -=-=-=-=-=-=-=-=-=-=-=-= + +675. Why does the person of active habits require less clothing than +one of sedentary employments? 676. Why do we need less clothing when +the skin is clean? 677. Show the effect of habit on the sensitiveness +of the skin. + + -=-=-=-=-=-=-=-=-=-=-=-= + +678. _Those parts of the skin usually covered, uniformly need that +protection._ The power of generating heat is diminished, and the +impressibility to cold is increased, on those portions of the skin +usually clothed. If a person wears the dress high and close about the +neck, he suffers from exposure to a cold atmosphere if a dress is worn +that is not as high or more open. As a general rule, it is preferable +that those parts of the system, as the larynx, be exposed that are not +uniformly protected by clothing. + +679. _The clothing should be kept clean._ No article of apparel is +entirely free from absorption; even wool and cotton possess it in a +small degree. They take up a portion of the transpired fluids which +contain saline and animal matter, and thus the fibres of the garments +become covered with the cutaneous excretions. We are practically aware +of the retention of these secretions from the soiled appearance of +those garments worn next the skin, which are so covered as to preclude +the particles of dust from lodging upon them. + +680. The porosity of the clothing is lessened when soiled, and its +power of conducting heat from the system in consequence, is increased. +The residual matter with which the clothing is coated is brought in +contact with the skin, which causes irritation, and not unfrequently +re-absorption of the elements, thrown off from the system through this +avenue. Hence warmth, cleanliness, and health require that the +clothing, particularly the garments worn next to the skin, should be +frequently and thoroughly washed. This should not be forgotten in +regard to children, for their blood circulates with greater rapidity +than that of adults, and a proportionably greater amount of waste +matter is thrown off from their systems. + +681. _The under-garments worn during the day should not be worn at +night, or the reverse._ When under-garments are worn several +successive days or nights, they should not be put in drawers, or hung +up in a close closet, as soon as taken from the body, but should be +exposed to a current of air. + +682. _Occupied beds should be thoroughly aired in the morning._ The +excretions from the skin are most abundant during the hours of +sleep; and if the sheets and blankets, together with the bed, are +not aired every morning, by being so arranged that both surfaces +may be exposed to the air, the materials eliminated from the skin will +be retained in the meshes of the bed-clothing, and may be conveyed +into the system of the next occupant, by absorption. Oftentimes +diseases of a disagreeable nature are contracted in this way. This +fact should be instilled into every mother's and daughter's mind. + +_Observation._ Bed-linen should not be put on a bed when it is not +sufficiently dried, or contains moisture from the excretions of the +skin, nor should beds or bedding be slept in, that have remained in a +damp room that has not been occupied for many weeks, unless the +dampness is removed from the bed-linen by a warming-pan, or in some +other way. + +683. _Changes of dress, from thick to thin, should always be made in +the morning._ At this time the vital powers are usually in full play. +Many a young lady has laid the foundation of a fatal disease, by +disregarding this rule, in exchanging the thick dress, with woollen +stockings, for the flimsy dress and hose of silk or cotton, which are +considered suitable for the ball-room or party. Sudden changes in +wearing-apparel, as well as in food and general habits, are attended +with hazard; and this is proportionate to the weakness or exhaustion +of the system when the change is made. + + -=-=-=-=-=-=-=-=-=-=-=-= + +681. Should the garments worn during the day be worn at night? 682. +What is said respecting the cleanliness of beds and bedding? Why +should not bed-linen that is damp be slept in? 683. When should change +of dress from thick to thin be made? Why? + + -=-=-=-=-=-=-=-=-=-=-=-= + +684. _When the clothing has become wet, it is best to change it +immediately._ The skin should then be rubbed with a dry crash towel, +until reaction, indicated by redness, is produced. If the garments are +not changed, the person should exercise moderately, so that sufficient +heat may continue to be generated in the system to dry the clothing +and skin without a chill. Sitting in a cool shade, or current of air, +should, by all means, be avoided; as colds are not contracted by free +and excessive exercise, but by injudicious management after such +exercise. + +_Observation._ When an individual has been thrown into a profuse +perspiration by violent exercise, though the skin and clothing may +become wet, he feels no inconvenience from the dampness, as long as he +continues that amount of exercise for the reason that the circulation +of the blood being increased heat is generated in sufficient quantity +to replace the amount abstracted from the system in evaporating the +free perspiration; but as soon as the exercise is discontinued, the +increased circulation subsides, and with it the extra amount of +generated heat. This accounts for the chill we experience, when the +damp clothing is permitted to dry on the body, after the cessation of +exercise. + + -=-=-=-=-=-=-=-=-=-=-=-= + +684. What suggestion when the clothing has become wet? What should be +done if the garments are not changed? What causes the chill that is +experienced when damp clothing is permitted to dry on the body? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXXIV. + +HYGIENE OF THE SKIN, CONTINUED. + + +685. Bathing, its necessity and expediency, is obvious from the +structure and the functions of the skin. The cuticle is cast off in +minute, powdery scales, many of which are retained upon the surface by +the pressure of clothing. These mingle with the oily and saline +products of the skin, and form a thin crust. This crust, on account of +its adhesiveness, collects particles of dust and soot from the +atmosphere, and particles of foreign matter from our dress; so that in +the course of the day the whole body becomes coated with impurities. +If this coating remains, becomes thick and established upon the skin, +it will produce the following effects:-- + +686. 1st. _The pores will be obstructed, consequently transpiration +impeded, and the influence of the skin as an excretory entirely +prevented._ When the pores are obstructed, and transpiration is +checked, the elements of the transpired fluids will necessarily be +retained in the system; and, as they are injurious and poisonous if +retained, they must be removed by those organs whose functions in the +animal economy are similar, as the lungs, kidneys, liver, intestines, +&c. + +687. When these organs are called upon to perform their offices, and +in addition that of another, the healthy equilibrium is destroyed, and +the oppressed organ will suffer from exhaustion, and become the prey +of disease. Thus, obviously, habits of uncleanliness are a cause of +consumption and other serious diseases of the vital organs. Again, +obstruction of the pores will prevent respiration through the skin, +thus depriving the blood of one source of its oxygen, and one outlet +of its carbonic acid, which will diminish the temperature of the +system, and the same results follow as when the clothing is +inadequate. + + -=-=-=-=-=-=-=-=-=-=-=-= + +685. Show the necessity for bathing. 686. What effect upon the body if +the pores of the skin are obstructed? 687. What is the effect when an +organ not only performs its own specific function, but that of +another? + + -=-=-=-=-=-=-=-=-=-=-=-= + +688. 2d. _The retained perspirable matter will irritate the skin, both +mechanically and chemically_; and this membrane will be kept damp and +cold, from attraction and detention of moisture; and foreign material, +as before adverted to, once removed from the system, may be reconveyed +into it by absorption. As a consequence, cutaneous eruptions and +diseases will be produced, and the re-absorption of matter once +separated from the system, will be the exciting cause of other +injurious disorders. + +689. 3d. _A film of foreign substance on the skin will inevitably +become the seat of detention of miasmata and infectious vapors._ These +will remain until absorbed, and engender the diseases of which they +are the peculiar cause. This is one reason why filthy persons contract +infectious diseases more frequently than individuals of cleanly +habits. + +690. _Bathing is useful to promote cleanliness._ In this capacity, it +enables us to remove the coating of impurities from the exterior of +our persons. It effects this purpose by dissolving saline matters, and +holding in temporary suspension those substances which are insoluble. + +691. The cuticle is composed of a substance resembling the dried white +of egg, or, in a word, _albumen_. This is soluble in alkalies, and +these are the agents which are commonly employed for purifying the +skin. Soap is a compound of the alkali soda with oil, the former being +in excess. When used for washing, the excess of alkali combining with +the oily fluid, with which the skin is naturally bedewed, removes it, +in the form of an emulsion, and with it a portion of any adhering +matter. Another portion of the alkali softens and dissolves the +superficial layer of the cuticle; and when this is removed the cuticle +is free from impurities. + + -=-=-=-=-=-=-=-=-=-=-=-= + +688. How are cutaneous eruptions frequently produced? 689. How are +infectious vapors transmitted to the system? 690. How does bathing +promote cleanliness? 691. Why is it necessary to use soap in bathing? + + -=-=-=-=-=-=-=-=-=-=-=-= + +692. Every washing of the skin with soap removes the old face of the +cuticle, and leaves a new one; and were the process repeated to +excess, the latter would become so thin as to render the body sensible +to impressions too slight to be felt through its ordinary thickness. +On the other hand, when the cuticle and its accumulated impurities are +rarely disturbed, the sensitiveness of the skin is impaired. The +proper inference to be drawn from the preceding remarks, is in favor +of the _moderate_ use of soap to cleanse the skin. + +_Observation._ If any unpleasant sensations are felt after the use of +soap, they may be immediately removed by washing the surface with +water slightly acidulated with lemon juice or vinegar, which +neutralizes the alkali that may remain on the skin. This is effective +treatment for "chapped hands." + +693. _Bathing may be partial or general, and the water used may be +cold, temperate, tepid, warm, or hot._ A person may apply it to his +system with a sponge, it may be poured upon him, or he may immerse +himself in it. The simplest mode of bathing is to apply water to a +small extent of surface, by means of a wet sponge, and after being +wiped dry, again cover with the dress. In this way the whole body may +be speedily subjected to the influence of water, and to no less useful +friction. The water used may be warm or cold. This species of bathing +may be practised by any invalid, and always with benefit, if the +bathing is succeeded by a glow of warmth over the surface; and this is +the test by which the benefit of all forms of bathing is to be +estimated. + + -=-=-=-=-=-=-=-=-=-=-=-= + +692. Why should only a moderate amount of soap be used in bathing? If +unpleasant sensations are felt from too free use of soap, how can they +be counteracted? 693. Give the different forms of bathing. What is the +simplest mode of bathing? Can this mode be adopted by invalids with +safety? + + -=-=-=-=-=-=-=-=-=-=-=-= + +694. When the heat of the system is adequate, the bather may stand or +sit in a shallow tub, while he receives the water from a sponge +squeezed over the shoulders or against the body. In this form of +bathing, the person is more exposed to the cold air, and on this +account it is less suitable for very feeble individuals than the +first-mentioned method. In the early use of this form of the +sponge-bath, the bather should content himself with a single affusion +from the sponge; the body should be quickly wiped with a soft towel, +and friction applied with a crash towel or a brush. + +695. The third kind of bathing is that of the shower-bath, which +provides a greater amount of affusion than the former, combined with a +greater shock to the nervous system. The concussion of the skin by the +fall of water, particularly distinguishes this from the previous modes +of bathing. The degree of concussion is modified by the size of the +openings through which the water issues, and the height of the +reservoir. The shower-bath admits of modification, adapting it to the +most delicate as well as the robust. The extent of fall, the size of +the apertures, the quantity and temperature of the water, may be +regulated at pleasure. + +_Observation._ In using the shower-bath, it would be judicious to +commence with warm or tepid water, for which, by a gradual process, +cold water may be substituted. In this way the system may be inured to +cold water. After bathing, the skin should be wiped dry and rubbed +briskly. + +696. The fourth form of bathing is that in which the body, or a +portion of it, is immersed in water. The temperature of water in this +form of bathing may be modified according to the sensations and +purposes of the bather. This form of bathing is designated according +to the heat of the water. When the temperature is below 75 deg., it is +termed a cold bath; when from 75 deg. to 85 deg., a temperate bath; from +85 deg. to 95 deg., a tepid bath; from 95 deg. to 98 deg., a warm bath; +from 98 deg. to 105 deg., a hot bath. In using this form of bathing, the +skin should be wiped perfectly dry, and briskly rubbed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is the test by which to estimate, the benefit of all modes of +bathing? 694. Give another method of sponge-bathing. 695. What is said +of the shower-bath? What caution is given? 696. Give the fourth form +of bathing. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ The length of time a person may remain in a cold bath +with benefit varies from two to ten minutes; while a person may remain +in a temperate, tepid, or warm bath, from ten to thirty minutes, or +until special indications are exhibited. + +697. In the vapor-bath, the vapor is not only applied to the exterior +of the system, but it is inhaled and brought in contact with every +part of the interior of the lungs. The bather is seated upon a chair, +and the vapor gradually turned on around him, until the proper +temperature (90 deg. to 110 deg.) is attained. The bath may be continued +from ten to thirty minutes. After leaving the bath, attention should be +given to the skin, as in other forms of bathing. + +698. In order to increase and promote reaction of the skin, various +measures and processes are used, some of which are practised in, and +others after, quitting the bath. Of the former, the rubbing and +brushing the skin are the most common and important. The brisk and +efficient friction of the skin with a coarse towel and flesh-brush, +after quitting the bath, should never be omitted. This short catalogue +embraces all the appliances requisite for the purpose. + +699. _Bathing promotes health by its immediate and remote physiological +effects on the system._ When the body is moistened with a sponge wet +with cold water, or when an affusion by the sponge or shower-bath is +used, the skin instantly shrinks, and the whole of its tissue +contracts. This contraction diminishes the capacity of the cutaneous +system of blood-vessels, and a portion of the blood circulating through +them is suddenly thrown upon the more internal parts of the body. +The nervous system, among others, participates in it, and is stimulated +by the afflux, and communicates its stimulus to the whole system. +This causes a more energetic action of the heart and blood-vessels, and +a consequent rush of blood back to the skin. This is the state +termed _reaction_, the first object and purpose of every form of +bathing. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What degree of temperature of water is termed a cold bath? A +temperate? A tepid? A warm? A hot bath? State the length of time that +a person should remain in the different baths. 697. What is said of +the vapor bath? 698. Mention the different methods for promoting +reaction of the skin. + + -=-=-=-=-=-=-=-=-=-=-=-= + +700. This condition of the skin is known by the redness of the +surface, the glow, comfort, and warmth which follow the bath. The +bather should direct all his care to insure this effect. By it the +internal organs are relieved, respiration is lightened, the heart is +made to beat calm and free, the mind is clear and strong, the tone of +the muscular system is increased, the appetite is sharpened, and the +whole system feels invigorated. This is the end and aim of the bather, +and to this all his training tends. The error is, to expect the result +without the preparation. + +701. In order to promote reaction, and to be efficient in preserving +health, bathing should be regular, should be commenced by degrees, and +increased by a process of training, and should not be permitted to +intrude upon hours devoted to some important function, as digestion. +It must not precede or follow too closely a meal, or severe mental or +muscular exercise, as reaction is less certain and vigorous when +important internal organs are employed, than when they are at rest. +When the vital powers are greatest, and the system most free from +exhaustion, bathing is most beneficial; hence the morning is +preferable to the evening, and the middle of the forenoon to the +middle of the afternoon, for this healthful and agreeable duty; as the +vital action of the system is most energetic in the early part of the +day. + + -=-=-=-=-=-=-=-=-=-=-=-= + +699. What is the effect upon the skin when cold water is applied? What +is the first object and purpose of every form of bathing? 700. How is +this condition of the skin known? Mention the salutary effects that +this condition has on the body. 701. How should bathing be performed, +in order to be efficient in preserving health? + + -=-=-=-=-=-=-=-=-=-=-=-= + +702. In regard to the frequency of bathing, the face and neck, from +their necessary exposure to the atmosphere, and the impurities which +the latter contains, should receive at least two washings in +twenty-four hours, one of which should be with soap; the feet, from +the confined nature of the coverings which are worn over them, require +at least one; the armpits, from the detention, as well as from the +peculiar properties of the secretions, at least one; and the hands and +arms, as many as seem proper. The whole person should be bathed at +least every second day, but the most perfect health of every part of +the body would be maintained, if the excretions from the skin were +removed daily. + +703. In diseases of the skin and internal organs, bathing is a +remedial measure of great power. It should never be neglected or +omitted. It is not only pleasant and safe, but is really more +effective than any medicine administered internally. This, like other +curative means, should be applied by the direction and under the eye +of the medical adviser, that it may be adapted to the condition of the +patient. + +704. "From the first hour of man's existence to his latest breath, in +health and in sickness, rich or poor, water is always requisite. Baths +were dedicated by the ancients to the divinities of medicine, +strength, and wisdom, namely, AEsculapius, Hercules, and Minerva, to +whom might properly be added the goddess of health, Hygeia. The use of +water has been enforced as a religious observance, and water has been +adopted as one of the symbols of Christianity." + + -=-=-=-=-=-=-=-=-=-=-=-= + +When should bathing be performed? 702. How often should we bathe? 703. +What is said of bathing in disease? Who should direct the kind of bath +proper in different diseases? 704. Were baths dedicated by the +ancients? + + -=-=-=-=-=-=-=-=-=-=-=-= + +705. The AIR is an agent of importance in the functions of the skin. +It imparts to this membrane oxygen, and receives from it carbonic +acid. It likewise removes from it a large portion of the perspiration +and the more fluid portions of the oily secretion. In order that the +air may accomplish these ends, it is necessary that it come in contact +with the body. This is one of the many reasons why we should wear +loose and porous clothing. + +706. Again, the air should be pure, and free from redundant moisture. +In the warm mornings of July and August, the air is loaded with +moisture and impurities, and the perspirable matter is not removed +from the system as it is when the air is pure and dry. This is the +cause of the general lassitude that is experienced during such +mornings. As soon as the fog is dispelled, these unpleasant sensations +are removed. To sustain the functions of the skin in a healthy state, +the parlor, kitchen, sleeping-room, school-house, and work-shop, +should be well ventilated. The blood of the system will be purer, and +its color of a brighter scarlet, if the skin is surrounded by fresh +and pure air, than when it is foul or moist. + +707. The LIGHT permeating the skin, not only exercises a salutary +influence upon this membrane, but upon the blood, and, through this +fluid, upon the whole system. For this reason, the kitchen and the +sitting-room, which are the apartments most used by ladies, should be +selected from the most pleasant and well-lighted rooms in the house. +On the other hand, dark rooms and damp cellar-kitchens should be +avoided, as exercising an injurious influence upon both body and +mind. + +708. The dark, damp rooms, so much used in cities and large +villages, by indigent families and domestics, are fruitful causes +of disease, as well as of vice, poverty, and suffering. Common +observation shows that solar light also exercises much influence +upon the vigor and color of vegetables. Plants that are kept in +well-lighted rooms, have darker and more brilliant colors than +those that grow in darkened apartments. + + -=-=-=-=-=-=-=-=-=-=-=-= + +705. Give the reasons why pure air should be supplied to the skin. +706. What is the cause of the general lassitude in a damp, warm +morning? 707. Show the salutary effects of light on the skin. 708. +What is one cause of disease and suffering in large villages? + + -=-=-=-=-=-=-=-=-=-=-=-= + +709. BURNS and SCALDS are terms applied to those conditions of the +skin which are produced by the application of an undue amount of heat, +which changes the action of its vessels. + +710. A small degree of heat will irritate the nerves, and cause an +increased action of the blood-vessels. This is attended with severe +smarting pain, and will be followed by the deposition of serum under +the cuticle, unless applications are made immediately, to prevent +vesication, or blistering. To prevent or suppress this state of +arterial action, wet some folds of cotton or woollen cloth with cold +water, and apply them to the parts scalded; continue to apply cold +water, so as to steadily maintain the low temperature of the +applications, as long as the _smarting pain_ is experienced. The +steady application of cold dressing also tends to prevent an increased +action of the blood-vessels, and will suppress it, if it already +exist. + +711. When blisters are formed, the cuticle is separated from the other +tissues of the skin by the effusion of serum. In all cases, if this +layer of the skin is not removed, a small opening should be made in +the raised cuticle, by which the serum deposited may be removed. Under +such circumstances, never remove the cuticle, as it makes the best +possible covering for the blood-vessels and nerves of the true skin. +The cold water dressing, recommended in the preceding paragraph, may +then be applied as long as the smarting sensation continues. After the +pain has subsided, the blistered part may be covered by a patch of +cotton or linen cloth, upon which an ointment, made of lard and +bees-wax, has been spread. + + -=-=-=-=-=-=-=-=-=-=-=-= + +709. To what condition of the skin are the terms burns and scalds +applied? 710. What is the effect when only a small degree of heat is +applied to the skin? How can vesication be prevented? 711. What should +be the treatment when blisters are formed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +712. If the cuticle has been removed, there will be much suffering, +because the nerves are unduly stimulated by the air. The cuticle is +the sheath or covering of the vessels and nerves of the skin, and when +it is removed, a substitute should be applied. This substitute should +be soothing, and cover the denuded surface. Linseed-meal or ground +slippery-elm bark poultice, fresh cream, or lard and bees-wax, spread +upon linen or cotton cloth, would make a good dressing. When dressings +are applied, they should not be removed until they become dry and +irritating. + +713. If there is much suffering, administer to an adult from +twenty-five to sixty drops of laudanum, according to the severity of +the pain. If the patient is a child, from fifteen drops to a +tea-spoonful of paregoric may be administered. When there is much +prostration, some hot peppermint tea or other stimulant may be found +necessary to bring on reaction. + +714. The hands, feet, ears, &c., are subject, in cold latitudes, to be +_frozen_, or _frost-bitten_. This may occur when the patient, at the +moment, is not aware of it. The part affected at first assumes a dull +red color, which gradually gives place to a pale, waxy appearance, and +becomes quite insensible. The first thing to be done in such cases, is +to reestablish circulation. This should be effected very gradually. If +a large quantity of blood is thrown suddenly into the chilled and +debilitated vessels of the frozen part, inflammation may be produced +that will destroy the vitality of the limb. + + -=-=-=-=-=-=-=-=-=-=-=-= + +712. That should be the treatment if the cuticle has been removed? How +often should the dressing of burns be removed? 713. What may be +necessary when there is much suffering? 714. What is the appearance of +limbs while freezing? How should the circulation be at first +reestablished? What should be avoided? + + -=-=-=-=-=-=-=-=-=-=-=-= + +715. The circulation and sensibility may be restored by rubbing the +frozen limb, with snow, or, when this is not to be obtained, cold +water; but snow is always to be preferred. The fire should be avoided; +and it would be better for the patient to be kept in a cold room, for +a time, where there is no fire, or where the temperature is moderate. + +716. When a person is found benumbed with cold, and almost or quite +insensible, he should be taken into a cold room, the clothing removed, +and friction commenced and continued for some time, with _snow_. When +warmth begins to be restored, the individual should be rubbed with dry +flannel, and the friction continued until reaction takes place. + +_Observation._ When the toes and heels have been repeatedly chilled, +there may be produced a disease called _chilblains_. This affection is +attended with tenderness of the parts, accompanied with a peculiar and +troublesome itching. The prevention of this disease is in wearing warm +hose and thick shoes of ample size. Bathing the feet morning and +evening is also a prevention of this disagreeable affection. When +chilblains exist, apply cold water, warm camphorated spirits, or +turpentine linament. + + -=-=-=-=-=-=-=-=-=-=-=-= + +715. How may the circulation and sensibility be restored? 716. What +treatment should be adopted when a person is benumbed with cold? What +treatment should be adopted when warmth begins to be restored? What is +said of chilblains? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXXV. + +APPENDAGES OF THE SKIN. + + +717. The HAIRS are appendages of the skin, and, like the cuticle, they +are a product of secretion. They have no blood-vessels or nerves, and, +consequently, no vitality. The hairs take their origin from the +cellular membrane, in the form of bulbs. Each hair is enclosed beneath +the surface by a vascular secretory follicle, which regulates its form +during growth. In texture, it is dense, and homogeneous toward the +circumference, and porous and cellular in the centre, like the pith of +a plant. Every hair has on its surface pointed barbs, arranged in a +spiral manner, and directed toward the root of the hair; so that, if a +hair be rolled between the fingers, it moves only in one direction. + +[Illustration: Fig. 118. The hair follicle (1) is represented as imbedded +in the cellular membrane, (2,) which is situated beneath the skin. 3, 3, +The membranous sac, which has a narrow neck, opening externally by a +contracted orifice, through which the hair (4) passes. Its internal +surface is smooth, and not adherent to the hair, but separated from it by +a reddish fluid. From the bottom of the sac (5) the pulp of the hair +arises, and passes through the skin at 6.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +717-723. _Describe the appendages of the skin._ 717. Why have not +hairs vitality? Where do they take their origin? Give their structure. +What is represented by fig. 118? + + -=-=-=-=-=-=-=-=-=-=-=-= + +718. The color of the hair varies in different individuals, and is +generally supposed to depend on the fluids contained in the pith. +There are two causes which act in changing the hair gray. The first +is, defective secretion of the coloring fluid. The second is, the +canals, which convey the fluid into the hair, become obliterated. In +the first instance, the hair will remain; in the second, it dies, and +drops out; the cuticle of the scalp grows over the canal, which is +soon obliterated, and the head becomes bald. + +_Observation._ It is related that the hair of Marie Antoinette, Queen +of France, and others, from excessive mental agitation, changed from +black to gray in a single night. This is not strictly true; the +secretion may be arrested, but that already deposited in the pith will +require days or weeks to be removed. + +719. Upon the upper part of the head, the oil-tubes open into the +hair-sacs; consequently, the secretion of the oil-glands is spread +over the surface of the hair, and not upon the cuticle. This is the +cause of the dry, white, branny scales, called "scurf," or "dandruff," +upon the head. This is natural, and cannot be prevented. When scurf +exists, the only necessary application to remove it, is the frequent +use of the hair-brush, and washing with pure water. + +_Observation._ The secretion of the oil-glands may become impacted +around the hairs as they issue from the skin, and thus prevent their +outward movement in growing. The pressure of the matter deposited at +their bulbs will then cause itching. The comb and the brush may be +used to remove the impacted matter, and relieve the disagreeable +sensation. + +720. The oil is most abundant near the roots of the hair A free use +of the brush spreads it along the hairs, and gives them a smooth, +glossy appearance. Soap should rarely be used in washing the head, as +it will remove the oil which is essential to the health and appearance +of the hair. + + -=-=-=-=-=-=-=-=-=-=-=-= + +718. Upon what does the color of the hair depend? What are the causes +of the hair becoming gray? What is the cause of the hair dropping out? +What is related of Marie Antoinette? 719. How is "dandruff" on the +scalp produced? What is the only necessary application to remove it? +Give observation. 720. Where is the oil of the hair most abundant? + + -=-=-=-=-=-=-=-=-=-=-=-= + +721. The uses of the hair vary in different regions of the body. Upon +the head, it aids in shielding the brain from injury by blows, and it +likewise serves to protect this part of the system from heat and cold, +thus maintaining equal temperature of the cerebral organ. About the +flections of the joints, as in the axilla, (armpit,) they prevent +irritation of the skin from friction; in the passages to the ears and +nostrils, they present an obstacle to the ingress of insects and +foreign bodies; while in the eyebrows and eyelids, they serve to +protect the organ of vision. + +[Illustration: Fig. 119. A section of the end of the finger and nail. 4, +Section of the last bone of the finger. 5, Fat, forming the cushion at +the end of the finger. 2, The nail. 1, 1, The cuticle continued under and +around the root of the nail, at 3, 3, 3.] + +722. The NAILS are hard, elastic, flexible, semi-transparent scales, +and present the appearance of a layer of horn. The nail is divided +into the _root_, the _body_, and the _free portion_. The root is that +part which is covered on both surfaces; the body is that portion which +has one surface free; the free portion projects beyond the end of the +finger. + +723. The nail is formed of several laminae, or plates, that are fitted +the one to the other; the deepest is that which is last formed. The +nails, as well as the hoofs of animals and the cuticle, are products +of secretion. They receive no blood-vessels or nerves. If the cuticle +be removed in severe scalds they will separate with it, as the hoofs +of animals are removed by the agency of hot water. The nails increase +in length and thickness, by the deposition of albumen upon their under +surface, and at their roots, in a manner similar to the growth of the +cuticle, of which they constitute a part. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How can it be spread along the hairs? Why should soap not be used in +washing the hair? 721. Of what use is the hair upon the head? About +the flexions of the joints? In the nasal and ear passages? Upon the +eyebrows and eyelids? 722. Describe the nails. 723. How are they +formed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observations._ 1st. The nail upon its under surface is fashioned into +thin vertical plates, which are received between the folds of the +sensitive skin. In this manner, the two kinds of laminae reciprocally +embrace each other, and the firmness of connection of the nail is +maintained. If we look on the surface of the nail, we see an +indication of this structure in the alternate red and white lines +which are there observed. The former of these correspond with the +sensitive laminae; the latter with the horny plates. The ribbed +appearance of the nail is due to the same circumstance. These +sensitive laminae are provided with an unusual number of capillary +vessels for the formation of the nail, and hence they give a red tint +to the portion under which they lie. + +2d. Near the root of the nail there is a part that is not laminated, +and it is less abundantly supplied with blood-vessels. This portion +consequently looks pale compared with the laminated portion, and from +its half-moon shape is technically termed _lunula_. Beyond the lunula, +the root of the nail is imbedded in the fold of the sensitive skin, +and has the same relation to that structure that any single one of the +thin horny plates of its under surface has to its corresponding pair +of sensitive laminae. + +724. The nails, from their position, are continually receiving +knocks, which produce a momentary disturbance of their cell +formation, followed by a white spot. The care of the nails should +be strictly limited to the knife or scissors, to their free border, +and an ivory presser, to prevent adhesion of the free margin of the +scarf-skin to the surface of the nail. This edge of the cuticle +should never be pared, the surface of the nail never scraped, nor the +nails cleaned with any instrument whatever, except the nail-brush, +aided by water and soap. An observance of these suggestions, will +prevent irregularities and disorders of the nails. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give observation 1st. Observation 2d. 724. How should the nails be +treated to prevent irregularities and disease? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observations._ 1st. When we wear a shoe that is too short for the +foot, the edge of the nail is brought against the leather. This +interrupts the forward growth of the nail, and it spreads out on the +sides, and becomes unusually thick. It then presses upon the soft +parts, and is said to "grow into the flesh." The prevention is, to +wear shoes of ample size. + +2d. Instances are by no means unfrequent in which the power of +production of the nail at the root becomes entirely destroyed, and it +then grows in thickness only. When this affection occurs, it is often +remarkable what a mass the nail presents. Instances are on record, +where the nail is regularly shed; and, whenever the old nail falls +off, a new one is found beneath it, perfectly formed. Sometimes the +growth in length is not entirely checked, although growth in thickness +is induced; the nail then presents a peculiar appearance. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What causes the edge of the nail "to grow into the flesh" of the toe? +How prevented? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXXVI. + +THE NERVOUS SYSTEM. + + +725. In the preceding chapters, we have seen how various and complex +are many of the motions necessary to maintain the life of an animal +whose organization is superior to all others. We have noted the +wonderful mechanism of the muscular system, in producing the varied +movements of the body, the different processes by which the food is +converted into chyle and mixed with the blood, and the circulation of +this fluid to every organ and tissue of the system, that each may +select from it the very principles which it requires for its growth. + +726. Lymphatic absorption commences as soon as nutrition is completed, +and conveys the useless, worn-out particles of different tissues back +into the circulating fluid; while the respiratory organs and secretory +glands perform the work of preparing the waste products to be +eliminated from the body. Each of these processes effects a single +object, and is performed in a regular manner. + +727. "They must succeed each other in proper order in propelling every +particle to its proper destination, or life would be sacrificed almost +at the moment of its commencement. There is, therefore, a mutual +dependence of all portions of the machinery of organic life upon each +other, and a necessity for some medium of communication from one organ +to another, by which they may convey mutual information of their +several conditions, if we may be permitted to employ a figurative +expression. Were there no such medium, how would the stomach notify +the heart that additional exertion on its part is required, because +the stomach is busy in digesting food? + + -=-=-=-=-=-=-=-=-=-=-=-= + +725. What has been noted in the preceding chapters? 726. Show the +manner in which the several processes are performed. 727. How must +they succeed each other? + + -=-=-=-=-=-=-=-=-=-=-=-= + +728. "When we are exerting the muscular system for a long time in some +laborious employment, how else are our members to inform the stomach +that they are too much occupied with their duties to spare the blood +necessary in digestion; that it is requisite that the appetite +should decline; and that digestion should cease for the time, even if +the stomach should be oppressed with its contents? When we are +thinking, how else are the blood-vessels to be told that an unusual +supply of their contents is wanting in the head? or when the whole +frame is weary with exertion, how, without some regular line of +intelligence between all the organs, is the brain to be instructed +that circumstances require that it should go to sleep? To supply the +necessary medium of communication, Providence has furnished all the +animals that possess distinct organs, with a peculiar apparatus +called the _Nervous System_." + + +ANATOMY OF THE NERVOUS SYSTEM. + +729. The NERVOUS SYSTEM consists of the _Cer'e-bro-spi'nal Cen'tre_, +and of numerous rounded and flattened white cords, called _nerves_, +which are connected at one extremity with the cerebro-spinal centre, +and at the other, distributed to all the textures of the body. The +sympathetic nerve is an exception to this description; for, instead of +one, it has many small centres, which are called _gan'gli-a_, and +which communicate very freely with the cerebro-spinal centre, and with +its nerves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +728. What is the medium of communication from one organ to another? +729-754. _Give the anatomy of the brain and cranial nerves._ 729. Of +what does the nervous system consist? What constitutes an exception to +this? + + -=-=-=-=-=-=-=-=-=-=-=-= + +730. The CEREBRO-SPINAL CENTRE consists of two portions: The _brain_, +and the _spinal cord_. For convenience of description, the nervous +system may be divided into the _Brain_, _Cranial Nerves_, _Spinal +Cord_, _Spinal Nerves_, and the _Sympathetic Nerve_. + +731. The term BRAIN designates those parts of the nervous system, +exclusive of the nerves themselves, which are contained within the +cranium, or skull-bones; they are the _Cer'e-brum_, _Cer-e-bel'lum_, +and _Me-dul'la Ob-lon-ga'ta_. These are invested and protected by the +membranes of the brain, which are called the _Du'ra Ma'ter_, +_A-rach'noid_, and _Pi'a Ma'ter_. + +[Illustration: Fig. 120. 1, 1, The scalp turned down. 2, 2, 2, The cut +edge of the bones of the skull. 3, The external strong membrane of the +brain (dura mater,) suspended by a hook. 4, The left hemisphere of the +brain, showing its convolutions.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +730. Of what does the cerebro-spinal centre consist? How is the +nervous system divided? 731. What does the term brain designate? Name +them. How are they protected? Describe fig. 120. + + -=-=-=-=-=-=-=-=-=-=-=-= + +732. The CEREBRUM IS divided into two hemispheres, by a cleft, or +fissure. Into this cleft dips a portion of the dura mater, called the +_falx cer'e-bri_, from its resembling a sickle. The apparent design of +this membrane is to relieve the one side from the pressure of the +other, when the head is reclining to either side. Upon the superior +surface of the cerebrum are seen undulating windings, called +_con-vo-lu'tions_. Upon its inferior, or lower surface, each +hemisphere admits of a division into three lobes--the anterior, +middle, and posterior. (Fig. 122, 123) + +[Illustration: Fig. 121 A section of the skull-bones and cerebrum. 1, 1, +The skull. 2, 2, the dura mater 3, 3, The cineritious portion of the +cerebrum. 4, 4, The medullary portion. The dark points indicate the +position of divided blood-vessels. 5, 5, The lateral ventricles.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +732. How is the cerebrum divided? What is the use of the falx cerebri? +What is seen upon the superior surface of the brain? Its inferior? + + -=-=-=-=-=-=-=-=-=-=-=-= + +733. When the upper part of the hemispheres is removed horizontally +with a sharp knife, a centre of white substance is brought to view. +This is surrounded by a border of gray, which follows the depressions +of the convolutions, and presents a zigzag outline. The divided +surface will be seen studded with numerous small red points, which are +produced by the escape of blood from the division of the minute +arteries and veins. The gray border is called the cortical, or +_cineritious_ portion, while the white central portion is called the +_medullary_. The two hemispheres are connected by a dense layer of +transverse fibres, called _cor'pus cal-lo'sum_. + +734. In the interior of the brain there are several cavities, two of +which are of considerable size, and are called the lateral ventricles. +They extend from the anterior to the posterior part of the brain, and +wind their way into other parts of the cerebral organ. + +_Observation._ In the disease called "dropsy of the brain," +(hydrocephalus internus,) the serum, or water, is usually deposited in +these ventricles. This is effused from the many small blood-vessels of +the membrane in these cavities. + +735. The brain is of a pulpy character, quite soft in infancy and +childhood; but it gradually becomes more and more consistent, and in +middle age it assumes the form of determinate structure and +arrangement. It is more abundantly supplied with blood than any organ +of the system. No lymphatics have been detected, but it is to be +presumed that they exist in this organ. + +736. The CEREBELLUM is about seven times smaller than the cerebrum. +Like that organ, it is composed of white and gray matter, but the +gray constitutes the larger portion. Its surface is formed of parallel +plates separated by fissures. The white matter is so arranged, that +when cut vertically, the appearance of the trunk and branches of a +tree (_ar'bor vi'tae_) is presented. It is situated under the posterior +lobe of the cerebrum, from which it is separated by a process of the +dura mater, called the _ten-to'ri-um_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +733. Describe the appearance of the brain when a horizontal section +has been made. What is the gray border often called? What connects the +hemispheres? 734. Describe the ventricles of the brain. In the disease +called "dropsy of the brain," where is the water deposited? 735. What +is the character of the brain in childhood? In adults? 736. How does +the cerebellum compare in size with the cerebrum? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 122. The under surface, or base, of the brain and +origin of the cranial nerves. 1, 1, The anterior lobes of the cerebrum. +2, 2, The middle lobes. 3, 3, The posterior lobes, almost concealed by +the cerebellum. 4, 4, The cerebellum. 7, 7, The longitudinal fissure that +divides the brain into two hemispheres. 8, The first pair of nerves. 9, +9, The second pair of nerves. 10, The decussation, or crossing, of its +fibres. 13, 13, The third pair of nerves. 14, The pons varolii. 15, 15, +The fourth pair of nerves. 16, 16, The fifth pair of nerves. 17, The +sixth pair of nerves. 18, 18, The seventh and eighth pair of nerves. 19, +The medulla oblongata, with the crossing of some of its fibres exhibited. +20, The ninth pair of nerves. 21, The tenth pair of nerves, 22, The +eleventh pair of nerves. 23, The twelfth pair of nerves.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +Describe this portion of the brain. Explain fig. 122. + + -=-=-=-=-=-=-=-=-=-=-=-= + +737. The MEDULLA OBLONGATA, or that portion of the spinal cord which +is within the skull, consists of three pairs of bodies, (_cor'pus +py-ram-i-da'le_, _res-ti-for'me_, and _ol-i-va're_,) united in a +single bulb. + +[Illustration: Fig. 123. The base of the skull and the openings through +which the cranial nerves pass. 1, 1, The first pair of nerves. 2, 2, The +cribriform plate of the ethmoid bone through which this nerve passes. 3, +3, The second pair of nerves. 4, 4, The optic foramen in the sphenoid +bone; through which passes the second pair of nerves. 5, 5, The +sphenoidal fissure. 6, 6, The third pair of nerves. 7, 7, The fifth pair +of nerves. 8, 8, The ophthalmic branch of the fifth nerve. The third, the +ophthalmic branch of the fifth and the sixth nerve pass from the brain +through the sphenoidal fissure to the eye. 9, 9, The superior maxillary +branch of the fifth nerve. 10, 10, The foramen rotundum, (round opening,) +through which the nerve 9, 9, passes to the upper jaw. 11, 11, The +inferior maxillary branch of the fifth pair. 12, 12, The foramen ovale, +(oval opening,) through which the nerve 11, 11, passes to the lower jaw. +13, 13, The sixth pair of nerves. 14, 14, The seventh and eighth pair of +nerves. 15, 15, The opening in the temporal bone, through which the +seventh and eighth nerves pass to the face and ear. 16, 16, The ninth +pair of nerves. 17, The tenth pair of nerves. 18, 18, The eleventh pair +of nerves. 19, 19, The foramen lacerum (rough opening.) The ninth, tenth, +and eleventh nerves pass from the brain through this opening. 20, The +spinal cord. 21, The foramen spinalis, through which the spinal cord +passes. 22, 22, The position of the anterior lobe of the brain. 23, 23, +The middle lobe. 24, 24, The posterior lobe. 25, 25, A section of the +skull-bones.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +737. Describe the medulla oblongata. Explain fig. 123. + + -=-=-=-=-=-=-=-=-=-=-=-= + +738. The DURA MATER is a firm, fibrous membrane, which is exposed on +the removal of a section of the skull-bones. This lines the interior +of the skull and spinal column, and likewise sends processes inward, +for the support and protection of the different parts of the brain. It +also sends processes externally, which form the sheaths for the +nerves, as they quit the skull and spinal column. The dura mater is +supplied with arteries and nerves. + +[Illustration: Fig. 124. A vertical section of the cerebrum, cerebellum, +and medulla oblongata, showing the relation of the cranial nerves at +their origin. 1, The cerebrum. 2, The cerebellum, with its arbor vitae +represented. 3, The medulla oblongata. 4, The spinal cord. 5, The corpus +callosum. 6, The first pair of nerves. 7, The second pair. 8, The eye. 9, +The third pair of nerves. 10, The fourth pair. 11, The fifth pair. 12, +The sixth pair. 13, The seventh pair. 14, The eighth pair. 15, The ninth +pair. 16, The tenth pair. 10, The eleventh pair. 18, The twelfth pair. +20, Spinal nerves. 21, The tentorium.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +738. Describe the dura mater. What is its use? Explain fig. 124. + + -=-=-=-=-=-=-=-=-=-=-=-= + +739. The ARACHNOID, so called from its extreme tenuity, is the serous +membrane of the brain and spinal cord, and is, like other serous +membranes, a closed sac. It envelops these organs, and is reflected +upon the inner surface of the dura mater, giving to that membrane its +serous investment. + +740. The PIA MATER is a vascular membrane, composed of innumerable +vessels, held together by cellular membrane. It invests the whole +surface of the brain, and dips into its convolutions. The pia mater is +the nutrient membrane of the brain, and receives its blood from the +carotid and vertebral arteries. Its nerves are minute branches of the +sympathetic, which accompany the branches of the arteries. + +741. The CRANIAL NERVES, that connect with the brain, are arranged in +twelve pairs. They are called: 1st. The _Ol-fact'o-ry_. 2d. The +_Op'tic_. 3d. The _Mo-to'res Oc-u-lo'rum_. 4th. The _Pa-thet'i-cus_. +5th. The _Tri-fa'cial_. 6th. The _Ab-du-cen'tes_. 7th. The _Por'ti-o +Du'ra_. 8th. The _Por'ti-o Mol'lis_. 9th. The _Glos'so-pha-ryn'gi-al_. +10th. The _Pneu-mo-gas'tric_. 11th. The _Spi'nal Ac'ces-so-ry_. 12th. +The _Hy'po-glos'sal_. + +742. The OLFACTORY NERVE (first pair) passes from the cavity of the +skull through many small openings in a plate of the _eth'moid_ bone. +(This plate is called _crib'ri-form_, from its resemblance to a +sieve.) This nerve ramifies upon the membrane that lines the nasal +passages. It is the softest nerve of the body. (Fig. 136.) + +743. The OPTIC NERVE (second pair) passes from the interior of the +cranium, through an opening in the base of the skull, (_fo-ra'men +op'ti-cum_,) to the cavity for the eye. It pierces the coats of the +eye, and expands in the retina. + +744. The MOTORES OCULORUM (third pair) pass from the brain, through +an opening of the _sphe'noid_ bone, (_sphe-noid'al fis'sure_,) to the +muscles of the eye. + + -=-=-=-=-=-=-=-=-=-=-=-= + +739. Describe the arachnoid membrane. 740. What is said respecting the +pia mater? 741. How many pairs of cranial nerves? Name them. 742. +Describe the olfactory nerve. 743. The optic nerve. 744. Describe the +motores oculorum. + + -=-=-=-=-=-=-=-=-=-=-=-= + +745. The PATHETICUS (fourth pair) passes from the brain, through the +sphenoidal fissure, to the superior oblique muscle of the eye. + +[Illustration: Fig. 125. The distribution of the third, fourth, and sixth +pairs of nerves, to the muscles of the eye. 1, The ball of the eye and +rectus externus muscle. 2, The upper jaw. 3, The third pair, distributed +to all the muscles of the eye, except the superior oblique, and external +rectus. 4, The fourth pair passes to the superior oblique muscle. 6, The +sixth pair, is distributed to the external rectus muscle.] + +746. The TRIFACIAL NERVE (fifth pair) is analogous to the spinal +nerves in its origin by two roots, from the anterior and posterior +columns of the spinal cord. It has a ganglion, like the spinal nerves +upon its posterior root. For these reasons, it ranges with the spinal +nerves, and is considered the cranial spinal nerve. This nerve divides +into three branches:--The _oph-thal'mic_, superior _max'il-la-ry_, and +inferior _max'il-la-ry_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +745. The patheticus. What does fig. 125 represent? 746. What is the +trifacial nerve sometimes called? Why is it classed with the cranial +spinal nerves? Give the names of its branches. + + -=-=-=-=-=-=-=-=-=-=-=-= + +747. The ophthalmic nerve passes from the cranial cavity through the +sphenoidal fissure. It sends branches to the forehead, eye, and nose. +The superior maxillary nerve passes through an opening in the base of +the skull, (_foramen ro-tund'dum_,) and sends branches to the eye, the +teeth of the upper jaw, and the muscles of the face. The inferior +maxillary nerve escapes from the cranial cavity through an opening +called _foramen o-va'le_. It sends branches to the muscles of the +lower jaw, the ear, the tongue, and the teeth of the lower jaw. + +[Illustration: Fig. 126. The distribution of the fifth pair of nerves. 1, +The orbit for the eye. 2, The upper jaw. 3, The tongue. 4, The lower jaw. +5, The fifth pair of nerves. 6, The first branch of this nerve, that +passes to the eye. 9, 10, 11, 12, 13, 14, Divisions of this branch. 7, +The second branch of the fifth pair of nerves is distributed to the teeth +of the upper jaw. 15, 16, 17, 18, 19, 20, Divisions of this branch. 8, +The third branch of the fifth pair, that passes to the tongue and teeth +of the lower jaw. 23. The division of this branch that passes to the +tongue, called the _gust'a-to-ry_. 24. The division that is distributed +to the teeth of the lower jaw.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +747. Where do the filaments of the ophthalmic branch ramify? The +superior maxillary? The inferior maxillary? Explain fig. 126. + + -=-=-=-=-=-=-=-=-=-=-=-= + +748. The ABDUCENTES (sixth pair) passes through the opening by which +the carotid artery enters the cranial cavity. It is the smallest of +the cerebral nerves, and is appropriated to the external straight +muscle of the eye. + +749. The PORTIO MOLLIS (seventh pair) enters the hard portion of the +_tem'po-ral_ bone at the internal auditory opening, and is distributed +upon the internal ear. (Fig. 147, 148.) + +[Illustration: Fig. 127. A representation of the distribution of the +eighth pair of nerves with some branches of the fifth. 1, 2, 3, 5, 7, 9, +Are branches of the eighth pair. They are distributed over the face in a +radiated manner, which constitutes the pes anserinus, (foot of a goose.) +The nerves 4, 6, 8, are branches of the fifth pair. 10, 11, 12, 13, 14, +15, 16, Are branches of nerves from the upper part of the spinal cord, +(cervical.)] + +750. The FACIAL NERVE (eighth pair) passes from the skull through an +opening situated below the ear, (_mas'toid foramen_.) It is +distributed over the face, supplying the muscles with nervous +filaments. + + -=-=-=-=-=-=-=-=-=-=-=-= + +748. What is said of the abducentes, or sixth pair of nerves? 749. Of +the portio mollis? Explain fig. 127. 750. Of the facial nerve? + + -=-=-=-=-=-=-=-=-=-=-=-= + +751. The GLOSSO-PHARYNGEAL NERVE (ninth pair) passes from the brain, +through an opening with the jugular vein, (_foramen lac'e-rum_.) It is +distributed to the mucous membrane of the tongue and throat, and also +to the mucous glands of the mouth. + +752. the PNEUMOGASTRIC NERVE (tenth pair) escapes from the brain +through the foramen lacerum. It sends branches to the larynx, pharynx, +oesophagus, lungs, spleen, pancreas, liver, stomach, and intestines. +(Fig. 132.) + +753. The SPINAL ACCESSORY NERVE (eleventh pair) has its origin in the +respiratory tract of the spinal cord. It connects with the ninth and +tenth pairs of nerves, and is distributed to the muscles about the +neck. + +754. The HYPO-GLOSSAL NERVE (twelfth pair) passes from the brain, +through a small opening, (_con'dy-loid foramen_.) It ramifies upon the +muscles of the tongue, and is its motor nerve. + +_Observation._ The cranial nerves, with the exception of the +olfactory, optic, and auditory, connect with each other by means of +filaments. They also send connecting nervous filaments to the upper +spinal nerves, (cervical,) and the sympathetic nerve. + + -=-=-=-=-=-=-=-=-=-=-=-= + +751. Describe the glosso-pharyngeal nerve. 752. The pneumogastric +nerve. 753. The spinal accessory nerve. 754. The hypo-glossal nerve. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXXVII. + +ANATOMY OF THE NERVOUS SYSTEM, CONTINUED. + + +755. The spinal column contains the spinal cord, the roots of the +spinal nerves, and the membranes of the cord. + +756. The SPINAL CORD extends from the medulla oblongata to the second +lumbar vertebra, where it terminates in a rounded point. It presents a +difference of diameter in different parts of its extent, and exhibits +three enlargements. The uppermost of these is the medulla oblongata. +There is no distinct demarkation between this enlargement and the +spinal cord. The next corresponds with the origin of the nerves +distributed to the upper extremities; the third enlargement is +situated near the termination of the cord, and corresponds with the +attachment of the nerves which are intended for the supply of the +lower extremities. + +757. An anterior and posterior fissure divides the spinal cord into +two lateral cords. These are united by a thin layer of white +substance. The lateral cords are each divided by furrows into three +distinct sets of fibres, or columns; namely the _anterior_, _lateral_, +and _posterior_ columns. The anterior are the motor columns; the +posterior are the columns of sensation; the lateral columns are +divided in their function between motion and sensation. They contain +the fasciculus described, by Sir Charles Bell, as the respiratory +tract. + +[Illustration: Fig. 128. A section of the brain and spinal column. 1, The +cerebrum. 2, The cerebellum. 3, The medulla oblongata. 4, 4, The spinal +cord in its canal.] + +[Illustration: Fig. 129. Anterior view of the brain and spinal cord. 1, +1, The two hemispheres of the cerebrum. 3, 3, The cerebellum. 4, The +olfactory nerve. 5, The optic nerve. 7, The third pair of nerves. 8, The +pons varolii. 9, The fourth pair of nerves. 10, The lower portion of the +medulla oblongata. 11, 11, The spinal cord. 12, 12, Spinal nerves. 13, +13, The brachial plexus. 14, 14, The lumbar and sacral plexus.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +755-767. _Give the anatomy of the spinal cord, spinal nerves, and the +sympathetic nerve._ 755. What does the spinal column contain? 756. +Give the extent of the spinal cord. How many enlargements has this +cord? What is said of each enlargement? 757. Into how many parts is +the spinal cord divided? Give the function of these columns. + + -=-=-=-=-=-=-=-=-=-=-=-= + +758. The SPINAL NERVES, that connect with the spinal cord, are +arranged in thirty-one pairs, each arising by two roots; an anterior, +or _motor_ root, and a posterior, or _sensitive_ root. Each nerve, +when minutely examined, is found to consist of an aggregate of very +delicate filaments, enclosed in a common cellular envelope. + + -=-=-=-=-=-=-=-=-=-=-=-= + +758. How many pairs of nerves issue from the spinal cord? Explain fig. +128. Fig. 129. + + -=-=-=-=-=-=-=-=-=-=-=-= + +759. The anterior roots arise from a narrow white line upon the +anterior columns of the spinal cord. The posterior roots arise from a +narrow gray band formed by the internal gray substance of the cord. +They are larger, and the filaments of origin more numerous than those +of the anterior roots. A ganglion is found upon each of the posterior +roots in the openings between the bones of the spinal column through +which the nerve passes. + +[Illustration: Fig. 130. A section of the spinal cord, surrounded by its +sheath. B, A spinal nerve, formed by the union of the motor root (C) and +the sensitive root (D.) At D, the ganglion upon this root is seen.] + +760. After the formation of the ganglion, the two roots unite, and +constitute a spinal nerve, which passes through the opening between +the vertebrae on the sides of the spinal column. The nerves divide and +subdivide, until their minute filaments ramify on the tissues of the +different organs. + + -=-=-=-=-=-=-=-=-=-=-=-= + +759. Give the origin of the anterior roots. Of the posterior roots. In +what respect do the posterior roots differ from the anterior? 760. +When do the two roots unite, and where do they pass? + + -=-=-=-=-=-=-=-=-=-=-=-= + +761. The _spinal nerves_ are divided into-- + + Cervical, 8 pairs, + Dorsal, 12 " + Lumbar, 5 " + Sacral, 6 " + +762. The four lower cervical and upper dorsal pass into each other and +then separate to reunite. This is called the _brach'i-al plex'us_. +From this plexus six nerves proceed, which ramify upon the muscles and +skin of the upper extremities. + +763. The last dorsal and the five lumbar nerves form a plexus called +the lumbar, similar to that of the cervical. Six nerves pass from this +plexus, which ramify upon the muscles and skin of the lower +extremities. + +764. The last lumbar and the four upper sacral unite to form the +sacral plexus. From this plexus five nerves proceed, that are +distributed to the muscles and skin of the hip and lower extremities. + +765. The SYMPATHETIC NERVE[19] consists of a series of _Gan'gli-a_, or +knots, extending each side of the spinal column, forming a chain its +whole length. It communicates with both the cranial and spinal nerves. +With the exception of the neck, there is a ganglion for each +intervertebral space. These ganglia are composed of a mixture of +cineritious and medullary matter, and are supposed to be productive of +peculiar nervous power. + + [19] The structure of this nerve is very complicated, and different + physiologists ascribe to it various functions. The character of + its diseases are not well understood. + + -=-=-=-=-=-=-=-=-=-=-=-= + +761. Give the division of the spinal nerves. 762. What nerves +constitute the brachial plexus? How many nerves pass from this plexus? +763. How many nerves from the lumbar plexus, and where do they ramify? +764. How is the sacral plexus formed? 765. Of what does the +sympathetic nerve consist? How is the sympathetic nerve distributed? +What exception? Of what are the ganglia composed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 131. A beautiful representation of the sympathetic +ganglia and their connection with other nerves. It is from the grand +engraving of Manec, reduced in size. A, A, A, The semilunar ganglion and +solar plexus, situated below the diaphragm and behind the stomach. This +ganglion is situated in the region (pit of the stomach) where a blow +gives severe suffering. D, D, D, The thoracic ganglia, ten or eleven in +number. E, E, The external and internal branches of the thoracic ganglia. +G, H, The right and left coronary plexus, situated upon the heart. I, N, +Q, The inferior, middle, and superior cervical ganglia. 1, The renal +plexus of nerves that surrounds the kidneys. 2, The lumbar ganglion. 3, +Their internal branches. 4, Their external branches. 5, The aortic plexus +of nerves that lies upon the aorta. The other letters and figures +represent nerves that connect important organs and nerves with the +sympathetic ganglia.] + +766. The GANGLIA may be considered as distinct centres, giving off +branches in four directions; namely, the superior, or ascending, to +communicate with the ganglion above; the inferior, or descending, to +communicate with the ganglion below; the external, to communicate with +the spinal nerves; and the internal, to communicate with the +sympathetic filaments. It is generally admitted that the nerves that +pass from the ganglia are larger than those that entered them; as if +they imparted to the nerve some additional power. + +767. The branches of distribution accompany the arteries which supply +the different organs, and form communications around them, which are +called plexuses, and take the name of the artery with which they are +associated. Thus we have the mesenteric plexus, hepatic plexus, +splenic plexus, &c. All the internal organs of the head, neck, and +trunk, are supplied with branches from the sympathetic, and some of +them exclusively; for this reason, it is considered a nerve of organic +life. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is the design of fig, 131? 766. How may the ganglia be +considered? 767. What is said of the branches of the sympathetic +nerve? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XXXVIII. + +PHYSIOLOGY OF THE NERVOUS SYSTEM. + + +768. The brain is regarded by physiologists and philosophers as the +organ of the mind. Most writers consider it as an aggregate of parts, +each charged with specific functions, and that these functions are the +highest and most important in the animal economy. To the large brain, +or cerebral lobes, they ascribe the seat of the faculties of +_thinking_, _memory_, and _the will_. In man, this lobe extends so far +backward as to cover the whole of the cerebellum. To the cerebellum, +or little brain, is ascribed the seat of the _animal_, or _lower +propensities_. + +769. "The constant relation between mental power and development of +brain, explains why capacities and dispositions are so different. In +infancy, for example, the intellectual powers are feeble and inactive. +This arises partly from the inaptitude of a still imperfect brain; but +in proportion as the latter advances toward its mature state, the +mental faculties also become vigorous and active." + +770. We are able, in most instances, at least, to trace a correspondence +between the development of the cerebral lobes and the amount of +intelligence possessed by the person. The weight of the brain in man +to that of the whole body varies in different individuals. The +heaviest brain on record was that of Cuvier, which weighed 4 pounds +and 13 1/2 ounces. + + -=-=-=-=-=-=-=-=-=-=-=-= + +768-772. _Give the physiology of the nervous system._ 768. How is the +brain regarded by physiologists and philosophers? What do they ascribe +to the cerebrum? To the cerebellum? 769. What does the relation +between mental powers and development of brain explain? 770. What is +said respecting the correspondence between the development of the +brain and the amount of intelligence possessed by the person? What is +said of the weight of the brain? + + -=-=-=-=-=-=-=-=-=-=-=-= + +771. The brain likewise holds an important relation to all the other +organs of the system. To the muscular system it imparts an influence +which induces contraction of the fibres. By this relation they are +brought under the control of the will. To the skin, eye, and ear, it +imparts an influence that gives sensibility, or the power of feeling, +seeing, hearing, &c. + +772. Again, the involuntary functions of the different portions of the +system are more or less influenced by the brain. If the action of this +central organ of the nervous system is destroyed, the functions of the +digestive, respiratory, and circulatory apparatuses will be much +disturbed or entirely suppressed. + +773. The brain is the seat of _sensation_. It receives the impressions +made on all parts of the body, through the medium of the sensitive +nerves. That the impressions of external objects, made on these +nerves, be communicated to the brain, where sensation is perceived, it +is necessary that they be not diseased or injured. + +_Observation._ There is a plain distinction between sensations and +impressions; the latter are the changes produced in the extremities of +the nerve; the former, the changes produced in the brain and +communicated to the mind. + +774. What part of the brain receives the impressions or has the most +intimate relation with the intellectual faculties is unknown. Some +portions, however, are of less importance than others. Large portions +of the cortical, or outer part, are frequently removed without +affecting the functions of this organ. Pieces of the medullary, or +central parts, have been removed by injuries without impairing the +intellect or destroying life. This organ, although it takes cognizance +of every sensation, is, of itself, but slightly sensible. It may be +cut, or parts may be removed without pain, and the individual, at the +same times retain his consciousness. + + -=-=-=-=-=-=-=-=-=-=-=-= + +771. What is said of the relation of the brain to all of the organs of +the body? 772. Are the involuntary functions of different parts of the +system influenced by the brain? 773. Where is sensation perceived? By +what agency are the impressions of external objects conveyed to the +brain? What is the difference between sensations and impressions? 774. +Is it known what part of the brain has the most intimate relation with +the intellectual faculties? + + -=-=-=-=-=-=-=-=-=-=-=-= + +775. The brain is the seat of the _will_. It superintends the physical +as well as the mental movements, and the medium of communication from +this organ to the muscles, or the parts to be moved, is the motor +nerves. If the brain is in a quiescent state, the muscles are at rest; +if, by an act of the will, the brain sends a portion of nervous +influence to a voluntary muscle, it immediately contracts, and those +parts to which the muscle is attached move. There is no perceptible +interval between the act of the will and the motion of the part. + +776. Some physiologists assert, that the medulla oblongata is the +point at which excitement to motion commences, and sensation +terminates; and also, that it possesses the power of originating +motion in itself. + +_Observation._ The medulla oblongata, unlike the brain, is highly +sensitive; if slightly punctured, convulsions follow; if much injured, +respiration, or breathing, immediately ceases. + +777. It is remarkable that the nerves which arise from the right side +of the spinal cord communicate with the left hemisphere of the +cerebrum, and _vice versa_; this results from the crossing of the +fibres in the medulla oblongata. It follows from this, that if the +right side of the brain receives an injury, the parts of the opposite +side of the body lose their sensibility and motion. + +_Observations._ 1st. If the cranial nerves which are connected by a +single root are divided, only the sensation of the part to which they +are distributed is lost. Thus, if the optic nerve is divided, the +sense of vision disappears, but the motions of the eye are performed +as readily as before. But, if the spinal nerves are divided, both +sensation and motion of the part to which they lead are destroyed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What portions have been removed without impairing the intellect? What +is remarkable of the brain? 775. What is the influence of the brain +upon the muscles? 776. What do some physiologists assert of the +medulla oblongata? 777. What is remarkable of the nerves? Give the 1st +observation relative to the cranial nerves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. When the spinal cord is divided or compressed, as in fractures of +the spinal column, all parts below the fracture are paralyzed, though +the nerves leading to these parts may be uninjured. + +3d. Again, one side of the body or one limb may become insensible, and +the power to move it, be perfectly retained; or the reverse of this +may happen--the power of motion will be lost while sensation remains. +In the former instance, the function of the posterior, or sensitive +column of the spinal cord on one side is destroyed; in the latter, the +anterior, or motor column is affected. + +4th. In some cases, both sensation and motion of one side of the body +or one limb are destroyed. In such instances, both the anterior and +the posterior columns of one side of the spinal cord are diseased. + +778. Vigorous and controllable muscular contraction requires a sound +and well-developed brain. If this organ is defective in these +particulars, the movements will be inefficient, and may be irregular. +The central organ of the nervous system must, likewise, be in an +active condition, to induce regular, steady, and controllable muscular +movements. + +_Observations._ 1st. Persons who have suffered from apoplexy and other +severe diseases of the brain, have an involuntary trembling of the +limbs, which results from a weakened state of the nervous system. + + -=-=-=-=-=-=-=-=-=-=-=-= + +To the spinal nerves. What is said of the compression of the spinal +cord? Give the 3d observation relative to the spinal nerves. The 4th +observation. 778. Upon what does vigorous controllable muscular +contraction depend? What causes the involuntary trembling of the limbs +in persons who have suffered from apoplexy? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. The tremor of the hand, that lessens the usefulness or incapacitates +the fine artist or skilful mechanic, in the prime of life, from +pursuing their vocations, may be, and is often, induced by the +influence of intoxicating drink, which debilitates and disorganizes the +brain. + +3d. The tottering step, trembling hand, and shaking head of the aged +invalid, are the results of diminished nervous energy, so that steady +muscular contraction, so essential to regular movements, cannot be +maintained. + +779. No difference can be discovered in the structure of the several +kinds of nerves in any part of their course, and the functions they +are designed to perform can only be known by ascertaining the place of +their origin. The nerves may be functionally divided into five +groups. + +780. 1st. _Nerves of special sensation._ These are the first, second, +eighth, and it may be one of the branches of the fifth pair of cranial +nerves. The function of these nerves is particularly described in the +chapters upon the senses of smell, vision, hearing, and taste. + +781. 2d. _Nerves of general sensation._ These embrace the fifth pair +of cranial nerves, and the thirty-one pairs of spinal nerves. In those +parts that require sensation for their safety and the performance of +their functions, there is an abundant supply of sensitive nervous +filaments. The nerves of sensation are mostly distributed upon the +skin. Few filaments ramify upon the mucous membranes and muscles. + +_Observations._ 1st. The painful sensations experienced in the face, +and in the teeth or jaws, (tic douloureux and toothache,) are induced +by irritation and disease of a portion of the filaments of the fifth +pair of cranial nerves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +The tremor of the hand among some mechanics in the prime of life? The +tottering step of the aged invalid? 779. What is said relative to the +structure of the nerves? How may they be divided? 780. Give the nerves +of special sense. 781. Those of general sensation. Where are the +nerves of sensation distributed? What causes tic douloureux? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. The unpleasant sensation sometimes experienced when we hear the +grating of a file or saw, is produced by the connection of the nerve +that passes across the drum of the ear with the fifth cranial nerve. + +3d. When pressure is made on the trunk of a nerve, the sensibility of +the part where the nerve ramifies is modified. This is illustrated, +when pressure is made upon the large nerve of the lower extremity +(sciatic) in sitting upon a hard bench. The foot is then said to be +"asleep." + +4th. When the trunk of a nerve is diseased or injured, the pain is +experienced in the outer extremity of the nerve. A blow upon the +elbow, which causes a peculiar sensation in the little finger and one +side of the ring finger, affords a familiar illustration. This +sensation is produced by injuring the ulnar nerve, which is +distributed to the little finger. + +782. 3d. _Nerves of motion._ These are the third, sixth, and twelfth +pairs of cranial nerves, and the thirty-one pairs of spinal nerves. +These nerves are distributed to the fibres of the five hundred muscles +of the body. The functions of the muscular are different from those of +the sensitive nerves. The former are provided for the purpose of +motion, and not of feeling. Hence, muscles may be cut, and the pain +will be slight, compared with the cutting of the skin. This may be +called muscular pain. Weariness is a sensation recognized by one set +of muscular nerves. + +783. So uniformly is a separate instrument provided for every +additional function, that there is strong reason to regard the +muscular nerves, although running in one sheath, as in reality double, +and performing distinct functions. Sir Charles Bell, in his work on +the Nervous System, endeavors to show, that one set of nervous fibres +conveys the mandate from the brain to the muscle, and excites the +contraction; and that another set conveys, from the muscle to the +brain, a peculiar sense of the state or degree of contraction of the +muscle, by which we are enabled to judge of the amount of stimulus +necessary to accomplish the end desired. This is obviously an +indispensable piece of information to the mind in regulating the +movements of the body. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is the peculiar sensation accounted for when we hear the grating +of a file or saw? What produces the sensation when the foot is said to +be "asleep?" What is the effect when the ulnar nerve is injured by a +blow? 782. Give the nerves of motion. What is said of the functions of +the muscular nerves? 783. What does Sir Charles Bell endeavor to +show? + + -=-=-=-=-=-=-=-=-=-=-=-= + +784. 4th. _Nerves of respiration._ These are the fourth, seventh, +ninth, tenth, and eleventh pair of cranial nerves, also the phrenic +and the external respiratory nerve. All of these nerves have their +origin in a distinct tract or column, called the lateral, in the upper +part of the spinal cord. Hence it is sometimes named the respiratory +column. These nerves are distributed to one of the muscles of the eye; +to the muscles of the face; to the tongue, pharynx, oesophagus, +stomach, heart, lungs, diaphragm, and some of the muscles of the neck +and chest. + +785. It is through the instrumentality of the accessory, phrenic, +and external respiratory nerves, (10, 11, 12, 13, fig. 132,) that +the muscles employed in respiration are brought into action without +the necessity of the interference of the mind. Though to a certain +extent they may be under the influence of the will, yet it is only in +a secondary degree. No one can long suspend the movements of +respiration;[20] for in a short time, instinctive feeling issues +its irresistible mandate, which neither requires the aid of erring +wisdom, nor brooks the capricious interference of the will. + + [20] Dr. Elliotson, and some other writers On physiology, have + detailed cases of death from voluntary suspension of respiration. + But these cases are not conclusive, as examinations were not + made, so as to determine positively, that death did not result + from disease of the heart, brain, or some other vital organ. + +[Illustration: Fig. 132. The distribution of the respiratory nerves. _a_, +Section of the brain and medulla oblongata. _b_, The lateral columns of +the spinal cord. _c_, _c_, The respiratory tract of the spinal cord. _d_, +The tongue. _e_, The larynx. _f_, The bronchia. _g_, The oesophagus. _h_, +The stomach. _i_, The diaphragm. 1, The pneumogastric nerve. 2, The +superior laryngeal nerve. 3, The recurrent laryngeal nerve. (These two +ramify on the larynx.) 4, The pulmonary plexus of the tenth nerve. 5, The +cardiac plexus of the tenth nerve. These two plexuses supply the heart +and lungs with nervous filaments. 7, The origin of the fourth pair of +nerves, that passes to the superior oblique muscle of the eye. 8, The +origin of the facial nerve, that is spread out on the side of the face +and nose. 9, The origin of the glosso-pharyngeal nerve, that passes to +the tongue and pharynx. 10, The origin of the spinal accessory nerve. 11, +This nerve penetrating the sterno-mastoideus muscle. 12, The origin of +the internal respiratory or phrenic nerve, that is seen to ramify on the +diaphragm. 13, The origin of the external respiratory nerve, that +ramifies on the pectoral and scaleni muscles.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +784. Give the respiratory nerves. What is said in reference to the +respiratory nerves? 785. Through the agency of what nerves are the +respiratory muscles brought into action? Explain fig. 132. + + -=-=-=-=-=-=-=-=-=-=-=-= + +786. The fourth, seventh, and tenth pairs of nerves, (7, 8, 9, fig. +132,) with the spinal accessory, phrenic, and external respiratory, +are not only connected with the function of respiration, but +contribute to the expression of the passions and emotions of the +mind. + +787. The influence of this order of nerves in the expression of the +passions, is strikingly depicted in Sir Charles Bell's Treatise on the +Nervous System. "In terror," he remarks, "we can readily conceive why +a man stands with his eyes intently fixed on the object of his +fears--the eyebrows elevated, and the eyeballs largely uncovered; or +why, with hesitating and bewildered steps, his eyes are rapidly and +wildly in search of something. In this way, we only perceive the +intense application of his mind to the objects of his apprehension, +and its direct influence on the outward organs." + + -=-=-=-=-=-=-=-=-=-=-=-= + +Can respiration be suspended for any considerable length of time? 786. +What nerves contribute to the expression of the passions and emotions +of the mind? 787, 788. What does Sir Charles Bell say of the influence +of this order of nerves in the expression of the passions? + + -=-=-=-=-=-=-=-=-=-=-=-= + +788. "But when we observe him further, there is a spasm in his breast; +he cannot breathe freely; the chest remains elevated, and his +respiration is short and rapid. There is a gasping and convulsive +motion of his lips, a tremor on his hollow cheeks, a gasping and +catching of his throat; his heart knocks at his ribs, while yet there +is no force in the circulation--the lips and cheeks being ashy pale." + +789. "These nerves are the instruments of expression, from the smile +upon the infant's cheek, to the last agony of life. It is when the +strong man is subdued by this mysterious influence of soul on body, +and when the passions may be truly said to tear the heart, that we +have the most afflicting picture of human frailty, and the most +unequivocal proof that it is the order of functions we have been +considering, that is thus affected. In the first struggle of the +infant to draw breath, in the man recovering from a state of +suffocation, and in the agony of passion, when the breast labors from +the influence at the heart, the same system of parts is affected, the +same nerves, the same muscles, and the symptoms or character have a +strict resemblance." + +790. The seventh pair of nerves not only communicates the purposes of +the will to the muscles of the face, but at the same time it calls +them into action, under the influence of instinct and sympathy. On +this subject a late writer remarks, "How expressive is the face of +man! How clearly it announces the thoughts and sentiments of the mind! +How well depicted are the passions on his countenance! tumultuous +rage, abject fear, devoted love, envy, hatred, grief, and every other +emotion, in all their shades and diversities, are imprinted there, in +characters so clear that he that runs may read! How difficult, nay, +how impossible, is it to hide or falsify the expressions which +indicate the internal feelings! Thus conscious guilt shrinks from +detection, innocence declares its confidence, and hope anticipates +with bright expectation." + +_Observation._ The fifth pair of nerves (fig. 126) is distributed to +the parts of the face on which the seventh pair ramifies. The former +serves for sensation, the latter for motion. Thus, when the seventh +pair of nerves is divided, or its functions destroyed by disease, the +side affected loses all power of expression, though sensation remains +unaffected. On the contrary, if we divide the fifth pair, sensation is +entirely destroyed, while expression remains. + + -=-=-=-=-=-=-=-=-=-=-=-= + +789. Are they also the instruments of expression, either of joy or +grief? 790. What is said in reference to the seventh pair of nerves? +Where is the fifth pair of nerves distributed? + + -=-=-=-=-=-=-=-=-=-=-=-= + +791. 5th. _The sympathetic nerve._ This nerve confers vitality on all +the important portions of the system. It exerts a controlling +influence over the involuntary functions of digestion, absorption, +secretion, circulation, and nutrition. Every portion of the body is, +to a certain extent, under its influence, as filaments from this +system of nerves accompany the blood-vessels throughout their course. + +792. An important use of the sympathetic nerve is to form a +communication of one part of the system with another, so that one +organ can take cognizance of the condition of every other, and act +accordingly. If, for example, disease seizes the brain, the stomach, +by its sympathetic connection, knows it; and as nourishment would add +to the disease, it refuses to receive food, and perhaps throws off +what has already been taken. Loss of appetite in sickness is thus a +kind provision of nature, to prevent our taking food when it would be +injurious; and following this intimation, we, as a general rule, +should abstain from food until the appetite returns. + +[Illustration: Fig. 133. A back view of the brain and spinal cord. 1, The +cerebrum. 2, The cerebellum. 3, The spinal cord. 4, Nerves of the face. +5, The brachial plexus of nerves. 6, 7, 8, 9, Nerves of the arm. 10, +Nerves that pass under the ribs, 11, The lumbar plexus of nerves. 12, The +sacral plexus of nerves 13, 14, 15, 16, Nerves of the lower limbs.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is the function of this nerve? What is the effect if the seventh +pair is divided, or its function destroyed by disease? 791. What is +said of the sympathetic nerve? 792. What is the use of the sympathetic +system? Explain fig. 133. + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Note._ Let the anatomy and physiology of the nervous system be +reviewed from figs. 131, 132, 133, or from anatomical outline plate. +No. 8. + + + + +CHAPTER XXXIX. + +HYGIENE OF THE NERVOUS SYSTEM. + + +793. As the different organs of the system are dependent on the brain +and spinal cord for efficient functional action, and as the mind and +brain are closely associated during life, the former acting in strict +obedience to the laws which regulate the latter, it becomes an object +of primary importance in education, to discover what these laws are, +that we may escape the numerous evils consequent on their violation. + +794. _For healthy and efficient action, the brain should be primarily +sound_; as this organ is subject to the same general laws as other +parts of the body. If the brain of the child is free from defects at +birth, and acquires no improper impressions in infancy, it will not +easily become diseased in after life. But, if the brain has inherited +defects, or has acquired a proneness to disease by mismanagement in +early life, it will more easily yield to influences that cause +diseased action. The hereditary tendency to disease is one of the most +powerful causes that produce nervous and mental affections. +Consequently, children have a strong tendency to the diseases from +which the parents suffered. + +795. When both parents have similar defects, or have descended from +tainted families, the children are usually more deeply impressed with +their imperfections than when only one possesses the defect. This is +the reason of the frequency of nervous disease and imbecility among +the opulent, as intermarriages among near relations are more frequent +with this class than among the poor. + + -=-=-=-=-=-=-=-=-=-=-=-= + +793-850. _Give the hygiene of the nervous system._ 793. Why is it +important to know the laws which regulate the action of the brain? +794. What is necessary that the action of the brain be healthy and +efficient? What follows if the brain of the child has inherited +defects? 795. What is the effect when both parents possess similar +defects? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Among some of the reigning families of Europe, +particularly the Spanish, the folly of intermarriage among themselves +is strongly illustrated. The high and noble talents that characterized +their progenitors are not seen, but there is now exhibited, among +their descendants, imbecility and the most revolting forms of nervous +disease. + +796. "Unhappily, it is not merely as a cause of disease, that +hereditary predisposition is to be dreaded. The obstacles which it +throws in the way of permanent recovery are even more formidable, and +can never be entirely removed. Safety is to be found only in avoiding +the perpetuation of the mischief." + +797. "Therefore, if two persons, each naturally of excitable and +delicate nervous temperament, choose to unite for life, they have +themselves to blame for the concentrated influence of similar +tendencies in destroying the health of their offspring, and +subjecting them to all the miseries of nervous disease, madness, or +melancholy." The command of God not to marry within certain degrees +of consanguinity, is in accordance with the organic laws of the +brain, and the wisdom of the prohibition is confirmed by observation. + +_Observation._ The inhabitants, females particularly, of the sea-girt +islands of America, are more affected with nervous diseases, than +those who reside upon the mainland. The prevalence of these affections +is ascribed to the frequent intermarriage of persons closely related +by blood. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is one cause of nervous disease among the higher classes? What is +true of some of the reigning families of Europe? 796. Why is +hereditary predisposition to be dreaded? 797. Is the prohibition of +God respecting intermarriage in accordance with the organic laws of +the brain? What is said of the inhabitants of the sea-girt islands of +America? + + -=-=-=-=-=-=-=-=-=-=-=-= + +798. _The brain requires a due supply of pure blood._ This organ +receives an unusually large supply of blood, in comparison with the +rest of the body. It is estimated that one tenth of all the blood sent +from the heart goes to this organ. If the arterial blood be altogether +withdrawn, or a person breathes air that is filled with carbonic gas, +the brain ceases its proper action, and sensibility with consciousness +becomes extinct. + +_Illustrations._ 1st. If a person lose a considerable quantity of +blood, dizziness and loss of consciousness follow. This results from +the brain not receiving a sufficient amount of blood to sustain its +functions. + +2d. When an individual descends into a well or pit that contains +carbonic acid, the blood is not changed or purified in the lungs, and +loss of consciousness and death soon follow. + +799. The slighter variations in the state of the blood have equally +sure, though less palpable effects. If its vitality is impaired by +breathing an atmosphere so much vitiated as to be insufficient to +produce the proper degree of oxygenation, the blood then affords an +imperfect stimulus to the brain. As a necessary consequence, languor +and inactivity of the mental and nervous functions ensue, and a +tendency to headache, fainting, or hysteria, makes its appearance. + +_Observations._ 1st. Let a person remain, for a time, in a crowded, +ill-ventilated, hall or church, and headache or faintness is generally +produced. This is caused by the action of impure blood upon the +brain. + +2d. If a school-teacher wishes to have his pupils, on the day of +examination, appear creditably, he will be careful to have the room +well ventilated. Ventilating churches might prevent the inattention +and sleepiness that are observed during the afternoon service. + + -=-=-=-=-=-=-=-=-=-=-=-= + +798. Why does the brain require a due supply of pure blood? What is +the effect when a person loses a considerable quantity of blood? What +causes the loss of consciousness when carbonic acid is breathed? 799. +What effects are produced by slight variations in the quality of the +blood? From the following observations, give some of the effects of +impure blood on the brain. + + -=-=-=-=-=-=-=-=-=-=-=-= + +3d. In many instances, the transmission of imperfectly oxygenated +blood to the brain, is an influential cause in the production of +nervous disease and delicacy of constitution. The only efficient +remedy for these conditions is a supply of pure blood to the brain. + +800. _The brain should be called into action._ This organ, like the +muscles, should be used, and then allowed to rest, or cease from +vigorous thought. When the brain is properly called into action by +moderate study, it increases in size and strength; while, on the other +hand, if it is not used, the action of this organ is enfeebled, +thereby diminishing the function of all parts of the body. + +801. The brain, being an organized part, is subject, so far as regards +exercise, to the same laws as the other organs of the body. If it is +doomed to inactivity, its size diminishes, its health decays, and the +mental operations and feelings, as a necessary consequence, become +dull, feeble, and slow. If it is duly exercised after regular +intervals of repose, the mind acquires readiness and strength. Lastly, +if it is overtasked, either in the force or duration of its activity, +its functions become impaired, and irritability and disease take the +place of health and vigor. + +802. The consequences of inadequate exercise will first be explained. +We have seen that by disuse the muscles become emaciated, the bones +soften, and the blood-vessels are obliterated. The brain is no +exception to this general rule. It is impaired by permanent +inactivity, and becomes less fit to manifest the mental powers with +readiness and energy. Nor will this surprise any reflecting person, +who considers that the brain, as a part of the same animal system, is +nourished by the same blood and regulated by the same vital laws as +the muscles, bones, and arteries. + + -=-=-=-=-=-=-=-=-=-=-=-= + +800. Why should the brain be called into action? 801. What is the +effect if the brain is doomed to inactivity? 802. Show the consequences +of disuse of the organs mentioned in preceding chapters. Does the +same principle apply to the brain? + + -=-=-=-=-=-=-=-=-=-=-=-= + +803. It is the weakening and depressing effect which is induced by the +absence of the stimulus necessary for the healthy exercise of the +brain, that renders solitary confinement so severe a punishment, even +to the most daring minds. Keeping the above principle in view, we +shall not be surprised to find that _non-exercise_ of the brain and +nervous system, or, in other words, inactivity of intellect and +feeling, is a very frequent predisposing cause of every form of +nervous disease. + +804. For demonstrative evidence of this position, we have only to look +at the numerous victims to be found among females of the middle and +higher ranks, who have no calls to exertion in gaining the means of +subsistence, and no objects of interest on which to exercise their +mental faculties, and who, consequently, sink into a state of mental +sloth and nervousness, which not only deprives them of much enjoyment, +but subjects them to suffering, both of body and mind from the +slightest causes. + +805. But let the situation of such persons be changed; bring them, for +instance, from the listlessness of retirement to the business and +bustle of the city; give them a variety of imperative employments, and +so place them in society as to supply to their cerebral organs that +extent of exercise which gives health and vivacity of action, and in a +few months the change produced will be surprising. Health, animation, +and energy, will take the place of former insipidity and dulness. + +806. An additional illustration, involving an important principle in +the production of many distressing forms of disease will be found in +the case of a man of mature age, and of active habits, who has devoted +his life to the toils of business, and whose hours of leisure have +been few and short. Suppose such a person to retire to the country in +search of repose, and to have no moral, religious, or philosophical +pursuits to occupy his attention and keep up the active exercise of +his brain; this organ will lose its health, and the inevitable result +will be, weariness of life, despondency, or some other variety of +nervous disease. + + -=-=-=-=-=-=-=-=-=-=-=-= + +803. What renders solitary confinement so severe a punishment to the +most daring minds? What is a predisposing cause of nervous disease? +804. In what classes do mental and nervous debility prevail? 805. How +can this be counteracted? 806. Give another illustration, showing how +disease of the brain is induced. + + -=-=-=-=-=-=-=-=-=-=-=-= + +807. One great evil attending the absence of some imperative +employment or object of interest, to exercise the mind and brain, is +the tendency which it generates to waste the mental energies on every +trifling occurrence which presents itself, and to seek relief in the +momentary excitement of any sensation, however unworthy. The best +remedy for these evils is to create occupation to interest the mind, +and give that wholesome exercise to the brain, which its constitution +requires. + +808. _The evils arising from excessive or ill-timed exercise of the +brain, or any of its parts, are numerous._ When we use the eye too +long, or in too bright a light, it becomes bloodshot. The increased +action of its vessels and nerves gives rise to a sensation of fatigue +and pain, requiring us to desist. If we relieve the eye, the +irritation gradually subsides and the healthy state returns. But, if +we continue to look intently, or resume our employment before the eye +has regained its natural state by repose, the irritation at last +becomes permanent, and disease, followed by weakness of vision, or +even blindness, may ensue. + +809. Phenomena precisely analogous occur, when, from intense mental +excitement, the brain is kept long in a state of excessive activity. +The only difference is, that we can always see what happens in the +eye, but rarely what takes place in the brain; occasionally, however, +cases of fracture of the skull occur, in which, part of the bone being +removed, we can see the quickened circulation in the vessels of the +brain, as easily as those of the eye. + + -=-=-=-=-=-=-=-=-=-=-=-= + +807. What is one great evil attending the absence of some imperative +employment to exercise the mind and brain? What is the true remedy for +these evils? 808. From what other cause do evils arise to the brain? +Explain the evil of it by the excessive use of the eye. 809. What is +the only difference in the analogy of the phenomena of the eye and +brain? Has the analogy been verified? + + -=-=-=-=-=-=-=-=-=-=-=-= + +810. Sir Astley Cooper had a young man brought to him, who had lost a +portion of his skull, just above the eyebrow. "On examining the head," +says Sir Astley, "I distinctly saw that the pulsation of the brain was +regular and slow; but at this time he was agitated by some opposition +to his wishes, and directly the blood was sent with increased force to +the brain, and the pulsation became frequent and violent." + +811. Indeed, in many instances, the increased circulation in the +brain, attendant on mental excitement, reveals itself when least +expected, and leaves traces after death, which are very perceptible. +When tasked beyond its strength, the eye becomes insensible to light, +and no longer conveys any impressions to the mind. In like manner, the +brain, when much exhausted, becomes incapable of thought, and +consciousness is almost lost in a feeling of utter confusion. + +812. _At any time of life, excessive and continued mental exertion is +hurtful_; but in infancy and early youth, when the structure of the +brain is still immature and delicate, permanent mischief is more +easily produced by injudicious treatment than at any subsequent +period. In this respect, the analogy is as complete between the brain +and the other parts of the body, as that exemplified in the injurious +effects of premature exercise of the bones and muscles. + +813. Scrofulous and rickety children are the most usual sufferers in +this way. They are generally remarkable for large heads, great +precocity of understanding, and small, delicate bodies. But in such +instances, the great size of the brain, and the acuteness of the mind, +are the results of morbid growth. Even with the best of management, +the child passes the first years of its life constantly on the brink +of active disease. + + -=-=-=-=-=-=-=-=-=-=-=-= + +810. Relate the case detailed by Sir Astley Cooper. 811. May the +increased functional action of the brain change its structure? 812. At +what age particularly is excessive and continued mental exertion +hurtful? 813. What is said of scrofulous and rickety children? + + -=-=-=-=-=-=-=-=-=-=-=-= + +814. Instead, however, of trying to repress its mental activity, the +fond parents, misled by the early promise of genius too often excite +it still further, by unceasing cultivation, and the never-failing +stimulus of praise. Finding its progress for a time equal to their +warmest wishes, they look forward with ecstasy to the day when its +talents will break forth and shed lustre on its name. + +815. But in exact proportion as the picture becomes brighter to their +fancy, the probability of its being realized becomes less; for the +brain, worn out by premature exertion, either becomes diseased, or +loses its tone, leaving the mental powers imbecile and depressed for +the remainder of life. The expected prodigy is thus easily outstripped +in the social race by many whose dull outset promised him an easy +victory. + +816. Taking for our guide the necessities of the constitution, it will +be obvious that the modes of treatment commonly resorted to ought to +be reversed. Instead of straining to the utmost the already irritable +powers of the precocious child, and leaving his dull competitor to +ripen at leisure, a systematic attempt ought to be made, from early +infancy, to rouse to action the languid faculties of the latter, while +no pains ought to be spared to moderate and give tone to the activity +of the former. + +817. Instead of this, however, the prematurely intelligent child is +sent to school and tasked with lessons at an unusually early age, +while the healthy but more backward boy, who requires to be +stimulated, is kept at home in idleness, perhaps for two or three +years longer, merely on account of his backwardness. A double error is +here committed. The consequences to the intelligent boy are, +frequently, the permanent loss both of health and of his envied +superiority of intellect. + + -=-=-=-=-=-=-=-=-=-=-=-= + +814. How are such children usually managed? 815. What is the cause of +their early promise and subsequent disappointment? 816. What mode of +treatment should be adopted in educating precocious children? 817. How +should the dull or less active child be treated? What is the usual +course? + + -=-=-=-=-=-=-=-=-=-=-=-= + +818. In youth, too, much mischief is done by the long daily period of +attendance at school, and the continued application of the mind which +the ordinary system of education requires. The law of exercise--that +long-sustained action exhausts the vital powers of the organ--applies +as well to the brain as to the muscles. Hence the necessity of varying +the occupations of the young, and allowing frequent intervals of +exercise in the open air, instead of "enforcing the continued +confinement now so common." + +_Observation._ It is no unusual occurrence, that on examination day, +the best scholars appear indifferently. This may be the result of +nervous exhaustion, produced by extra mental effort in preparing for +the final examination. It is advisable for such pupils to divert their +minds from close study for a few days previous to examination. During +this time, the student may indulge in physical recreation, social +intercourse, and a moderate amount of reading. + +819. "In early and middle life, fever, an unusual degree of cerebral +disorder, is a common consequence of the excessive and continued +excitement of the brain. This unhappy result is brought on by severe +study, unremitted mental exertion, anxiety, and watching. Nervous +disease, from excessive mental labor and high mental excitement, +sometimes shows itself in another form. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What are the consequences of the error? 818. What error prevails in +the present system of education? Why should youths be allowed frequent +intervals to exercise in the open air? Give observation. 819. What is +a frequent consequence of continued and excessive excitement of the +brain? + + -=-=-=-=-=-=-=-=-=-=-=-= + +820. "From the want of proper intervals of rest, the vascular +excitement of the brain has not time to subside. A restless +irritability of temper and disposition comes on, attended with +sleeplessness and anxiety, for which no external cause can be +assigned. The symptoms gradually become aggravated, the digestive +functions give way, nutrition is impaired, and a sense of wretchedness +is constantly present, which often leads to attempts at suicide." + +_Observations._ 1st. Moderation in mental exertion is more necessary +in old age than in early or mature years. In youth and manhood, the +exhaustion of the brain from over-excitement may be repaired, but no +such result follows over-exertion in the decline of life. "What is +lost then, is lost forever." At that period, the brain becomes +excited, and is soon exhausted when forced to protracted and vigorous +thought. Sir Walter Scott and President Harrison afford sad examples +of premature death from overtasked brains at an advanced period of +their lives. + +2d. If the mind is incessantly engaged in the contemplation of the +same object, there is danger from over-exertion of the brain at any +period of life, but more particularly in old age. The more limited the +sphere of mental action, the greater the danger of the brain being +over-exercised. Hence the frequency of nervous diseases in poets, +mathematicians, and musicians. + + -=-=-=-=-=-=-=-=-=-=-=-= + +820. What often manifests itself from the want of proper intervals of +rest? Why is moderation in mental action necessary in old age? What is +the effect if the mind is incessantly engaged in the contemplation of +the same object? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XL. + +HYGIENE OF THE NERVOUS SYSTEM, CONTINUED. + + +821. Having pointed out the evils arising both from inadequate and +from excessive mental exertion, it remains to direct the attention to +some of the rules which should guide us in the exercise of the brain. + +822. _We should not enter upon continued mental exertion, or arouse +deep feeling, immediately before or after a full meal._ Such is the +connection between the mind and body, that even in a perfectly healthy +person, unwelcome news, sudden anxiety, or mental excitement, +occurring soon after eating, will impede digestion, and cause the +stomach to loathe the masticated food. + +823. The worst forms of indigestion and nervous depression are those +which arise from excessive mental application, or depressed feeling, +conjoined with unrestrained indulgence in the pleasures of the table. +In such circumstances, the stomach and brain react upon and disturb +each other, till all the horrors of nervous disease make their +unwelcome appearance, and render life miserable. Too many literary men +and students know this from sad experience. + +824. _We should engage in intense study in the early part of the day._ +Nature has allotted the darkness of the night for repose, and for +restoration by sleep of the exhausted energies of mind and body. In +the early part of the evening, if study or composition be ardently +engaged in, the increased action of the brain, which always +accompanies activity of mind, requires a long time to subside. If the +individual possesses a nervous temperament, he will be sleepless for +hours after he has retired, or perhaps be tormented by unpleasant +dreams. + + -=-=-=-=-=-=-=-=-=-=-=-= + +822. Why should we not arouse deep feeling immediately before or after +eating a full meal? 823. How are the worst forms of indigestion and +nervous depression produced? What class of men know this from sad +experience? 824. What evils arise from studious application at night? + + -=-=-=-=-=-=-=-=-=-=-=-= + +825. It is, therefore, of great advantage to enter upon intense mental +application early in the day, and to devote several of the hours which +precede bedtime to entertaining conversation, music, and lighter +reading. The vascular excitement previously induced in the brain by +study, has then time to subside, and sound, refreshing sleep is much +more certainly obtained. This rule is of great consequence to those +who are obliged to undergo much mental labor. + +_Observation._ The idea of gathering wisdom by burning the "midnight +oil," is more poetical than profitable. The best time to use the brain +is during the day. + +826. _The close student and the growing child need more sleep than the +idler or the adult._ As steep is the natural repose of all organs, it +follows that the more the brain and other organs of the system are +employed, the more repose they require. The organs of the child, +beside sustaining their proper functions, are busy in promoting its +growth. This nutritive process is attended with a certain degree of +exhaustion. The impaired health of children often results from a +disregard of this principle. But, on the other hand, an excess of +sleep produces feebleness, by preventing the proper exercise of the +mind as well as the body. + +827. _The length of time the brain may be advantageously used, is +modified by many circumstances._ The power of the brain in different +persons to endure action, is various. This is modified by its primary +character; by development and age; by habits of action; by the health +of the cerebral organ and general system; by the moral feelings and +other conditions. + + -=-=-=-=-=-=-=-=-=-=-=-= + +825. Why should we engage in intense study in the early part of the +day? 826. What persons require the most sleep? Why? 827. What is said +relative to the length of time that the brain can be advantageously +used? Give a condition that modifies the amount of mental labor. + + -=-=-=-=-=-=-=-=-=-=-=-= + +828. The primary physical organization of some individuals is such, +that they are enabled to endure with impunity an amount of mental +labor that would disorder, if not destroy functionally, the cerebral +organ of others differently constituted. Napoleon Bonaparte was of +this number. There can be no fixed period for mental labor, that may +be adopted as a rule for all persons whose systems are maturely +developed. Much less is there a proper definite period for study, that +is applicable to all children. + +_Observation._ The practice of retaining pupils of all ages, from five +to twenty years, in the school-room the same period of time, for the +purpose of study, is not predicated upon any law of physiology. An +exercise of three hours, with one or two recesses of ten minutes each, +may profit the eldest class; two hours with a recess of ten minutes, +the middle class; while one hour, or one hour and a half, with one +recess, would be as long a period as the youngest pupils should be +retained in the study-room at one session. + +829. A person who is accustomed to muscular exertion will endure a +longer period of physical toil than one who is not inured to it. So it +is with mental labor. If the brain has been habituated to mental +action and profound study, it will not be so soon fatigued as when not +accustomed to such exertions; consequently, an amount of mental labor +may be performed with impunity at one time, that would exhaust and +cause serious disease of the cerebral organ at another. + +_Observation._ Persons that commence a course of study at a late +period in life, frequently evince their zeal at the commencement by +poring over their books twelve or more hours each day. The progress of +such students is soon arrested by physical and mental depression. In +such instances, it would be more judicious to commence with only three +or four hours' vigorous application each day, and gradually protract +the period of study five or more minutes every successive day, until +the brain may be called into vigorous action six or eight hours with +impunity. + + -=-=-=-=-=-=-=-=-=-=-=-= + +828. Why can there be no fixed period for mental labor? What is said +of the practice of retaining pupils of all ages the same period of +time in the school-room? 829. Show that the action of the brain is +influenced by habit, as well as the muscular system. What suggestion +to those persons that commence a course of study at a late period in +life? + + -=-=-=-=-=-=-=-=-=-=-=-= + +830. The amount of mental power is greatly influenced by the general +health. Such is the intimate connection of the different parts of the +system, particularly the digestive apparatus, with the cerebral +organs, that except there be vigor of constitution, and freedom from +disease, mental efforts will be feeble and of little avail. + +_Observation._ The prevalent opinion, that individuals who are feeble +or diseased may acquire a collegiate education, and thus become useful +to themselves and the community, is very generally erroneous. Such +persons should enter upon a daily and systematic course of physical +training, and their labor should be in the open air, in order that the +system may be invigorated and freed from disease. + +831. The moral feelings exert a controlling influence over the +functions of the muscular, digestive, and respiratory organs. They +also exert an influence, perhaps, more powerful upon the nervous +system. While fear and anxiety depress, hope and the enlivening +emotions, facilitate the functional activity of the brain, and +increase its power for mental exertion. By a proper and systematic +education of the moral feelings, they are not only a source of +happiness, and productive of right conduct, but aid in the culture of +the intellect. Consequently, we should cultivate a feeling of hopeful +trust in the future, and a firm reliance upon the laws which the +Creator has given us for our guidance. + + -=-=-=-=-=-=-=-=-=-=-=-= + +830. Show that the amount of mental power is modified by the general +health. What is said of feeble persons acquiring a collegiate +education? 831. Do the moral feelings exert a controlling influence +over the principal functions of the system? What is the effect of a +proper and systematic culture of the moral feelings? + + -=-=-=-=-=-=-=-=-=-=-=-= + +832. _Regularity is very important in exercising the moral and +intellectual powers._ Periodicity, or a tendency to resume the same +mode of action at stated times, is peculiarly the characteristic of +the nervous system. If we repeat any kind of mental effort every day +at the same hour, we at last find ourselves entering upon it without +premeditation when the time approaches. In like manner, if we arrange +our studies in accordance with this law, and take up each in the same +order, a natural aptitude is soon produced, which renders application +more easy than by resuming the subjects as accident may direct. + +_Observation._ When engaged in abstruse studies, it may be found +advantageous to pursue others that are less difficult. The intense +application of the brain, which is requisite in the one instance, is +relieved by directing the attention to a study that requires less +thought. By this change, there is mental relaxation attended with +invigoration of the cerebral organ. Or, it may be explained by +assuming, that the brain is composed of an aggregate of distinct +organs, each of which is called into action in pursuing different +studies. + +833. Effective study is impossible if the powers of the brain are +depressed. When the cerebral organ has been temporarily debilitated by +protracted intellectual efforts, it is ineffectual to attempt any +concentrated mental exercise. This condition of the nervous system is +indicated by confusion of thought and inability to attain results that +usually follow similar efforts. Mental rest in these cases is +required. + +_Observation._ Students frequently fail in solving mathematical +problems when the mind is prostrated by continued and excessive effort +to obtain a solution. Not unfrequently after a night's rest the +problem is quickly solved, and the pupil thinks he "dreamed it out." +The true explanation is rest invigorated the exhausted brain, which +fitted it for vigorous and successful thought. + + -=-=-=-=-=-=-=-=-=-=-=-= + +832. Why is regularity of great importance in exercising the moral and +intellectual powers? What suggestion when pursuing abstruse studies? +How explained? 833. When is effective study impossible? How is this +condition of the nervous system indicated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +834. _The intellect should not be cultivated to the neglect of the +moral and physical powers._ All the faculties require for their +development regular exercise, alternated with intervals of rest. This +is as necessary to the due development of the moral feelings of a +child as in physical training and mental culture. Consequently, those +schools are to be preferred in the education of youth, where the +physical, intellectual, and moral faculties receive each day a due +share of attention and culture. + +835. The continuance of healthy and vigorous action in the matured +physical, mental, and moral powers, requires frequent and regular +action, alternated with rest, as much as in their development. +Consequently, those who cultivate one or two of these faculties, to +the neglect of the others, exhibit a marked deficiency of acuteness +and vigor in those not exercised. This defect reacts on the powers +that are vigorous, diminishing the energy and deteriorating all the +other faculties of man. + +_Observations._ 1st. If the principles before mentioned are true, the +adult, as well as the child, should spend a part of each day in some +proper physical employment; another portion should be appropriated to +intellectual pursuits; while another should be sedulously devoted to +the cultivation of the moral feelings. + +2d. Disease of the corporeal system more frequently occurs when only +one set of faculties is used than when all are equally employed. This +is particularly true of nervous and mental disease, which follows and +is caused by either high intellectual action, or intense moral +emotions, without a due amount of physical exercise. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is the "dreaming out" of problems explained? 834. What is said of +the culture of the intellect? What schools are preferable in the +education of youth? Why? 835. What is the effect of cultivating only +one faculty of the mind? Give observation 1st. Observation 2d. + + -=-=-=-=-=-=-=-=-=-=-=-= + +836. _The brain can exercise its full force upon only one object at a +time._ If its energies are directed to two or more operations, neither +will receive that full power of exertion that it would if only one +object had engaged the mind. Although the brain will direct several +operations at the same time when only slight mental effort is +required, yet when one operation becomes difficult, or demands special +attention of the mind, the other will be suspended. This is +illustrated in social conversation while walking. Let it become +necessary to concentrate the nervous power upon the motor organs, and +the conversation declines or ceases. + +837. In acquiring an education, or in pursuing any profession or +trade, none of those influences that promote the proper functions of +the body, and tend to increase physical ease, should be neglected. +For, if the brain is occupied with disagreeable sensations, it cannot +concentrate its power as effectively in the various employments of +man. + +_Observations._ 1st. The situation, ventilation, light, and warmth of +a school-room, together with the arrangement of the benches, do much +to influence the concentration or distraction of the operations of the +mind. Let there be attached to the school-house a spacious yard +planted with trees; let its architecture be attractive; let the +windows be arranged with regularity, and not with the elevation of a +convict's cell, and the benches, in every respect, be adapted to the +different scholars, so that the position of each may be comfortable, +and we mistake if there is not a greater improvement, in a given +time, in such a school, than where there is an apparent disregard to +the pleasure or comfort of the scholars. + + -=-=-=-=-=-=-=-=-=-=-=-= + +836. What is the effect if the brain concentrates its energies on more +than one object at a time? How illustrated? 837. What should be +regarded in pursuing any employment? Why? What is said in reference to +the arrangement of school-rooms? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. Mechanics' shops should receive as much attention, relative to +their situation, light, warmth, &c., as school-rooms. If these are +duly observed, the nervous influence transmitted from the brain to the +muscles will be more stimulating, as well as more abundant; +consequently, labor will be performed with less exhaustion. + +838. _Repetition is necessary to make a durable impression on the +mind._ "The necessity of judicious repetition in mental and moral +education, is, in fact, too little adverted to, because the principle +which renders it efficacious has not been understood. To induce +facility of action in the organs of the mind, practice is as essential +as it is in the organs of motion. + +839. "In physical education we are aware of the advantages of +repetition. We know that if practice in dancing, fencing, skating, and +riding, is persevered in for a length of time sufficient to give the +muscles the requisite promptitude and harmony of action, the power +will be ever afterward retained, although little called into use; +whereas, if the muscles have not been duly trained, we may reiterate +practice at different intervals, without proportionate advancement. +The same principle applies equally to the moral and intellectual +powers, because these operate by means of material organs. + +840. "According to this principle, it follows, that in learning a +language or science, six successive months of application will be more +effectual in fixing it in the mind and making it a part of its +furniture, than double or treble the time, if the lessons are +interrupted by long intervals. Hence it is a great error to begin and +study, and then break off, to finish at a later period. The fatigue +is thus doubled, and the success greatly diminished. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Of mechanics' shops? 838. Is repetition necessary to make a durable +impression on the mind? Why? 839. How is it with physical education? +840. What follows, according to this principle? + + -=-=-=-=-=-=-=-=-=-=-=-= + +841. "The best way is to begin at the proper age, and to persevere +till the end is attained. This accustoms the mind to sound exertion, +and not to _fits_ of attention. Hence the evil arising from long +vacations; and also the evil of beginning studies before the age at +which they can be understood, as in teaching children the abstract +rules of grammar, to succeed in which, implies in them a power of +thinking, and an amount of general knowledge, which they do not +possess." + +842. _The skull is susceptible of fractures from slight blows._ This +occurs most frequently when the blow is given on the side of the head +above and anterior to the ear. Here the bone is very thin, and often +quite brittle. For these reasons, no instructor, or any person, should +punish a child by striking upon any portion of the head. + +_Observation._ A few years since, a teacher in one of the Middle +States gave a pupil a slight blow upon the head. It fractured the +skull and ruptured a blood-vessel of the brain, causing a loss of +consciousness, and finally death. + +843. _Concussion of the brain may be produced by blows, or by +violently shaking a person._ As the brain is of pulpy consistence, the +atoms of which it is composed, and the circulation of blood in its +minute vessels, may be disturbed by the vibration from a blow on the +exterior of the skull-bones. This disturbance of the cerebral organ is +attended with unpleasant sensations, dizziness, loss of memory and +consciousness. These may be followed by headache and inflammation of +the brain. Concussion of the brain, and the results above mentioned, +may be produced by the sudden motion attendant on the violent shaking +of a scholar. Consequently, a child should never be seized by the arm +and shaken violently as a method of chastisement. + + -=-=-=-=-=-=-=-=-=-=-=-= + +841. What is the best way of learning the sciences? 842. Why should +not a child be struck upon any portion of the head? What observation +in this connection? 843. How may concussion of the brain be produced? +What is the effect of each upon the brain of the child? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ Most persons have experienced a disagreeable sensation +and dizziness, caused by falling from a slight elevation, or by +jumping from a carriage. This is the result of a moderate concussion +of the brain. + +844. In injuries of the brain, from blows and falls, the symptoms +are usually alarming, and all should possess some information for +such contingencies. In general, such accidents are attended by +insensibility; the skin and extremities are pale and cold, the +pulse is very weak and feeble, and the circulation is less vigorous; +the respiration, also, is less frequent and full. + +845. When these symptoms exist, the individual, in the first instance, +should be placed in pure air, and friction and dry warmth should be +applied to the pallid and cold skin. This should be assiduously +persevered in until heat and color are restored to the skin and limbs, +and due action of the heart and arteries has been established. Mild +stimulants may also be used internally, with much advantage. The +sympathizing friends should not be permitted to stand about the +patient, as they vitiate the air. There should be no bleeding until +the skin and extremities become warm. Send for a surgeon without +delay. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give an instance where moderate concussion of the brain is produced. +844. What are the symptoms when the brain is injured from blows and +falls? 845. What treatment should be adopted? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLI. + +THE SENSE OF TOUCH. + + +846. SENSATION is the perception of external objects by means of the +senses. There are five senses, namely, _Touch_, _Taste_, _Smell_, +_Hearing_, and _Vision_. + +847. TOUCH is the sense by which the mind becomes acquainted with some +of the properties of bodies, and enables us determine whether their +surfaces are smooth or rough, their relative temperature, and, to a +certain degree, their form and weight. + +848. Some physiologists make a distinction between the sense of touch +and tact. Tact, or feeling, is more general, extending over the whole +surface of the skin and mucous membranes, while touch exists chiefly +in the fingers of man and in the noses of certain quadrupeds. + +849. "In the exercise of these functions, tact is considered passive; +as, when any part of the system comes into contact with another body, +a sensation of its presence is given, without the exercise of +volition. On the contrary, touch is active, and is exercised +voluntarily, for the purpose of conveying to the mind a knowledge of +the qualities or properties of the surfaces of bodies; as when we feel +of a piece of cloth to ascertain its qualities, or a polished surface, +to prove its smoothness." + +850. In man, the hand is admirably adapted to the exercise of touch. +"The fineness of the skin, its great sensibility, the species of +cushion formed by the sub-cutaneous fat at the extremities of the +fingers, the length and flexibility of these organs, and the +capability of opposing the thumb to the fingers, like a pair of +forceps, are so many conditions essentially favorable to the delicacy +of this sense, and enable us to appreciate with exactitude the +qualities of the bodies we may feel." + + -=-=-=-=-=-=-=-=-=-=-=-= + +846. Define sensation. How many senses have we? 847-851. _What is said +of the sense of touch?_ 847. Define touch. 848. What is the difference +between touch and tact? 849. In the exercise of these functions, which +is active, and which passive? 850. Why is the hand so admirably +adapted to the exercise of the sense of touch? + + -=-=-=-=-=-=-=-=-=-=-=-= + +851. The nerves that supply the sense of touch, proceed from the +anterior half of the spinal cord. Where this sense is most acute and +delicate, we find the greatest number of sensitive nervous filaments, +and those of the largest size. + +_Observation._ In amputating limbs, and other surgical operations, the +division of the skin causes more pain than all the subsequent steps of +the operation, however protracted. The muscles, cellular membrane, and +fat have but little sensibility; while the bones, tendons, and +ligaments are insensible when not diseased, and may be cut without +causing pain. + + +HYGIENE OF THE SENSE OF TOUCH. + +852. The sense of touch varies in different persons, and also in +individuals of different ages. Thus the sensibilities of the child are +more acute than those of the aged. Although there is an original +difference of sensibility from organization, still, the function of +the nerves of sensation is modified by certain influences. + +853. _The healthy or unhealthy, active or inactive state of the brain, +influences the action of the sensitive nerves._ In sound and perfect +sleep, the brain is inactive. In this state, ordinary impressions made +upon the skin are not observed by the sleeping person. Thus the arm +may be blistered while sleeping, when exposed to the warm rays of the +sun, and the individual will not be aware of it at the time. + + -=-=-=-=-=-=-=-=-=-=-=-= + +851. From what do the nerves proceed that supply this sense? 852-864. +_Give the hygiene of the sense of touch._ 852. Does this sense vary in +different persons? 853. Mention a condition of the brain that +influences the nerves of sensation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +854. If there is compression of the brain, as when the skull-bones are +depressed, or disease of this organ exists, as in severe typhus fever, +impressions made upon the nerves of the skin will not be noticed. The +same is true when the mind is engaged in intense thought or study; +heat or cold may be so intense as to disorganize the skin, and not to +be noticed. + +855. The varying health or condition of the brain usually depresses or +increases the sensitiveness of the skin. This is seen in grief and +fear, which diminish, while hope and joy increase the impressibility +of this tissue. It is not uncommon to see the unfortunate insane +endure exposure to heat and cold with seeming impunity; whereas it +would induce almost insupportable suffering to the sane man. Diseases +of the heart, stomach, and lungs, alter the condition of the brain, +and modify, to a greater or less degree, the sensitiveness of the +skin. + +856. _The state of the conducting nervous trunks influences the nerves +of sensation._ If a nervous trunk is compressed or divided, the parts +supplied by nervous filaments from this branch, will be insensible to +the impressions made upon them, and consequently such impressions are +not transmitted to the brain. + +_Observation._ When the inside of the arm or lower extremities rests +upon a hard surface, the nerves may be compressed so as to deprive the +parts of sensibility. This condition is called "numbness." + +857. _The quantity of blood supplied to the skin modifies its +sensitiveness._ If the quantity of blood is diminished, the +sensibility of the skin will be impaired. This is demonstrated by +noting the effects of cold upon the cutaneous tissue, the application +of which contracts the blood-vessels, and drives the circulating fluid +from this membrane, which is shown by the paleness, as well as by the +shrivelled appearance of the skin. And, if this tissue is wounded +while under the influence of cold, but little pain will be felt, and +this chilling influence may be carried so far as not only to deprive +the part of sensation, but of vitality. + + -=-=-=-=-=-=-=-=-=-=-=-= + +854. Mention other conditions that affect these nerves. 855. What is +the effect of the varying health or condition of the brain upon the +sensitiveness of the skin? Give instances of this effect. 856. What is +the result if a nervous trunk is divided or compressed? How may +"numbness" in the limbs be produced? 857. Does the quantity of blood +supplied to the skin affect its sensibility? + + -=-=-=-=-=-=-=-=-=-=-=-= + +858. The influence of the blood upon the sensibility of the skin, is +further demonstrated by the pain experienced when chilled extremities +are suddenly exposed to heat. The nerves, by the sudden dilatation of +the contracted blood-vessels, are put in vivid and rapid motion, which +causes the painful and tingling sensation that we experience. In every +part of the system, sudden changes produce unpleasant sensations, and +frequently a diseased condition of the organs. + +_Observation._ When the hands, or other portions of the body, are +frozen, or severely chilled, safety and comfort demand that +circulation be restored to the parts by moderate exercise in a cool +room. Not unfrequently, the vitality of the limb is destroyed by +immersing it in hot water or holding it near the fire. + +859. _The quality of the blood also influences sensation._ If the +brain and other parts of the nervous system receive impure blood, +their energy is depressed, and the sensibility of the skin rendered +more or less obtuse. + +860. _The condition of the cuticle modifies the impression made upon +the cutaneous nerves._ 1st. When the cuticle has become thick and +hard, like horn, as on the inside of the mason's hand, it enables him +to ply his tools without much suffering, because the thickened cuticle +diminishes the impressions made upon the nerves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How is it demonstrated? 858. How is the influence of the blood upon +the skin further demonstrated? How should circulation be restored to +limbs frozen or severely chilled? What should be avoided? 859. Show +how the quality of the blood influences sensation. 860. Give the 1st +condition of the cuticle that influences the impressions made on the +cutaneous nerves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +861. 2d. When the cuticle is very thin and delicate, as on the hand of +the lady who is unaccustomed to manual labor. Let her pursue some +manual employment for several hours, and the extreme tenuity, or +thinness of the cuticle, will not protect the nerves and parts below +from becoming irritated and inflamed. + +862. 3d. When the cuticle is removed by blistering or abrasion, the +pain indicates that the naked nerves are too powerfully stimulated by +the contact of external bodies. 4th. When the cuticle is coated with +impurities, blended with the secretion from the oil-glands, the +sensibility of the skin is lessened. + +863. _The sensibility of the cutaneous nerves is modified by being +habituated to impressions._ If, for example, an individual should +immerse his feet in moderately warm water, at first it might induce a +smarting sensation; in a short time, the nerves would not only become +habituated to the warm water, but its warmth night be considerably +increased. The same results follow, if an individual is exposed to a +cold element. The impressions at first are highly disagreeable; but as +soon as the nerves become accustomed to the surrounding atmosphere, it +may impart the most agreeable sensations. + +_Illustration._ 1st. Let a person from the tropical regions go to a +colder climate, and the cool mornings of the latter will at first +affect him unpleasantly; but, after a few days' exposure to the cooler +air, the sensation will be far from disagreeable. + +2d. Let a person enter a room moderately heated; gradually increase +the temperature, until it attains extreme summer heat; not only the +cutaneous nerves, but the whole system, become habituated to the high +temperature. From these facts we learn that the sensations, are not +always a correct index of the real temperature. A well-adjusted +thermometer will indicate it with unerring certainty. + + -=-=-=-=-=-=-=-=-=-=-=-= + +861. The 2d condition. 862. The 3d and 4th condition. 863. Show how +habit influences the sensibility of the cutaneous nerves. Give +illustration 1st. Illustration 2d. + + -=-=-=-=-=-=-=-=-=-=-=-= + +864. _Touch is modified, in a high degree, by education._ Thus the +blind, whose "windows of the soul" are closed to the beauties of the +external world, cultivate this sense to such a degree that they can +distinguish objects with great accuracy. And the rapidity with which +they read books prepared for their use, is a convincing proof of the +niceness and extent to which the cultivation of this sense can be +carried. + +_Illustrations._ 1st. The cloth-dresser, by the aid of this sense, +distinguishes the quality, as well as the slightest difference of +texture, in the different pieces of cloth. + +2d. The miller, from a similar education, quickly detects the quality +of flour or meal, by permitting it to pass between his fingers. The +difference in the texture of cloths, or the quality of the flour, +would not be distinguished by an individual whose tactile sense had +not been trained to make nice comparisons. + + -=-=-=-=-=-=-=-=-=-=-=-= + +864. Is this sense susceptible of improvement? What persons cultivate +it to a high degree? Give illustration 1st. Illustration 2d. + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLII. + +SENSE OF TASTE. + + +865. The chief organ of TASTE is the upper surface of the tongue; +though the lips, the palate, the internal surface of the cheeks, and +the upper part of the oesophagus, participate in this function. + + +ANATOMY OF THE ORGANS OF TASTE. + +866. The tongue is a double organ, composed chiefly of muscular +fibres, which run in almost every direction. The two sides are so +perfectly distinct, that sometimes, in paralysis, one side is +affected, while the function of the other remains perfect. It +possesses great versatility of motion, and can be moulded into a great +variety of shapes. In articulation, mastication, and deglutition, the +tongue is an auxiliary to other organs. + +867. This organ is abundantly supplied with blood-vessels, having a +large artery sent to each side of it. It is also very largely +furnished with nerves; it receives nervous filaments from the fifth, +ninth, and twelfth pairs of nerves. The branch of the fifth, called +the gustatory, is the nerve of taste and sensibility;[21] the +twelfth, called the hypo-glossal, of voluntary motion. By means of the +ninth, called the glosso-pharyngeal the tongue is brought into +association with the fauces, oesophagus, and larynx. It is of obvious +importance that these parts should act in concert; and this is +effected by the distribution of this nerve. + + [21] Some physiologists impute the sense of taste to the ninth pair of + nerves; others, to the twelfth pair; while others, again, + contend that taste is the result of a concurrent action of the + fifth, ninth, and twelfth pairs of nerves. + + -=-=-=-=-=-=-=-=-=-=-=-= + +865. What is the chief organ of taste? What other parts participate in +the function? 866-870. _Give the anatomy of the organs of taste._ 866. +Give the structure of the tongue. 867. Is this organ abundantly +supplied with blood? From what source does the tongue derive its +nerves? + + -=-=-=-=-=-=-=-=-=-=-=-= + +[Illustration: Fig. 134. A view of one side of the neck, showing the +nerves of the tongue. 1, A fragment of the temporal bone. 2, 3, 4, 6, 7, +8, 9, 10, 11, 12, Muscles of the tongue, fauces, and neck. 5, The tongue. +13, The common carotid artery. 14, The jugular vein. 15, The external +carotid. 16, The internal carotid. 17, The gustatory branch of the fifth +pair of nerves. 20, The glosso-pharyngeal nerve. 21, The hypo-glossal, or +the muscular nerve of the tongue. 24, The pneumogastric nerve. 25, The +facial nerve.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +868. What is the appearance of the surface of the tongue? Explain fig. +134. + + -=-=-=-=-=-=-=-=-=-=-=-= + +868. The surface of the tongue is thickly studded with fine papillae, +or _vil'li_, which give the organ a velvety appearance. These papillae +are of three varieties. The first is situated near the base of the +tongue. They belong to the class of mucous follicles. They are larger +than the others, and are called _len-tic'u-lar_, from being shaped +like a lens. These, together with the tonsils, (sometimes called the +almonds of the ears,) secrete mucus, to lubricate the food in the act +of deglutition. + +869. The instruments of taste are the two other sets of papillae. One +set consists of small, oval-shaped bodies, which are scattered over +the whole surface of the tongue. They give it a rough appearance, and +are called the _fil'i-form_ papillae. + +870. The other set of papillae is called the _fun'gi-form_. They are +larger than the former, and consist of small, rounded heads, supported +on short stalks, something in the shape of mushrooms, from which they +derive their name. In the last two described sets of sensitive +papillae, the gustatory branch of the fifth pair of nerves ramifies. + +_Observation._ By applying strong acids, as vinegar, to the tongue, +with a hair pencil, these points will become curiously lengthened. + + +PHYSIOLOGY OF THE ORGANS OF TASTE. + +871. TASTE is the sense which makes us acquainted with the savor of +substances. When fluids are taken into the mouth, the papillae dilate +and erect themselves, and the particular impression excited is +transmitted to the brain through filaments of the gustatory nerve. +This sense is closely connected with that of smell. The pleasures +derived from it are strictly sensual and corporeal, and contribute in +no way to the expansion of the mind, like those of hearing and +seeing. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How many varieties of papillae? Describe the first variety. What is the +function of the lenticular papillae? 869. Describe the filiform +papillae. 870. The fungiform papillae? What nerve ramifies in the +fungiform papillae? How can these papillae, or points, be seen? 871-875. +_Give the physiology of the organs of taste._ 871. Define taste. + + -=-=-=-=-=-=-=-=-=-=-=-= + +872. If dry, solid food is taken, the tongue carries it to the back +side of the mouth, where it receives secretions from the salivary +glands; the saliva, becoming impregnated with its flavor, flows over +the sides of the tongue, and gives to the papillae a perception of the +savory juice; this impression is then communicated to the brain. + +_Observation._ It is supposed that the salts which enter into the +composition of the saliva, are very efficient agents in reducing +substances to a proper state for making impressions on the nerves of +taste. The fact that metals impart a peculiar taste, is owing to a +galvanic shock, and not properly to what we understand by taste. + +873. The primary use of taste is to guide animals in the selection of +food, and to warn them against the introduction of noxious articles +into the stomach. In all the inferior animals, we see that the +original design of taste is still answered. But in man, this sense has +been so abused and perverted, by the introduction of stimulants and +condiments, and the endless admixture of different articles of food, +that the simple action of this part seems to have been superseded +almost entirely by acquired taste. + +874. In children, this sense is usually acute, and their preference is +for food of the mildest character. And it is also true, that every +person has some peculiarities of taste, or dislikes to particular +articles of food. This may be either constitutional or from the +influence of association. + + -=-=-=-=-=-=-=-=-=-=-=-= + +With what sense is this closely connected? What is said of this sense? +872. Give the process by which we taste substances. How can we account +for the taste of metals when applied to the tongue? 873. What is the +primary use of taste? Where do we see it perverted? 874. How is this +sense in children? What is true of every person in reference to +taste? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ This sense has been made to vary more than any other by +the refinements of social life. Thus, the Indian's like or dislike to +particular kinds of food, generally extends to every person of the +same tribe; but among civilized men, no two individuals can be found +alike in all their tastes. + +875. This sense is modified by habit, and not unfrequently those +articles, which at first were disgusting, become highly agreeable by +persevering in the use of them. By cultivation, this sense may be made +very acute. Those persons whose business leads them to judge of the +quality of an article by their taste, can discriminate shades of +flavor not perceivable by ordinary persons. Epicures, and tasters of +wines and teas, afford examples. + +_Observation._ Many persons impair their taste by bad habits, as +chewing and smoking tobacco, and using stimulating drinks, and pungent +condiments with the food. These indulgences lessen the sensibility of +the nerve, and destroy the natural relish for food. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is true of the Indian? 875. Is this sense modified by habit? Give +instances. How is this sense sometimes impaired? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLIII. + +SENSE OF SMELL. + + +876. This sense is located in the air-passages of the _Nose_. To +understand the function of smell, the structure of the nose and nasal +cavities, with the distribution of the olfactory nerves, must be first +examined. + + +ANATOMY OF THE ORGANS OF SMELL. + +877. The NOSE is composed of the _Bones_, _Fi'bro-car'tilages_, and +_Mu'cous Mem'brane_, together with its integuments. + +878. The BONES of the nose are the nasal, and the nasal processes of +the upper jaw. + +879. The FIBRO-CARTILAGES give form and stability to the framework of +the nose, providing at the same time, by their elasticity, against +injuries. They are five in number. + +880. The MUCOUS MEMBRANE, which lines the interior of the nose, is +continuous with the skin externally, and with the lining membrane of +the parts of the throat. The entrance of the nostrils is provided with +numerous hairs, which serve as guardians to the delicate membrane of +the nose. + +881. The NASAL FOSSAE, or nostrils, are two irregular, compressed +cavities, extending from the nose to the pharynx. These cavities are +bounded superiorly by the sphenoid and ethmoid bones; inferiorly, by +the hard palate. In the middle line they are separated from each other +by a bony and fibro-cartilaginous septum; upon the outer wall of each +fossa, in the dried skull, are three projecting processes, termed +spongy bones. In the fresh fossa, these are covered by a mucous +membrane. + + -=-=-=-=-=-=-=-=-=-=-=-= + +876. Where is the sense of smell located? 877-884. _Give the anatomy +of the organs of smell._ 877. Name the parts that enter into the +structure of the nose? 878. What bones form the framework of the nose? +879. What is the use of the cartilages? 880. What relation has the +mucous membrane with other membranes of the nose? 881. Describe the +nasal cavities. + + -=-=-=-=-=-=-=-=-=-=-=-= + +882. The space that intervenes between the superior and middle spongy +bone, is called the _superior me-a'tus_, or channel; the space between +the middle and inferior bone, is the _middle meatus_; and that between +the inferior bone and the floor of the fossa, is the _inferior +meatus_. + +[Illustration: Fig. 135. A vertical section of the middle part of the +nasal cavities. 7, The middle spongy bones. 8, The superior part of the +nasal cavities. 10, The inferior spongy bones. 11, The vomer. 12, The +upper jaw. 13. The middle channel of the nose. 14, The lower channel of +the nose. 17, The palatine process of the upper jaw-bone. 18, The roof of +the mouth covered by mucous membrane. 19, A section of this membrane.] + +883. The MEATUSES are passages that extend backward, from the +nostrils, into which are several openings. They are lined by a mucous +membrane, called the _pi-tu'i-ta-ry_, or _schneiderian_, from +Schneider, who first showed that the secretion of the nasal fossae +proceeded from the mucous membrane, and not from the brain. + + -=-=-=-=-=-=-=-=-=-=-=-= + +882. What terms are applied to the spaces between these processes? +What does fig. 135 represent? 883. Define the meatuses. By what are +they lined? + + -=-=-=-=-=-=-=-=-=-=-=-= + +884. Upon the mucous membrane of the nasal passages, the olfactory +nerve ramifies, and also a branch of the fifth pair of nerves. This +membrane is of considerable extent in man; and in those animals whose +sense of smell is very acute, it is still more extensive. + +[Illustration: Fig. 136. A side view of the passage of the nostrils, and +the distribution of the olfactory nerve. 4, The olfactory nerve. 5, The +fine and curious divisions of this nerve on the membrane of the nose. 6, +A branch of the fifth pair of nerves.] + + +PHYSIOLOGY OF THE ORGANS OF SMELL. + +885. The sense of smell enables us to discern the odor or scent of any +thing. When substances are presented to the nose, the air that is +passing through the nostrils brings the odoriferous particles of +matter in contact with the filaments of the olfactory nerves, that are +spread upon the membrane that lines the air-passages, and the +impression is then transmitted to the brain. + + -=-=-=-=-=-=-=-=-=-=-=-= + +884. What nerves ramify upon this membrane? What is represented by +fig. 136? 885-899. _Give the physiology of the organs of smell._ 885. +How does the mind become sensible of odoriferous particles? + + -=-=-=-=-=-=-=-=-=-=-=-= + +886. This sense, with that of taste, aids man as well as the inferior +animals, in selecting proper food, and it also gives us pleasure by +the inhalation of agreeable odors. The sense of smell, like that of +taste and touch, may be improved by cultivation. It likewise varies in +different persons. + +_Observation._ Sometimes this sense seems to possess a morbid degree +of acuteness in respect to odors, which is highly inconvenient and +even dangerous. With some individuals, the smell of certain fruits, +flowers, cheese, &c., produce nausea and even convulsions. + +887. In the inferior animals generally, the sense of smell is more +acute than in man. Thus the bloodhound will track the hare over +the ground for miles, guided only by the odor that it leaves in +its flight. He also traces the progress of his master through +thickly-crowded streets, distinguishing his footsteps from those of +a thousand others, and amidst the odorous particles emanating from a +thousand sources. + +_Observation._ In some of the higher orders of the inferior animals, +there is an astonishing acuteness of smell in regard to effluvia that +come from living animals. To these animals, it possesses an importance +in them far beyond what it has in man, by making them acquainted with +the presence of their enemies or their prey, when the eye and ear are +incapable of acting. It is related by travellers in Africa, that they +were always apprised of lions in their vicinity during the night, by +the moans and tremblings of their horses. + +888. Smell is somewhat under the control of the will. That is, we +have the power of receiving or rejecting odors that are presented; +thus, if odors are agreeable, we inspire forcibly, to enjoy them; but, +if they are offensive, our inspirations are more cautious, or we close +our nostrils. This sense is likewise modified by habit; odors which, +in the first instance, were very offensive, may not only become +endurable, but even agreeable. + + -=-=-=-=-=-=-=-=-=-=-=-= + +886. What is the use of the sense of smell? Can this sense be +improved by cultivation? What is said respecting this sense in some +individuals? 887. What is said of this sense in the bloodhound? +Mention an instance of astonishing acuteness of smell in some of +the higher orders of animals. 888. Show that smell is somewhat under +the control of the will. + + -=-=-=-=-=-=-=-=-=-=-=-= + +889. Acuteness of smell requires that the brain and nerve of smell be +healthy, and that the membrane that lines the nose be thin and moist. +Any influence that diminishes the sensibility of the nerves, thickens +the membrane, or renders it dry, impairs this sense. + +_Observations._ 1st. _Snuff_, when introduced into the nose, not only +diminishes the sensibility of the nervous filaments, but thickens the +lining membrane. This thickening of the membrane obstructs the passage +of air through the nostrils, and thus obliges "snuff-takers" to open +their mouths when they breathe. + +2d. The mucous membrane of the nasal passages is the seat of chronic +catarrh. This affection is difficult of removal, as remedial agents +cannot easily be introduced into the windings of these passages. Snuff +and many other articles used for catarrh, produce more disease than +they remove. + + -=-=-=-=-=-=-=-=-=-=-=-= + +889. On what does acuteness of smell depend? What effect has snuff +when introduced into the nose? What is said of chronic catarrh? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLIV. + +SENSE OF VISION. + + +890. This sense contributes more to the enjoyment and happiness of man +than any other of the senses. By it we perceive the form, color, +volume, and position of objects that surround us. The eye is the organ +of sight, or vision, and its mechanism is so wonderful, that it not +only proves the existence of a great First Cause, but perhaps, more +than other organs, the design of the Creator to mingle pleasure with +our existence. + + +ANATOMY OF THE ORGANS OF VISION. + +891. The apparatus of vision consists of the _Op'tic Nerve_, the +_Globe_ and _Muscles_ of the eye, and its _Protecting Organs_. + +892. The OPTIC NERVE arises by two roots from the central portion of +the base of the brain. The two nerves approach each other, as they +proceed forward, and some of the fibres of each cross to the nerve of +the opposite side. They then diverge, and enter the globe of the eyes +at their back part, where they expand, and form a soft, whitish +membrane. + +893. The GLOBE, or ball of the eye, is an optical instrument of the +most perfect construction. The sides of the globes are composed of +_Coats_, or membranes. The interior of the globe is filled with +refracting _Humors_, or _me'di-ums_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +890. Which sense contributes most to the enjoyment of man? What do we +perceive by this sense? What is said of the mechanism of the eye? +891-916. _Give the anatomy of the organs of vision._ 891. Of what does +the apparatus of vision consist? 892. Describe the optic nerve. 893. +Describe the globe of the eye. + + -=-=-=-=-=-=-=-=-=-=-=-= + +894. The COATS are three in number: 1st. The _Scle-rot'ic_ and +_Corn'e-a_. 2d. The _Cho'roid_, _Iris_, and _Cil'ia-ry processes_. 3d. +The _Ret'i-na_. + +895 The HUMORS are also three in number: 1st. The _A'que-ous_, or +watery. 2d. The _Crys'tal-line_, (lens.) 3d. The _Vit're-ous_, or +glassy. + +[Illustration: Fig. 137. The second pair of nerves. 1, 1, Globe of the +eye: the one on the left is perfect, but that on the right has the +sclerotic and choroid coats removed, to show the retina. 2, The crossing +of the optic nerve. 5, The pons varolii. 6, The medulla oblongata. 7, 8, +9, 10, 11, 12, 13, The origin of several pairs of cranial nerves.] + +896. The SCLEROTIC COAT is a dense, fibrous membrane and invests about +four fifths of the globe of the eye. It gives form to this organ, and +serves for the attachment of the muscles that move the eye in various +directions. This coat, from the brilliancy of its whiteness, is known +by the name of "the white of the eye." Anteriorly, the sclerotic coat +presents a bevelled edge, which receives the cornea in the same way +that a watch-glass is received by the groove in its case. + + -=-=-=-=-=-=-=-=-=-=-=-= + +894. Name the coats of the eye. 895. Name the humors of the eye. +Explain fig. 137. 896. Describe the sclerotic coat. + + -=-=-=-=-=-=-=-=-=-=-=-= + +897. The CORNEA is the transparent projecting layer, that forms the +anterior fifth of the globe of the eye. In form, it is circular, +convexo-concave, and resembles a watch-glass. It is received by its +edge, which is sharp and thin, within the bevelled border of the +sclerotic, to which it is firmly attached. The cornea is composed of +several different layers; its blood-vessels are so small that they +exclude the red particles altogether, and admit nothing but serum. + +898. The CHOROID COAT is a vascular membrane, of a rich chocolate-brown +color upon its external surface, and of a deep black color within. It +is connected, externally, with the sclerotic, by an extremely fine +cellular tissue, and by the passage of nerves and vessels; internally, +it is in contact with the retina. The choroid membrane is composed of +three layers. It secretes upon its internal surface a dark substance, +called _pig-ment'um ni'grum_, which is of great importance in the function +of vision. + +899. The IRIS is so called from its variety of color in different +persons. It forms a partition between the anterior and posterior +chambers of the eye, and is pierced by a circular opening, which is +called the _pu'pil_. It is composed of two layers. The radiating +fibres of the anterior layer converge from the circumference to the +centre. Through the action of these radiating fibres the pupil is +dilated. The circular fibres surround the pupil, and by their action +produce contraction of its area. The posterior layer is of a deep +purple tint, and is called _u-ve'a_, from its resemblance in color to +a ripe grape. + + -=-=-=-=-=-=-=-=-=-=-=-= + +How are this coat and the cornea united? 897. Describe the cornea. +898. What is the color of the external surface of the choroid coat? Of +the internal? How is it connected externally? How internally? What +does this membrane secrete upon its internal surface? 899. Describe +the iris. Of how many layers of fibres is the iris composed? What is +the function of the radiating fibres? Of the circular? + + -=-=-=-=-=-=-=-=-=-=-=-= + +900. The CILIARY PROCESSES consist of a number of triangular folds, +formed, apparently, by the plaiting of the internal layer of the +choroid coat. They are about sixty in number. Their external border is +continuous with the internal layer of the choroid coat. The central +border is free, and rests against the circumference of the crystalline +lens. These processes are covered by a layer of the pigmentum nigrum. + +[Illustration: Fig. 138. A view of the anterior segment of a transverse +section of the globe of the eye, seen from within. 1, The divided edge of +the three coats--sclerotic, choroid, and retina. 2, The pupil. 3, The +iris: the surface presented to view in this section being the uvea. 4, +The ciliary processes. 5, The scalloped anterior border of the retina.] + +901. The RETINA is composed of three layers: The external; middle, or +nervous; and internal, or vascular. The external membrane is extremely +thin, and is seen as a flocculent film, when the eye is suspended in +water. The nervous membrane is the expansion of the optic nerve, and +forms a thin, semi-transparent, bluish-white layer. The vascular +membrane consists of the ramifications of a minute artery and its +accompanying vein. This vascular layer forms distinct sheaths for the +nervous papillae, which constitute the inner surface of the retina. + + -=-=-=-=-=-=-=-=-=-=-=-= + +900. How are the ciliary processes formed? What does fig. 138 exhibit? +901. Of how many layers is the retina composed? Describe the external +layer. The nervous layer. + + -=-=-=-=-=-=-=-=-=-=-=-= + +902. The AQUEOUS HUMOR is situated in the anterior and posterior +chambers of the eye. It is an albuminous fluid, having an alkaline +reaction. Its specific gravity is a very little greater than distilled +water. The anterior chamber is the space intervening between the +cornea, in front, and the iris and pupil, behind. The posterior +chamber is the narrow space, less than half a line in depth, bounded +by the posterior surface of the iris and pupil, in front, and by the +ciliary processes and crystalline lens, behind. The two chambers are +lined by a thin layer, the secreting membrane of the aqueous humor. + +903. The CRYSTALLINE HUMOR, or lens, is situated immediately behind +the pupil, and is surrounded by the ciliary processes. This humor is +more convex on the posterior than on the anterior surface, and, in +different portions of the surface of each, the convexity varies from +their oval character. It is imbedded in the anterior part of the +vitreous humor, from which it is separated by a thin membrane, and is +invested by a transparent elastic membrane, called the capsule of the +lens. The lens consists of concentric layers, disposed like the coats +of an onion. The external layer is soft, and each successive one +increases in firmness until the central layer forms a hardened +nucleus. These layers are best demonstrated by boiling, or by +immersion in alcohol, when they separate easily from each other. + +_Observations._ 1st. The lens in the eye of a fish is round, like a +globe, and has the same appearance, when boiled, as the lens of the +human eye. + + -=-=-=-=-=-=-=-=-=-=-=-= + +The vascular layer. 902. Where is the aqueous humor situated? What +part of the eye is called the anterior chamber? The posterior chamber? +With what are the chambers lined? 903. Where is the crystalline humor +situated? With what is it surrounded? Of what does the lens consist? +How are these layers best demonstrated? What is produced when the +lens, or its investing membrane, is changed in structure? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. When the crystalline lens, or its investing membrane, is changed +in structure, so as to prevent the rays of light passing to the +retina, the affection is called a _cataract_. + +[Illustration: Fig. 139. A section of the globe of the eye. 1, The +sclerotic coat. 2, The cornea (This connects with the sclerotic coat by a +bevelled edge.) 3, The choroid coat. 6, 6, The iris. 7, The pupil. 8, The +retina. 10, 11, 11, Chambers of the eye that contain the aqueous humor. +12, The crystalline lens. 13, The vitreous humor. 15, The optic nerve. +16, The central artery of the eye.] + +904. The VITREOUS HUMOR forms the principal bulk of the globe of the +eye. It is an albuminous fluid, resembling the aqueous humor, but is +more dense, and differs from the aqueous in this important particular, +that it has not the power of re-producing itself. If by accident it is +discharged, the eye is irrecoverably lost; while the aqueous humor may +be let out, and will be again restored. It is enclosed in a delicate +membrane, called the _hy'a-loid_, which sends processes into the +interior of the globe of the eye, forming the cells in which the humor +is retained. + + -=-=-=-=-=-=-=-=-=-=-=-= + +904. Describe the vitreous humor. How does this humor differ from the +aqueous? What membrane encloses the vitreous humor? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ The structure of this organ can be seen by first +freezing the eye of a sheep or an ox; it then can be cut in various +directions, and each part separately examined. + +905. The MUSCLES of the eye are six in number. They are attached, at +one extremity, to the bones of the orbit behind the eye; at the other +extremity, they are inserted by broad, thin tendons, near the junction +of the cornea with the sclerotic coat. The white, pearly appearance of +the eye is caused by these tendons. + +[Illustration: Fig. 140. A view of the eye and its muscles. _a_, _b_, +_c_, _d_, _e_, Five of these muscles. _f_, The optic nerve. G, The +trochlea, or pulley over which one of the muscles passes. The bone is +seen above and below the eye.] + +_Observation._ If the external muscle is too short, the eye is turned +out, producing the "wall eye." If the internal muscle is contracted, +the eye is turned inward toward the nose. It is then called a "cross +eye." + + -=-=-=-=-=-=-=-=-=-=-=-= + +905. How many muscles has the eye? Give their attachments. What causes +the pearly appearance of the eye? What does fig. 140 represent? What +is the effect if the external muscle is contracted? The internal +muscle? + + -=-=-=-=-=-=-=-=-=-=-=-= + +906. The PROTECTING ORGANS are the _Or'bits_, _Eyebrows_, _Eyelids_, +and _Lach'ry-mal Apparatus_. + +907. The ORBITS are deep, bony sockets, in which the globes of the +eyes are situated. They have the form of a cone, the base of which is +open and directed forward. The bottom of the orbits is pierced by a +large hole which gives passage to the optic nerve. These cavities are +lined with a thick cushion of fat, in order that the eyes may move in +all directions, with perfect freedom and without friction. + +908. The EYEBROWS are two projecting arches of integument, covered +with short, thick hairs, which form the upper boundary of the orbits. +The eyebrows are so arranged that they prevent the moisture that +accumulates on the forehead, in free perspiration, from flowing into +the eye, and also shade these organs from too vivid light. + +909. The EYELIDS are two movable curtains placed in front of the eye. +They have a delicate skin on the outside, muscular fibres beneath, and +a narrow cartilage on their edges, which tends to preserve the shape +of the lid. Internally, they are lined by a smooth membrane, which is +reflected over the front of the eye upon the sclerotica. This membrane +is called the _con-junc-ti'va_. It secretes the fluid that moistens +and lubricates the eye, and which causes the eyelids to open and shut +without friction. + +_Observation._ When the portion of this membrane that is reflected +over the globe of the eye, is inflamed, there is frequently a +deposition of whitish material, called lymph. This accounts for the +films, opacities, and white spots seen upon the eye after the +inflammation has subsided. + + -=-=-=-=-=-=-=-=-=-=-=-= + +906. Name the protecting organs of the eye. 907. Describe the orbits. +How are the movements of the eye facilitated? 908. Describe the +eyebrows. What does this arrangement prevent? 909. Describe the +eyelids. What is the use of the conjunctiva? How are the white spots +frequently seen upon the eye accounted for? + + -=-=-=-=-=-=-=-=-=-=-=-= + +910. There are found several small glands on the internal surface of +the cartilage, which have the appearance of parallel strings of +pearls. They open by minute apertures upon the edges of the lids. The +secretion from these glands prevents the edges of the eyelids from +being united during sleep. + +911. The edges of the eyelids are furnished with a triple row of long, +thick hairs, called _eyelashes_, which curve upward from the upper +lid, and downward from the lower, so that they may not interlace with +each other in the closure of the eyelids. These appendages of the eye, +by closing, not only protect it from moisture, but from dust, +particularly during sleep. They likewise, by their movements in +opening and shutting, spread the lubricating fluid equally over the +eye. + +912. The LACHRYMAL APPARATUS, which secretes the tears, consists of +the _Lachrymal Gland_ with its ducts, _Lachrymal Canals_, and the +_Nasal Duct_. + +913. The LACHRYMAL GLAND is situated at the upper and outer angle of +the orbit. It is about three quarters of an inch in length, flattened +and oval in shape, and occupies a depression in the orbital plate of +the frontal bone. Ten or twelve small ducts pass from this gland, and +open upon the upper eyelid, where they pour upon the conjunctiva the +lachrymal fluid, or tears. This secretion is maintained while we are +asleep, as well as when we are awake. The eye from this cause is kept +constantly moist. + +914. The LACHRYMAL CANALS commence at minute openings upon the free +borders of each eyelid, near the internal angle of the eye, by two +small orifices, called _punc'ta lach-ry-ma'li-a_, (tear points.) Each +of these points communicate with the sac at the upper part of the +nasal duct. + + -=-=-=-=-=-=-=-=-=-=-=-= + +910. What are found on the internal surface of the cartilage of the +eyelids? Where do they open, and what is their use? 911. With what are +the edges of the eyelids furnished? What are their uses? 912. Of what +does the lachrymal apparatus consist? 913. Describe the lachrymal +gland. How many ducts pass from this gland, and what do they convey to +the eye? Why is the eye constantly moist? 914. Where do the lachrymal +canals commence? + + -=-=-=-=-=-=-=-=-=-=-=-= + +915. The NASAL DUCT is a short canal, about three quarters of an inch +in length, directed downward and backward to the inferior channel of +the nose, where it terminates by an expanded orifice. + +[Illustration: Fig. 141. 1, The lachrymal gland. 2, Ducts leading from +the lachrymal gland to the upper eyelid. 3, 3, The puncta lachrymalia. 4, +The nasal sac. 5, The termination of the nasal duct.] + +916. The fluid (tears) secreted by the lachrymal gland, is conveyed to +the eye by the small ducts before described. It is then imbibed by the +puncta lachrymalia, and carried by the lachrymal canals into the +lachrymal sac, from which it is passed to the nasal cavities by the +nasal ducts. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What are they called? With what do they communicate? 915. Describe the +nasal duct. 916. How are the tears conveyed from the lachrymal gland +to the nose? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLV. + +PHYSIOLOGY OF THE ORGANS OF VISION. + + +917. To comprehend the theory of vision, it is not sufficient to know +the structure of the eye. We must be familiar with some of the +properties of a subtile fluid, which is constantly emanating from all +luminous bodies, called _light_. + +918. It is the province of natural philosophy, rather than physiology, +to enter minutely upon the properties of light. It may be observed, +however, that, when light passes through any medium of the same +density, the rays are in straight lines; but, when it passes from one +medium into another of different density, it is refracted, or +turned from a straight course, unless it strikes the medium in a +perpendicular direction--then light passes through without a change +of direction. + +919. When a ray of light meets with a body, it either passes through +it, or is reflected by it, or it may be absorbed. Again, in proportion +as the rays of light become distant from the body from which they +emanate, they diverge one from the other. In accordance with the laws +of optics, the rays of light, in passing through an optical instrument +like the eye, must cross each other, and thus produce an inverted +image of the object from which the rays proceed. With the general +view of the structure of the eye, we will now examine the use of each +part in the function of vision. + + -=-=-=-=-=-=-=-=-=-=-=-= + +917-933. _Give the physiology of the organs of vision._ 917. What is +necessary in order to understand the theory of vision? 918. When light +passes through a medium of the same density, in what direction will be +its rays? Of a different density? What exception? 919. When light +meets with a body, what takes place? What is said in reference to rays +of light in passing through the eye? + + -=-=-=-=-=-=-=-=-=-=-=-= + +920. The sclerotic coat not only gives form to the body of the eye, +but protection to the interior and more delicate parts. The choroid +coat seems to be chiefly composed of a tissue of nerves and minute +blood-vessels; the latter give nourishment to the different parts of +the eye. One of the uses of this coat is, to absorb the rays of light +immediately after they have passed through the retina. This is +effected by the black pigment that lines its inner surface. Were it +not for this provision, light would be too intense, and vision +indistinct. + +_Observation._ In albinos, where there is an absence of the black +pigment, the rays of light traverse the iris, and even the choroid +coat, and so overwhelm the eye with light, that their vision is quite +imperfect, except in the dimness of evening, or at night. In the +manufacture of optical instruments, care is taken to color their +interior black, for the same object, namely, the absorption of +scattered rays. + +921. The iris, by means of its powers of expansion and contraction, +regulates the quantity of light admitted through the pupil. If the +iris is thin, and the rays of light pass through its substance, they +are immediately absorbed by the uvea, and, if that layer be +insufficient, they are taken up by the black pigment of the choroid +coat. + +_Observation._ When we look toward the bottom of the eye, the pupil +appears like a black spot, instead of an opening. This is caused by +seeing the black pigment through the retina and humors of the eye. + + -=-=-=-=-=-=-=-=-=-=-=-= + +920. What is the use of the sclerotic coat? Of what is the choroid +coat chiefly composed? What is the use of this coat? How is it +effected? What is said of albinos? What care is taken in the +manufacture of optical instruments? 921. What is the use of the iris? +When we look toward the bottom of the eye, why does the pupil look +like a black spot, instead of an opening? + + -=-=-=-=-=-=-=-=-=-=-=-= + +922. The cornea, and the aqueous, crystalline, and vitreous humors, +are transparent; so that rays of light traverse these parts of the +eye, and fall upon the retina. The office of these humors and the +cornea is to refract the rays of light in such proportion as to direct +the image in the most favorable manner upon the retina. + +923. The office of the retina is to receive the impression of the rays +of light which leave an object at which we look, and it is upon it +that a small but very clear image of that object is formed. The +impression thus produced by the reflected light is transmitted by the +optic nerve to the brain, which receives the sensation. This +constitutes vision. + +924. The optic nerve has but one function, that of sight. Sensibility +is conferred on this organ by a large branch from the fifth pair of +nerves, which ramifies upon the different parts of the eye and its +appendages. These parts, however, receive some nervous filaments from +the seventh pair. + +_Observations._ 1st. The large number of sensitive nervous filaments +renders the visual organ very impressible to bodies that cause +irritation, as dust, or intense light. This compels us to use due care +to shield the eye from the influence of agents that would impair or +destroy vision. + +2d. Although particles of dust, when in contact with the delicate +parts of the eye, induce severe pain, yet these parts may be cut in +surgical operations, and the patient's sufferings are not as great as +when an incision is made in the skin to remove a small tumor. + +925. Different degrees of density, as already mentioned, modify the +refractory power of any transparent medium. It is found, on +examination, that the cornea, the vitreous, the crystalline, and the +aqueous humors, have each, severally, various degrees of density: and +that the crystalline lens, at its circumference, is less dense than at +its centre. These circumstances modify the direction of the refraction +of the rays of light, in their passage from the cornea to the retina. + + -=-=-=-=-=-=-=-=-=-=-=-= + +922. What is the use of the cornea, aqueous, crystalline, and +vitreous humors? 923. What is the office of the retina? 924. What is +the function of the optic nerve? How is sensibility conferred on +this organ? Give the 1st observation in this connection. The 2d +observation. + + -=-=-=-=-=-=-=-=-=-=-=-= + +926. The refracting powers of the plane, convex, concave, plano-convex, +plano-concave, and concavo-convex lenses,[22] are different. The +cornea and aqueous humors are convexo-concave, the vitreous humor is +concavo-convex, while the crystalline humor is a convexo-convex medium. +(Fig. 139.) + + [22] The refracting character of differently-formed lenses is + illustrated in the works on Natural Philosophy, to which the + pupil is referred. + +[Illustration: Fig. 142. The forms of the different lenses. 1, A plane +lens. 2, A globe lens. 3, A convexo-convex lens. 4, A plano-convex lens. +5, A concavo-concave lens. 6, A plano-concave lens. 7, Meniscus. 8, A +concavo-convex lens.] + + -=-=-=-=-=-=-=-=-=-=-=-= + +925. Have the cornea and the humors of the eye different degrees of +density? What is said of the crystalline lens? What effect has the +different density of the parts of the eye upon the light admitted to +this organ? 926. What kind of lenses do the humors exhibit? 927. What +modifies the refracting powers of transparent mediums? How does this +principle apply to the humors of the eye? + + -=-=-=-=-=-=-=-=-=-=-=-= + +927. The different degrees of convexity or concavity also modify the +refracting character of transparent mediums. The crystalline lens is +of different degrees of convexity on its two sides. The convex +surfaces of the aqueous and vitreous humors are segments of circles, +of different diameters from their concave surfaces. (Fig. 139.) All +these circumstances still further influence the refracting character +of the visual organ. The achromatic arrangement of the transparent +refracting mediums of the eye, remedies the aberration of refraction +in the different portions of the eye. + +928. Again, the refracting power of lenses is modified by their +convexity or concavity. The more convex a lens is, the shorter the +distance from the refracting medium, where the different refracted +rays converge to a focus. To adapt the eye to view objects at +different distances, requires a change in the refracting power of some +of the transparent mediums of the eye. + +929. Both surfaces of the crystalline lens are oval, not spherical, +and the refraction of the rays of light is mainly effected in this +portion of the eye. Change the inclination of this lens, so that +different portions of its anterior surface shall be directly behind +the pupil, and its refracting power is increased or diminished, as the +surface presented is more or less convex. + +930. To view objects at a distance, a less convex lens is needed than +in examining articles very near the eye; and this organ, from its +structure, has the power of adaptation to different distances. It is +supposed that the muscular substance of the ciliary body and processes +changes, by its contraction, the inclination of the crystalline lens. +Without this, or some other adapting power, a picture of objects at +different distances would not be formed upon the retina, and the +vision of every person would be defective, except in reference to +objects at certain definite distances from the eye. + + -=-=-=-=-=-=-=-=-=-=-=-= + +928. What modifies the refracting power of lenses? What is necessary +to adapt the eye to view objects at different distances? 929. Where is +the refraction of the rays of light mainly effected? 930. When we view +objects at a distance, what kind of lens is required? Has the eye the +power of adapting itself to different distances? How is it effected? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ It is well known that a separate image is formed on +each eye, and, if they are not in the same direction, the objects will +appear double. This is proved by pressing one eye, so that the rays of +light cannot enter it in the same direction as they do in the other; +consequently, the vision is double. + +931. By the action of the muscles of the eye, it is turned in +different directions, so that objects can be examined upon each side, +as well as in front, without turning the body. By the slight or +intense action of the straight muscles, the eye is more or less +compressed, and the form of the globe is changed, together with the +relative positions of the different humors. This modification also +adapts the eye to view objects at different distances. + +[Illustration: Fig. 143. 1, A pen, an inverted image of which is painted +on the retina of the eye, at 2. The image of all objects upon the +expansion of the optic nerve, is inverted by the crossing of the rays of +light from objects as they traverse the pupil.] + +_Observation._ If the eye is fixed for a time on some object which is +distinguished with difficulty, there is a painful sensation, similar +to that experienced by other muscles of the body when used too long. +This is called "straining the eye." + +932. When the refraction of the rays of light is too great, as in +over-convexity of the cornea, or the crystalline lens, or the +vitreous humor, or all of them, the image is formed a little in +front of the retina. Persons thus affected cannot see distinctly, +except at a very short distance. This infirmity is called _near_, or +_short-sightedness_. This defect is in a great measure obviated by +the use of concave glasses, which scatter the luminous rays, and thus +counterbalance the too strong refracting force of the eye. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does fig. 143 represent? 931. Why can we see objects at the side +as well as in front of the eye, without turning the body? What is the +effect when the eye is fixed on an object that is indistinctly seen? + + -=-=-=-=-=-=-=-=-=-=-=-= + +933. When the different parts of the eye are not sufficiently convex, +the image is formed beyond the retina, and thus only distant objects +are distinctly seen. This defect is called _long-sightedness_. The +feebleness in the refracting power of the eye may be caused by +disease; but usually it is a consequence of old age, and is remedied +by wearing spectacles with convex glasses. + + +HYGIENE OF THE ORGANS OF VISION. + +934. _The eye, like other organs of the body, should be used, and then +rested._ If we look intently at an object for a long time, the eye +becomes wearied, and the power of vision diminished. The observance of +this rule is particularly needful to those whose eyes are weak, and +predisposed to inflammation. On the contrary, if the eye is not called +into action, its functions are enfeebled. + +935. _Sudden transitions of light should be avoided._ The iris +enlarges or contracts, as the light that falls upon the eye is faint +or strong; but the change is not instantaneous. Hence the imperfect +vision in passing from a strong to a dim light, and the overwhelming +sensation experienced on emerging from a dimly-lighted apartment to +one brilliantly illuminated. A common cause of _am-aur-o'sis_, or +paralysis of the retina, is, using the eye for a long time in a very +intense light. + + -=-=-=-=-=-=-=-=-=-=-=-= + +932. What is short-sightedness? How is the defect remedied? 933. What +is long-sightedness? How is the defect remedied? 934-942. _Give the +hygiene of the organs of vision._ 934. Do the same principles apply to +the use of the eye as to other organs? What is the effect if the eye +is fixed intently on an object for a long time? What results if the +eye is not called into action? 935. Why should sudden transitions of +light be avoided? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Note._ Let the anatomy and physiology of the eye be reviewed from +figs. 139 and 143, or from anatomical outline plate No. 10. + +936. _Long-continued oblique positions of the eye should be avoided, +when viewing objects._ If the eye is turned obliquely for a long time +in viewing objects, it may produce an unnatural contraction of the +muscle called into action. This contraction of the muscle is termed +_stra-bis'mus_, or cross-eye. The practice of imitating the appearance +of a person thus affected, is injudicious, as the imitation, designed +to be temporary, may become permanent. + +_Observation._ The vision of a "cross-eye" is always defective. In +general, only one eye is called into action, in viewing the object to +which the mind is directed. This defect can be remedied by a surgical +operation, which also corrects the position of the eye. + +937. _Children should be trained to use the eye upon objects at +different distances._ This is necessary, in order that the vision may +be correct when objects at various distances are viewed. Any action +unnatural to the muscles, if frequently repeated, may and will modify +the character and action of the parts so operated upon. If a limb, as +the arm, be kept flexed for a long time, one set of muscles will be +relaxed and elongated, and another will be shortened, and its +contractile power will be increased. The same principle is true of the +eye. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What causes palsy of the retina? 936. Why should we avoid oblique +positions of the eye in viewing objects? What is said of the practice +of imitating persons thus affected? What is said in reference to the +vision of a "cross-eye"? 937. Why should children be trained to use +the eye upon objects at different distances? What is the effect if an +unnatural action of the muscles is frequently repeated? Does the same +principle apply to the eye? + + -=-=-=-=-=-=-=-=-=-=-=-= + +938. In viewing objects very near the eye, the ciliary processes are +called into action to produce a proper inclination of the crystalline +lens, so that the rays of light may be properly refracted to form a +perfect image on the retina. In looking at objects at a great +distance, the ciliary processes are called into a different action, to +produce a different inclination of the lens. Let either of these +actions be repeated, again and again, for weeks and months, and they +will become natural, and the acquired inclination will be permanent. + +939. From the preceding principle, a person becomes short or long +sighted, as the objects to which the eye is usually directed are near +or remote. This is one reason why scholars, watchmakers, and +artisans, who bring minute objects near the eye to examine them, +are short-sighted, and why hunters and sailors, who are habituated +to view objects at a distance, are long-sighted. + +_Observation._ In the management of children, whether in the nursery +or school-room, it is very important that their books, or articles +upon which they may labor, should be held at an appropriate distance +from the eye. Were this attended to by the parent or instructor, we +should not see so many persons with defective vision. + +940. Cleanliness, as well as the health of the eye, require that it be +bathed every morning with pure water, either cold or tepid, +accompanied with as little rubbing or friction as possible. In all +instances, the secretion from the lachrymal glands, that sometimes +collects at the angle of the eye, should be removed, as it contains +saline matter. + +941. When small particles, or dust, get upon the eye, they produce +much inconvenience, which is often increased by harsh attempts to +remove them. The individual should be placed before a strong +light, the lids held open with one hand, or by another person, and +the particles removed with the corner of a fine linen or silk +handkerchief. + + -=-=-=-=-=-=-=-=-=-=-=-= + +938. What is the effect of repeatedly using the eye in one direction? +939. Why are artisans and scholars generally short-sighted? Why are +sailors and hunters long-sighted? How can defective vision in a great +degree be prevented? 940. What reasons are there for bathing the eye? +941. How can dust and other small particles be removed from the eye? + + -=-=-=-=-=-=-=-=-=-=-=-= + +942. Sometimes the substance is concealed under the upper eyelid, and +it may then be exposed by turning back the lid in the following +manner: Take a knitting-needle, or small, slender piece of stick, +which is perfectly smooth, and place it over the upper lid, in contact +with, and just under the edge of the orbit; then, holding it firmly, +seize the eyelashes with the fingers of the disengaged hand, and +gently turn the lid back over the stick or needle. The inner side of +the lid can then be examined, and any substance removed that may have +been there concealed. Too many trials ought not to be made, if +unsuccessful, as much inflammation may be induced; but a surgeon +should be consulted as soon as possible. + +_Observation._ Eyestones ought never to be placed in the eye, as they +often cause more pain and irritation than the evil which they are +intended to remedy. + + -=-=-=-=-=-=-=-=-=-=-=-= + +942. How removed from the upper eyelid? Why should not eyestones be +used? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLVI. + +THE SENSE OF HEARING. + + +943. The sense of hearing is next in importance to that of vision. +Through this sense we are enabled to perceive sounds, that not only +subserve to our comfort and pleasure, but are instrumental in +promoting our intellectual enjoyments. The organ of hearing, or the +ear, is one of the most complicated in the human body. + + +ANATOMY OF THE ORGANS OF HEARING. + +944. The EAR is composed of three parts: 1st. The _External Ear._ 2d. +The _Tym'pan-um_, or middle ear. 3d. The _La'by-rinth_, or internal +ear. + +945. The EXTERNAL EAR is composed of two parts: The _Pin'na_, +(pavilion of the ear,) and the _Me-a'tus Aud-it-o'ri-us Ex-ter'nus_, +(auditory canal.) + +946. The PINNA is a cartilaginous plate which surrounds the entrance +of the auditory canal. It presents many ridges and furrows, arising +from the folds of the cartilage that form it. + +_Observation._ The pinna, in many animals, is movable; in those that +pursue their prey, it is generally directed forward; in timid animals, +as the hare and rabbit, it is directed backward. In man, this part is +but slightly under the control of the will. + + -=-=-=-=-=-=-=-=-=-=-=-= + +943. What is said of the importance of hearing? Is the ear complicated +in its structure? 944-962. _Give the anatomy of the organs of +hearing._ 944. Of how many parts is the ear composed? Name them. 945. +Give the parts of the external ear. 946. Describe the pinna. What is +said in reference to the pinna of many animals? + + -=-=-=-=-=-=-=-=-=-=-=-= + +947. The MEATUS AUDITORIUS is a canal partly cartilaginous, and partly +bony, about an inch in length, which extends inward from the pinna to +the _Mem'bra-na Tym'pan-i_, (drum of the ear.) It is narrower in the +middle than at the extremities. It is lined by an extremely thin pouch +of cuticle, which, when withdrawn, after maceration, preserves the +form of the canal. Some stiff, short hairs are also found in the +interior of the channel, which stretch across the tube, and prevent +the ingress of insects. Beneath the cuticle are a number of small +follicles, which secrete the wax of the ear. + +[Illustration: Fig. 144. A representation of the four bones of the ear. +The smallest is highly magnified. This bone is early matured, and in the +adult it becomes united with the incus. These bones are retained in their +places and moved by three ligaments and four muscles.] + +948. The MEMBRANA TYMPANI is a thin, semi-transparent membrane, of an +oval shape. It is about three eighths of an inch in diameter, and is +inserted into a groove around the circumference of the meatus, near +its termination. This membrane is placed obliquely across the area of +that tube. It is concave toward the meatus, and convex toward the +tympanum. + +949. The TYMPANUM consists of an irregular bony cavity, situated +within the temporal bone. It is bounded externally by the membrana +tympani; internally by its inner wall; and in its circumference by the +petrous portion of the temporal bone and mastoid cells. The tympanum +contains four small bones, called the _os-sic'u-la au-di'tus_. These +are named separately, the _mal'le-us_, _in'cus_, _sta'pes_, and +_or-bic'u-lar_. + + -=-=-=-=-=-=-=-=-=-=-=-= + +947. What is the meatus auditorius? What is found in this canal? What +is their use? Where is the wax of the ear secreted? 948. Describe the +membrana tympani. 949. Where is the tympanum situated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +950. There are ten openings in the middle ear; five large and five +small. The larger openings are, the _Me-a'tus Aud-it-o'ri-us +Ex-ter'nus_, _Fe-nes'tra O-va'lis_, (oval window,) _Fe-nes'tra +Ro-tun'da_, (round window,) _Mas'toid Cells_, and _Eu-sta'chi-an +Tube_. + +[Illustration: Fig. 145. A representation of the pinna, meatus, membrana +tympani, bones of the ear, and semicircular canals. _a_, The pinna. _c_, +The meatus auditorius externus. _g_, The membrana tympani. _k_, The +tympanum. _e_, The bones of the ear. _b_, The semicircular canals. _f_, +The cochlea. _h_, The vestibule. _i_, The Eustachian tube. _d_, The +auditory nerve.] + +951. The FENESTRA OVALIS is the opening of communication between the +tympanum and the vestibule. It is closed by the foot of the stapes, or +bone of the ear, and by the lining membrane of both cavities. + +952. The FENESTRA ROTUNDA serves to establish a communication between +the tympanum and the cochlea. it is closed by a proper membrane, as +well as by the lining of both cavities. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What does this cavity contain? 950. How many openings in the tympanum? +Explain fig. 145. 951. Describe the fenestra ovalis. 952. The fenestra +rotunda. + + -=-=-=-=-=-=-=-=-=-=-=-= + +953. The MASTOID CELLS are very numerous, and occupy the whole of the +interior of the mastoid process of the temporal bone, and part of the +petrous bone. They communicate, by a large, irregular opening, with +the upper and posterior circumference of the tympanum. + +[Illustration: Fig. 146. A view of the labyrinth laid open. This figure +is highly magnified. 1, 1, The cochlea. 2, 3, Two channels, that wind two +and a half turns around a central point, (5.) 7, The central portion of +the labyrinth, (vestibule.) 8, The foramen rotundum. 9, The fenestra +ovalis. 11, 12, 13, 14, 15, 16, 17, 18, The semicircular canals. The +cochlea and semicircular canals open into the vestibule.] + +954. The EUSTACHIAN TUBE is a canal of communication, extending +obliquely between the pharynx and the anterior circumference of the +tympanum. In structure it is partly fibro-cartilaginous and partly +bony. It is broad and expanded at its pharyngeal extremity, and narrow +and compressed at the tympanum. + + -=-=-=-=-=-=-=-=-=-=-=-= + +953. Where are the mastoid cells? Explain fig. 146. 954. Describe the +Eustachian tube. + + -=-=-=-=-=-=-=-=-=-=-=-= + +955. The small openings of the middle ear are for the entrance and +exit of the chorda tympani, (a small nerve that crosses the tympanum,) +and for the exit of the muscles that act upon the membrana tympani and +bones of the ear. + +956. The LABYRINTH consists of a membranous and a bony portion. The +bony labyrinth presents a series of cavities which are channelled +through the substance of the petrous bone. It is situated between the +cavity of the tympanum and the _Aud'it-o-ry Nerve_. The labyrinth is +divided into the _Ves'ti-bule_, _Sem-i-cir'cu-lar Canals_, and +_Coch'le-a_. + +957. The VESTIBULE is a small, three-cornered cavity, situated +immediately within the inner wall of the tympanum. + +958. The SEMICIRCULAR CANALS are three bony passages which communicate +with the vestibule, into which two of them open at both extremities, +and the third at one extremity. + +959. The COCHLEA forms the anterior portion of the labyrinth. It +consists of a bony and gradually tapering canal, about one and a half +inches in length, which makes two turns and a half, spirally, around a +central axis, called the _mo-di'o-lus_. The modiolus is large near its +base, where it corresponds with the first turn of the cochlea, and +diminishes in diameter toward its extremity. + +960. The interior of the canal of the cochlea is partially divided +into two passages, by means of a bony and membranous plate. At the +extremity of the modiolus, the two passages communicate with each +other. At the other extremity, one opens into the vestibule; the other +into the tympanum, by the foramen rotundum. The internal surface of +the bony labyrinth is lined by a fibro-serous membrane. + + -=-=-=-=-=-=-=-=-=-=-=-= + +955. What passes through the small openings of the middle ear? 956. Of +what does the labyrinth consist? Give the parts of the internal ear. +957. Describe the vestibule. 958. What is said of the semicircular +canals? 959. Why is the cochlea so called? Of what does it consist? +960. How is the interior of the canal of the cochlea divided? Where do +they communicate with each other? + + -=-=-=-=-=-=-=-=-=-=-=-= + +961. The membranous labyrinth is smaller in size, but a perfect +counterpart, with respect to form, of the bony vestibule, cochlea, and +semicircular canals. Within this labyrinth are two small, elongated +sacs, which are filled with a fluid. + +[Illustration: Fig. 147. A view of the auditory nerve. 1, The spinal +cord. 2, The medulla oblongata. 3, The lower part of the brain. 4, The +auditory nerve. 5, A branch to the semicircular canals. 6, A branch to +the cochlea.] + +962. The AUDITORY NERVE enters the temporal bone upon its internal +surface, and divides into two branches, at the bottom of the cavity of +the internal ear. These branches enter the structure of the elongated +sacs and membranous labyrinth, radiating in all directions, and +finally, they terminate upon the inner surface of the membrane, in +minute papillae, resembling those of the retina. + + -=-=-=-=-=-=-=-=-=-=-=-= + +By what is the internal labyrinth lined? 961. Describe the membranous +labyrinth. What does fig. 147 represent? 962. Where does the auditory +nerve enter and divide? Where do the branches of the auditory nerve +enter and terminate? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLVII. + +PHYSIOLOGY OF THE ORGANS OF HEARING. + + +963. HEARING is that function by which we obtain a knowledge of the +vibratory motions of bodies, which constitute sounds. The precise +function of all the different parts of the ear is not known. + +964. The function of that part of the external ear which projects from +the head is to collect sounds and reflect them into the meatus. + +965. The membrana tympani serves to facilitate the transmission of +sounds, and also to moderate their intensity. It is so arranged that +it can be relaxed or tightened. + +_Observation._ This membrane, when healthy, has no opening; and it +must be apparent that the apprehension which is often expressed, that +insects will penetrate further, is groundless. The pain is owing to +the extreme sensibility of the membrana tympani. + +966. The supposed office of the tympanum is to transmit the vibrations +made on the membrana tympani to the internal ear. This is effected by +the air which it contains, and by the chain of small bones that are +enclosed in this cavity. + +967. The use of the Eustachian tube is to admit air into the tympanum, +which renders the pressure on both sides equal, and thus its membrane +is kept in a proper state of tension. + + -=-=-=-=-=-=-=-=-=-=-=-= + +963-971. _Give the physiology of the organs of hearing._ 963. What is +hearing? Are the precise functions of the different parts of the ear +known? 964. What is the function of the external ear? 965. Of the +membrana tympani? What observation in reference to this membrane? 966. +What is the supposed office of the middle ear? 967. What is the use of +the Eustachian tube? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Observation._ When near a cannon, or a field-piece, about being +discharged, by opening the mouth the impression upon the auditory +nerve will be diminished, and the unpleasant sensation lessened. This +is the result of the air in the middle ear escaping through the +Eustachian tube, when the vibrations of the membrana tympani are +violent. + +[Illustration: Fig. 148. A view of all the parts of the ear. 1, The tube +that leads to the internal ear. 2, The membrana tympani. 3, 4, 5, The +bones of the ear. 7, The central part of the labyrinth, (vestibule.) 8, +9, 10, The semicircular canals. 11, 12, The channels of the cochlea. 13, +The auditory nerve. 14, The channel from the middle ear to the throat, +(Eustachian tube.)] + +968. But little is known of the functions of the internal ear; its +parts are filled with a watery fluid, in which the filaments of the +auditory nerve terminate. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What observation in this connection? 968. What is the function of the +internal ear? + + -=-=-=-=-=-=-=-=-=-=-=-= + +969. Many of the parts just enumerated aid in hearing, but are not +absolutely essential to this sense. But if the vestibule and auditory +nerve are diseased or destroyed, no sound is then perceived. If this +sense is destroyed in early life, the person also loses the power of +articulating words. Hence a man born deaf is always dumb. + +970. The transmission of sound through the different parts of the ear +will now be explained by aid of fig. 148. The vibrations of air are +collected by the external ear, and conducted through the tube (1) to +the membrana tympani, (2.) From the membrane vibrations pass along the +chain of bones, (3, 4, 5.) The bone 5 communicates with the internal +ear, (7, 8, 9, 10, 11, 11, 11, 12, 12, 12.) From the internal ear the +impression is transmitted to the brain by the nerve, (13.) + +971. The auditory nerve, like the optic, has but one function, that of +special sensibility. The nerves which furnish the ear with ordinary +sensibility, proceed from the fifth pair. + + +HYGIENE OF THE ORGANS OF HEARING. + +972. Hearing, like the other senses, is capable of very great +improvement. By cultivation, the blind are enabled to judge with great +accuracy the distance of bodies in motion, and even the height of +buildings. It is also capable of improvement when all the other senses +are perfect. Thus the Indian will distinguish sounds that are +inaudible to the white man. + + -=-=-=-=-=-=-=-=-=-=-=-= + +969. What parts of the ear are essential in order to hear sounds? What +follows loss of hearing? 971. What is the office of the auditory +nerve? What nerves convey ordinary sensibility to the ear? 972-978. +_Give the hygiene of the organs of hearing._ 972. Is this sense +capable of improvement? How does this sense aid the blind? Is it also +capable of improvement when all the other senses are perfect? In whom +is this illustrated? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Note._ Let the anatomy and physiology of the organs of hearing be +reviewed, from fig. 148, or from anatomical outline plate No. 10. + +973. Acute hearing requires perfection in the structure and functions +of the different parts of the ear, and that portion of the brain from +which the auditory nerve proceeds. Deafness is by no means unfrequent. +We will now advert to some of the common causes of imperfect hearing. + +974. The structure or functional action of the brain may be deranged +by inflammation, by compression, or by debility, and produce deafness. +The first is seen during inflammatory affections of the brain, and in +fevers; the second is seen in accidental injuries of the head; the +third is seen in old age, and after severe diseases of the head, and +fevers. In these cases, applications to, and operations upon, the ear +do no good. The only remedy is to remove, if possible, the diseased +condition of the brain. + +975. Imperfect hearing may be produced by the destruction of the +membrana tympani, or removal of the bones of the ear, or the parts +within the labyrinth. In these instances, medical treatment is of no +avail, as the destroyed parts cannot be restored. + +976. Hearing may be rendered defective by a diminution of the +vibratory character of the membrana tympani. This may result from a +thickening of this membrane, or from an accumulation of wax upon its +outer surface. The increased thickness is usually the result of +inflammation, either acute or chronic. The proper treatment is such as +is efficient to remove inflammatory action. + +_Observations._ 1st. The introduction of heads of pins into the ear is +a frequent cause of chronic inflammation of the membrana tympani. +Hence this practice should never be adopted, and if acquired, should +be abandoned. + + -=-=-=-=-=-=-=-=-=-=-=-= + +973. On what does acute hearing depend? 974. State effects on the +hearing in some conditions of the brain. How relieved? 975. Of the +effect on hearing when the bones of the ear or the labyrinth are +destroyed? Is medical treatment of any avail? 976. What conditions of +the drum of the ear may impair hearing? How relieved? What is said of +the introduction of pins to cleanse the ear? + + -=-=-=-=-=-=-=-=-=-=-=-= + +2d. The accumulations of viscid wax may be softened by dropping some +animal oil into the ear, and then removing it by ejecting warm soap +suds a few hours subsequent to the use of the oil. This may be +repeated for several successive days. + +977. Hearing may be impaired by obstruction of the Eustachian tube. +The closure of this canal diminishes the vibratory character of +the air within the tympanum, in the same manner as closing the +opening in the side of a drum. For the same reason, enlarged +tonsils, inflammation and ulceration of the fauces and nasal +passages during and subsequent to an attack of scarlet fever, and +the inflammation attending the "sore throat" in colds, are common +causes of this obstruction. + +978. The treatment of such cases of defective hearing, is to have the +tonsils, if enlarged, removed by a surgeon; for the inflammation and +thickening of the parts remedial means should be applied, directed by +a skilful physician. The nostrums for the cure of deafness are +generally of an oleaginous character, and may be beneficial in cases +of defective hearing caused by an accumulation of wax upon the drum of +the ear, but in this respect they are no better than the ordinary +animal oils. + + -=-=-=-=-=-=-=-=-=-=-=-= + +What is the remedy where there is an accumulation of wax? 977. What is +the effect on hearing if the Eustachian tube is obstructed? 978. What +is the treatment when deafness is caused by inflammation or ulceration +the fauces? What is said of the nostrums used for deafness? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLVIII + +MEANS OF PRESERVING THE HEALTH.[23] + + [23] It is advised, that a thorough review of the hygiene of the + preceding chapters be given from the suggestions contained in + this. + + +979. Our bodies are constituted in harmony with certain laws, and +every person should learn these, in order to regulate his actions and +the performance of his duties, so that health may be unimpaired, and +the power of enjoyment, activity, and usefulness continue while life +lasts. + +980. It is a law of the bones and the muscles, that they should either +be used in some vocation, or called into action by some social play +and active sport. + +981. All admit that food is necessary to sustain life; and unless it +be of a proper quality, taken in proper quantities, and at proper +times, the functions of the digestive organs will be deranged, and +disease produced. + +982. Pure air is essential to the full enjoyment of health. The impure +air of unventilated rooms may be breathed, and the effect be so +gradual as not to arrest attention; yet it is a violation of the +physical laws, and, sooner or later, we pay the penalty in disease and +suffering. + + -=-=-=-=-=-=-=-=-=-=-=-= + +979. Why is it incumbent on every person to learn the laws of health? +980. Give a law of the muscles. 981. In preserving the health, is it +necessary to give attention to the food which is eaten? Why? 982. What +beside food is essential to the full enjoyment of health? What is said +of the impure air of unventilated rooms? 983. What should be observed +in regard to sleep? + + -=-=-=-=-=-=-=-=-=-=-=-= + +983. The body also requires sleep; and if it is not taken at the right +time, or with regularity, we do not feel full refreshment from "tired +nature's sweet restorer." Let youth be taught that "early to bed and +early to rise" gives him health and its attendant blessings. The +brain, like other organs of the body, should be called into action at +proper times. + +984. From the extent of the surface of the skin, and the close +sympathy that exists between it and those organs whose office is, to +remove the waste particles of matter from the body, it therefore +becomes very important in the preservation of the health, that the +functions of this membrane be properly maintained. + +985. The function of the circulatory and secretory organs, together +with the operations of absorption and nutrition, should be steadily +maintained, as vitality and the generation of animal heat are +intimately connected with these processes. In the proper performance +of these functions, very much depends on the observance of the laws +of the muscular, digestive respiratory, dermoid, and nervous +apparatuses. + + +REMOVAL OF DISEASE. + +986. It is seldom that a physician is called in the first stages of +disease. At this important period, the treatment adopted should be +proper and judicious, or the sufferings of the patient are increased, +and life, to a greater or less degree, is jeopardized. Hence the +utility of knowing what _should be done_, and what _should not be +done_, in order that the health may be rapidly regained. + +987. In all instances of acute disease, it is proper to rest, not only +the body, but the mind. To effect this, the patient should cease from +physical exertion, and also withdraw his thoughts from study and +business operations. This should be done, even if the person is but +slightly indisposed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +984. Why should the functions of the skin be properly maintained? 985. +Show the necessity of maintaining properly other functions of the +system. 986. What is important in the first stages of disease? 987. +What is proper in all instances of acute disease? How can it be +effected? + + -=-=-=-=-=-=-=-=-=-=-=-= + +988. Select a room for a sick person that is exposed to as little +external noise as possible, as impressions made on the organ of +hearing greatly influence the nervous system. Likewise select a +spacious, well-ventilated apartment, that has no superfluous +furniture. The practice of placing a sick person in a small, +ill-arranged sleeping-room, when a more spacious room can be used, is +poor economy, not to say unkind. + +989. Care is necessary in regulating the light of a sick-room. While a +strong light would produce an increased action of the vessels of the +brain, a moderate light would be an appropriate stimulus to this +organ. It is seldom or never necessary to exclude all light from the +sick-chamber. + +990. A sick person, whether a child or an adult, should not be +disturbed by visitors, even if their calls are short. The excitement +of meeting them is followed by a depression of the nervous system. The +more dangerous and apparently nearer death the sick person is, the +more rigorous should be the observance of this suggestion. Nor should +the sick-room be opened to privileged classes; for the excitement +caused by a visit from relations and the virtuous, will do as much +injury to the sick, as that produced by strangers and the vicious. + +991. The custom of visiting and conversing with sick friends during +the intervals of daily labor, and particularly on _Sunday_, is a great +evil. No person will thus intrude herself in the sick-chamber who +cares more for the welfare of the suffering friend than for the +gratification of a _sympathetic curiosity_. Inquiries can be made of +the family respecting the sick, and complimentary or necessary +messages can be communicated through the nurse. + + -=-=-=-=-=-=-=-=-=-=-=-= + +988. What rooms should be selected for the sick? Why? 989. What is +said in reference to the quantity of light admitted into a sick-room? +990. What effect have calls on the sick? 991. What is said of the +custom of calling and conversing with the sick during the intervals of +daily labor? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ While attending a Miss B., of N. H., sick of fever, I +pronounced her better, withdrew medicine, directed a simple, low diet, +and the exclusion of all visitors. In the evening I was sent for to +attend her. There was a violent relapse into the disease, which +continued to increase in severity until the fourth day, when death +terminated her sufferings. I learned that, soon after I gave +directions that no visitors be admitted into her room, several +_particular_ friends were permitted to enter the chamber and talk with +the sick girl. Their conversation produced a severe headache; and, to +use the language of the patient, "it seemed as if their talk would +kill me;" and _it did kill her_. + +992. No _solid food_ should be taken in the first stages of disease, +even if the affection is slight. The thirst can be allayed by drinking +cold water, barley-water, and other preparations of an unstimulating +character. It is wrong to tempt the appetite of a person who is +indisposed. The cessation of a desire for food, is the warning of +nature, that the system is in such a state that it cannot be +digested. + +993. When a patient is recovering from illness, the food should be +simple, and in quantities not so great as to oppress the stomach. It +should also be given with regularity. "Eat little and often," with no +regard to regularity, is a pernicious practice. + +994. When a physician attends a sick person, he should have the +_special_ management of the food, particularly after the medicine has +been withdrawn and the patient is convalescent. The prevailing idea +that _every_ person may safely advise relative to food, or that the +appetite of the convalescing person is a competent guide, is +dangerous; and cannot be too much censured. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give an illustration. 992. What suggestion relative to food in the +first stages of disease? How can the thirst be allayed? 993. When the +patient is convalescent, how should the food be given? What is said of +the practice of eating "little and often"? 994. Who should have the +special management of food when medicine is withdrawn? What idea +prevails in the community? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustration._ In 1832, I attended a Miss M., sick of fever. After an +illness of a few days, the fever abated, and I directed a simple, +unstimulating diet. Business called me from the town two days. During +my absence, a sympathizing, officious matron called; found her weak, +but improving; and told her she needed food to strengthen her; and +that "it would now do her good." Accordingly, eggs and a piece of +beefsteak were prepared, and given to the convalescent girl. She ate +heartily, and the result was a relapse into a fever more violent than +the first attack. + +995. It is very important in disease that _the skin be kept clean_. A +free action of the vessels of this part of the body exerts a great +influence in removing disease from the internal organs, as well as +keeping them in health. If the twenty or thirty ounces of waste, +hurtful matter, that passes through the "pores" of the skin in +twenty-four hours, are not removed by frequent bathing and dry +rubbing, it deranges the action of the vessels that separate this +waste matter from the blood, and thus increases the disease of the +internal organs. + +_Illustration._ Mrs. M. R., of N., Mass., was afflicted with disease +of the lungs and cough. This was accompanied with a dry, inactive +condition of the skin. As medicine had no salutary effect in relieving +her cough, she was induced by the advice of the clergyman of the +parish to enter upon a systematic course of bathing twice every day. +Soon the skin became soft, its proper functions were restored, the +disease of the lungs yielded, and the cough disappeared. + +996. Every sick person should breathe _pure air_. The purer the blood +that courses through the body, the greater the energy of the system +to remove disease. The confined vitiated air of the sick-chamber, not +unfrequently prolongs disease; and in many instances, the affection is +not only aggravated, but, even rendered fatal, by its injurious +influences. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Give an illustration of the evil effects attending such an idea. 995. +Does the skin exert a great influence in removing disease from the +internal organs, as well as in keeping them in health? Give an +illustration 996. Why should every sick person, particularly, breathe +pure air? + + -=-=-=-=-=-=-=-=-=-=-=-= + +_Illustrations._ 1st. In 1833, I was called, in consultation with +another physician, to Mr. H., who was much debilitated, and delirious. +For several successive days he had not slept. His room was kept very +warm and close, for fear he would "take cold." The only change that I +made in the treatment, was to open the door and window, at a distance +from the bed. In a short time, the delirium ceased, and he fell into a +quiet slumber. From this time he rapidly recovered, and the delirium +was probably the result of breathing impure air. + +2d. Formerly, every precaution was used to prevent persons sick of the +small-pox from breathing fresh air. When Mrs. Ramsay had this disease +in Charleston, S.C., her friends, supposing that life was extinct, +caused her body to be removed from the house to an open shed. The pure +air revived the vital spark. The result probably would have been +different, had she been kept a few hours longer in the vitiated air. + +997. The influence of habit should not be disregarded in the removal +of disease. If food or drink is to be administered, however small in +quantity or simple its quality, it should be given at or about the +time when the ordinary meals were taken in health. + +998. Again, the usual time when the patient was in the habit of +retiring for sleep should be observed, and all preparation necessary +for the sick-room during the night should be made previous to this +hour. Efforts should also be made to evacuate the waste matter of the +digestive and urinary organs at the period which habit has formed in +health. This is not only a remedial agent in disease, but often +precludes the necessity of laxative or drastic cathartics. + + -=-=-=-=-=-=-=-=-=-=-=-= + +Are not diseases prolonged, and even rendered fatal, from breathing +the impure, vitiated air of the sick-chamber? Give illustration 1st. +Give illustration 2d. 997. What is said respecting the influence of +habit in removing disease? + + -=-=-=-=-=-=-=-=-=-=-=-= + +999. MEDICINE is sometimes necessary to _assist_ the natural powers of +the system to remove disease; but it is only an _assistant_. While +emetics are occasionally useful in removing food and other articles +from the stomach that would cause disease if suffered to remain, and +cathartics are valuable, in some instances, to relieve the alimentary +canal of irritating residuum, yet the frequent administration of +either will cause serious disease. + +1000. Although medicine is useful in some instances, yet, in a great +proportion of the cases of disease, including fevers and inflammations +of all kinds, attention to the laws of health will tend to relieve the +system from disease; more certainly and speedily, and with less +danger, than when medicines are administered. + +1001. Thomas Jefferson, in writing to Dr. Wistar, of Philadelphia, +said, "I would have the physician learn the limit of his art." I would +say, Have the matrons, and those who are continually advising "herb +teas," and other "cure-alls," for any complaint, labelled with some +popular name, learn the limits of their duty, namely, attention to the +laws of health. The rule of every family, and each individual, should +be, to touch not, taste not of medicine of _any kind_, except when +directed by a well-educated and honest physician, (sudden disease from +accidents excepted.) + + -=-=-=-=-=-=-=-=-=-=-=-= + +999. What is said of the use of medicine? 1000. Of its use in fevers +and many other cases of disease? 1001. What remark by Thomas Jefferson +to Dr. Wistar? What should matrons learn? What should be the rule of +every person in regard to taking medicine? What exception? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +CHAPTER XLIX. + +DIRECTIONS FOR NURSES. + + +1002. The nurse requires knowledge and practice to enable her to +discharge aright her duty to the patient, as much as the physician and +surgeon do to perform what is incumbent on them. Woman, from her +constitution and habits, is the natural nurse of the sick; and, in +general, no small portion of her time is spent in ministering at the +couch of disease and suffering. + +1003. As the young and vigorous, as well as the aged and the infirm, +are liable to be laid upon the bed of sickness, by an epidemic, or +imprudent exposure, or by some accident, it is therefore necessary +that the girl, as well as the matron, may know how she can render +services in an efficient and proper manner. No _girl_ should consider +her education complete who is not acquainted with the principles of +the duties of a general nurse and a temporary watcher. + +1004. It is to be regretted, that while we have medical schools and +colleges to educate physicians, there is no institution to educate +_nurses_ in their equally responsible station. In the absence of such +institutions, the defect can be remedied, to some extent, by teaching +every girl _hygiene_, or _the laws of health_. To make such knowledge +more available and complete, attention is invited to the following +suggestions relative to the practical duties of a nurse. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1002. Does the nurse require knowledge and practice in her employment, +as well as the physician? Who is the natural nurse of the sick? 1003. +What, then, is incumbent on every girl? 1004. Should there be schools +to educate nurses, as well as physicians and surgeons? + + -=-=-=-=-=-=-=-=-=-=-=-= + +1005. BATHING. The nurse, before commencing to bathe the patient, +should provide herself with water, two towels, a sponge, a piece of +soft flannel, and a sheet. The temperature of the room should also be +observed. + +1006. When the patient is feeble, use _tepid_ or warm water. Cold +water should only be used when the system has vigor enough to produce +reaction upon the skin. This is shown by the increased redness of the +skin, and a feeling of warmth and comfort, after a proper amount of +friction. Before using the sponge to bathe, a sheet, or fold of cloth, +should be spread smoothly over the bed, and under the patient, to +prevent the bed-linen on which the patient lies from becoming damp or +wet. + +1007. Apply the wet sponge to one part of the body at a time; as the +arm, for instance. By doing so, the liability of contracting chills is +diminished. Take a dry, soft towel, wipe the bathed part, and follow +this by vigorous rubbing with a crash towel, or, what is better, a +mitten made of this material; then use briskly a piece of soft +flannel, to remove all moisture that may exist on the skin, and +particularly between the fingers and the flections of the joints. In +this manner bathe the entire body. + +1008. The sick should be thoroughly bathed, at least twice in +twenty-four hours. Particular attention should be given to the parts +between the fingers and toes, and about the flections of the joints, +as the accumulation of the excretions is most abundant on these parts. +In bathing, these portions of the system are very generally neglected. +The best time for bathing, is when the patient feels most vigorous, +and freest from exhaustion. The practice of daubing the face and hands +with a towel dipped in hot rum, camphor, and vinegar, does not remove +the impurities, but causes the skin soon to feel dry, hard, and +uncomfortable. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1005. What should a nurse provide herself with, before bathing a +patient? 1006. When should cold water be used? 1007. How should the +bathing then be performed, so that the patient may not contract a +cold? 1008. How often should a sick person be bathed? What is said of +daubing the face and hands merely with a wet cloth? + + -=-=-=-=-=-=-=-=-=-=-=-= + +1009. FOOD. It is the duty of every woman to know how to make the +simple preparations adapted to a low diet, in the most wholesome and +the most palatable way. Water-gruel,[24] which is the simplest of all +preparations, is frequently so ill-made as to cause the patient to +loathe it. Always prepare the food for the sick, in the neatest and +most careful manner. + + [24] Directions for making the simple preparations for the sick are + found in almost every cook-book. + +1010. When the physician enjoins abstinence from food, the nurse +should strictly obey the injunction. She should be as particular to +know the physician's directions about diet, as in knowing how and when +to give the prescribed medicines, and obey them as implicitly. + +1011. When a patient is convalescent, the desire for food is generally +strong, and it often requires firmness and patience, together with +great care, on the part of the nurse, that the food is prepared +suitably, and given at proper times The physician should direct how +frequently it should be taken. + +1012. PURE AIR. It is the duty of the nurse to see that not only the +room is well ventilated in the morning, but that fresh air is +constantly admitted during the day. Great care must be taken, however, +that the patient does not feel the current. + +1013. Bed-linen, as well as that of the body, should be aired every +day, and oftener changed in sickness than in health. All clothing, +when changed, should be well dried, and warmed by a fire previous to +its being put on the patient or the bed. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1009. Should every woman know how to make the simple preparations +adapted to a low diet? 1010. Should the nurse strictly obey the +injunctions of the physician relative to food? 1011. What period of a +person's illness requires the most care in regard to the food? 1012. +Give another duty of the nurse. 1013. What directions respecting the +bed-linen of the patient? What is necessary when there is a change of +clothing? + + -=-=-=-=-=-=-=-=-=-=-=-= + +1014. TEMPERATURE. The warmth of the chamber should be carefully +watched by the nurse. The feelings of the patient or nurse are not to +be relied on as an index of the temperature of the room. There should +be a well-adjusted thermometer in every sick-room. This should be +frequently consulted by the nurse. + +1015. The temperature of the sick-chamber should be _moderate_. If it +is so cold as to cause a chill, the disease will be aggravated. If, on +the other hand, it is too warm, the patient is enfeebled and rendered +more susceptible to cold on leaving the sick-chamber. The Latin maxim, +"_In medio tutissimus ibis_," (in medium there is most safety,) should +be regarded in the rooms of the sick. + +1016. QUIET. The room of the patient should be kept free from noise. +The community should be guided by this rule, that no more persons +remain in the room of the sick, than the welfare of the patient +demands. It is the duty of the physician to direct when visitors can +be admitted or excluded from the sick-room, and the nurse should see +that these directions are enforced. + +1017. The movements of the attendants should be gentle and noiseless. +Shutting doors violently, creaking hinges, and all unnecessary noise, +should be avoided. Most persons refrain from loud talking in the sick +chamber, but are not equally careful to abstain from _whispering_, +which is often more trying than a common tone. + +1018. It is the duty of the nurse to ascertain the habits of the +patient as respects the period for eating and sleep, when in health, +that she may prepare the food and arrange the sick-room in accordance +with the practice of the patient. If the person who is sick is +ignorant of the necessity of the removal of the waste products from +the system the nurse should invite attention to these functions at +such periods as are in accordance with the previous habits of the +patient. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1014. Why should there be a well-adjusted thermometer in every +sick-chamber? 1015. What is said of the temperature of the sick-chamber? +1016. Why should the sick-room be kept quiet? 1017. What is said of noise +in the sick-chamber? Of whispering? 1018. Should the habits of the +patient be regarded in reference to the period for eating and sleep? + + -=-=-=-=-=-=-=-=-=-=-=-= + +1019. The deportment and remarks of the nurse to the patient should be +tranquil and encouraging. The illness of a friend, or persons who have +recently died, should not be alluded to in the sick-room. No doubts or +fears of the patient's recovery, either by a look or by a word, should +be communicated by the nurse in the chamber of the sick. When such +information is necessary to be communicated, it is the duty of the +physician to impart it to the sick person. + +1020. The nurse should not confine herself to the sick-room more than +six hours at a time. She should eat her food regularly, sleep at +regular periods, and take exercise daily in the open air. To do this, +let her quietly leave the room when the patient is sleeping. A +watcher, or temporary nurse, may supply her place. There is but little +danger of contracting disease, if the nurse attends to the simple laws +of health, and remains not more than six hours at a time in the +sick-room. + + +DIRECTIONS FOR WATCHERS. + +1021. These necessary assistants, like the nurse, should have +knowledge and practice. They should ever be cheerful, kind, firm, and +attentive in the presence of the patient. + +1022. A simple, nutritious supper should be eaten before entering the +sick-room; and it is well, during the night, to take some plain food. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1019. What should be the deportment of the nurse toward the patient? +Should doubts and fears of the patient's recovery be communicated in +the sick-room? When necessary to impart such intelligence, on whom +does it depend? 1020. How long should a nurse remain in the +sick-chamber at a time? 1021. What qualifications are necessary in a +watcher? 1022. What directions in regard to the food of the watcher? + + -=-=-=-=-=-=-=-=-=-=-=-= + +1023. When watching in cold weather, a person should be warmly +dressed, and furnished with an extra garment, as a cloak or shawl, +because the system becomes exhausted toward morning, and less heat is +generated in the body. + +1024. Light-colored clothing should be worn by those who have care of +the sick, in preference to dark-colored apparel; particularly if the +disease is of a contagious character. Experiments have shown, that +black and other dark colors will absorb more readily the subtile +effluvia that emanate from sick persons, than white or light colors. + +1025. Whatever may be wanted during the night, should be brought into +the sick-chamber, or the adjoining room, before the family retires for +sleep, in order that the slumbers of the patient be not disturbed by +haste, or searching for needed articles. + +1026. The same general directions should be observed by watchers, as +are given to the nurse; nor should the watcher deem it necessary to +make herself acceptable to the patient by exhausting conversation. + +1027. It can hardly be expected that the farmer, who has been laboring +hard in the field, or the mechanic, who has toiled during the day, is +qualified to render all those little attentions that a sick person +requires. Hence, would it not be more benevolent and economical to +employ and _pay_ watchers, who are qualified by knowledge and +_training_, to perform this duty in a faithful manner, while the +kindness and sympathy of friends may be _practically_ manifested by +assisting to defray the expenses of these qualified and useful +assistants? + + -=-=-=-=-=-=-=-=-=-=-=-= + +1023. When watching in cold weather, what precaution is necessary? +1024. What is said relative to the color of the clothing worn in the +sick-room? 1025. What suggestions to watchers relative to the +arrangement of the sick-chamber? 1026. What should watchers observe? +1027. What is said of employing those persons to watch who labor hard +during the day? + + -=-=-=-=-=-=-=-=-=-=-=-= + + + + +APPENDIX. + + +POISONS AND THEIR ANTIDOTES + +1028. POISONING, either from accident or design, is of such frequency +and danger, that it is of the greatest importance that every person +should know the proper mode of procedure in such cases, in order to +render immediate assistance when within his power. + +1029. Poisons are divided into two classes--_mineral_ (which include +the acids) and _vegetable_. + +1030. The first thing, usually, to be done, when it is ascertained +that a poison has been swallowed, is to evacuate the stomach, unless +vomiting takes place spontaneously. Emetics of the sulphate of zinc, +(white vitriol,) or ipecacuanha, (ipecac,) or ground mustard seed, +should be given. + +1031. When vomiting has commenced, it should be aided by large and +frequent draughts of the following drinks: flaxseed tea, gum-water, +slippery-elm tea, barley water, sugar and water, or any thing of a +mucilaginous or diluent character. + + +MINERAL POISONS. + +1032. AMMONIA.--The _water of ammonia_, if taken in an over-dose, and +in an undiluted state, acts as a violent corrosive poison. + +1033. The best and most effectual antidote is _vinegar_. It should be +administered in water, without delay. It neutralizes the ammonia, and +renders it inactive. Emetics should not be given. + + +1034. ANTIMONY.--The _wine of antimony_ and _tartar emetic_, if taken +in over-doses, cause distressing vomiting. In addition to the diluent, +mucilaginous drinks, give a tea-spoonful of the sirup of poppies, +paregoric, or twenty drops of laudanum, every twenty minutes, until +five or six doses have been taken, or the vomiting ceases. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1025. Is it useful to know the antidotes or remedies for poison? 1029. +Into how many classes are poisons divided? 1030. What is the first +thing to be done when it is ascertained that poison has been +swallowed? 1031. What should be taken after the vomiting has +commenced? 1032. What effect has an over-dose of ammonia? 1033. The +antidote? Should an emetic be given for this poison? 1034. What effect +has an over-dose of the wine of antimony or tartar emetic? + + -=-=-=-=-=-=-=-=-=-=-=-= + +1035. The antidotes are _nutgalls_ and _oak bark_, which may be +administered in infusion, or by steeping in water. + + +1036. ARSENIC.--When this has been taken, administer an emetic of +ipecac, speedily, in mucilaginous teas, and use the stomach-pump as +soon as possible. + +1037. The antidote is the _hydrated peroxide of iron_. It should be +kept constantly on hand at the apothecaries' shops. It may be given in +any quantity, without injurious results. + + +1038. COPPER.--The most common cause of poisoning from this metal, is +through the careless use of cooking utensils made of it, on which the +_acetate of copper_ (verdigris) has been allowed to form. When this +has been taken, immediately induce vomiting, give mucilaginous drinks, +or the _white of eggs_, diffused in water. + +1039. The antidote is the _carbonate of soda_, which should be +administered without delay. + + +1040. LEAD.--The _acetate_ (sugar) _of lead_ is the preparation of +this metal, which is liable to be taken accidentally, in poisonous +doses. Induce immediate vomiting, by emetics of ground mustard seed, +sulphate of zinc, and diluent drinks. + +1041. The antidote is diluted _sulphuric acid_. When this acid is not +to be obtained, either the sulphate of magnesia, (epsom salts,) or the +sulphate of soda, (glauber's salts,) will answer every purpose. + + +1042. MERCURY.--The preparation of this mineral by which poisoning is +commonly produced, is _corrosive sublimate_. The mode of treatment to +be pursued when this poison has been swallowed, is as follows: The +_whites of a dozen eggs_ should be beaten in two quarts of cold water, +and a tumbler-full given every two minutes, to induce vomiting. When +the whites of eggs are not to be obtained, soap and water should be +mixed with wheat flour, and given in copious draughts, and the +stomach-pump introduced as soon as possible. Emetics or irritating +substances should not be given. + + +1043. NITRE--_Saltpetre._--This, in over-doses, produces violent +poisonous symptoms. Vomiting should be immediately induced by large +doses of mucilaginous, diluent drinks; but emetics which irritate the +stomach should not be given. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1035. What is the antidote? 1036. What should immediately be done when +arsenic is swallowed? 1037. What is the antidote? Can any quantity of +this preparation of iron be given without injurious results? 1038. +What should be given when verdigris has been taken into the stomach? +1039. What is the antidote? 1040. What should immediately be given +when sugar of lead is taken? 1041. What is the antidote? 1042. Give +the treatment when corrosive sublimate has been swallowed. 1043. What +effect has an over-dose of saltpetre? What treatment should be +adopted? + + -=-=-=-=-=-=-=-=-=-=-=-= + + +1044. ZINC.--Poisoning is sometimes caused by the _sulphate of zinc_, +(white vitriol.) When this takes place, vomiting should be induced, +and aided by large draughts of mucilaginous and diluent drinks. Use +the stomach-pump as soon as possible. + +1045. The antidote is the _carbonate_, or _super-carbonate of soda_. + + +1046. NITRIC, (aqua fortis,) MURIATIC, (MARINE ACID,) OR SULPHURIC +(OIL OF VITRIOL,) ACIDS, may be taken by accident, and produce +poisonous effects. + +1047. The antidote is _calcined magnesia_, which should be freely +administered, to neutralize the acid and induce vomiting. When +magnesia cannot be obtained, the _carbonate of potash_ (salaeratus) may +be given. _Chalk_, powdered and given in solution, or strong _soap +suds_, will answer a good purpose, when the other articles are not at +hand. It is of very great importance that something be given speedily, +to neutralize the acid. One of the substances before mentioned should +be taken freely, in diluent and mucilaginous drinks, as gum-water, +milk, flaxseed, or slippery-elm tea. Emetics ought to be avoided. + + +1048. OXALIC ACID.--This acid resembles the sulphate of magnesia, +(epsom salts,) which renders it liable to be taken, by mistake, in +poisonous doses. Many accidents have occurred from this circumstance. +They can easily be distinguished by tasting a small quantity. _Epsom +salts_, when applied to the tongue, have a very bitter taste, while +_oxalic acid_ is intensely sour. + +1049. The antidote is _magnesia_, between which and the acid a +chemical action takes place, producing the oxalate of magnesia, which +is inert. When magnesia is not at hand, _chalk_, _lime_, or _carbonate +of potash_, (salaeratus,) will answer as a substitute. Give the +antidote in some of the mucilaginous drinks before mentioned. No time +should be lost in introducing the stomach-pump as soon as a surgeon +can be obtained. + + +1050. LEY.--The ley obtained by the leaching of ashes may be taken by +a child accidentally. The antidote is vinegar, or oil of any kind. The +vinegar neutralizes the alkali by uniting with it, forming the acetate +of potash. The oil unites with the alkali, and forms soap, which is +less caustic than the ley. Give, at the same time, large draughts of +mucilaginous drinks, as flaxseed tea, &c. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1044. What is the antidote for white vitriol? 1047. What is the +antidote for aqua fortis and oil of vitriol? Should emetics be +avoided? 1048. How can oxalic acid be distinguished from epsom salts? +1049. What is the antidote for an over-dose of oxalic acid? When +magnesia cannot be obtained, what will answer as a substitute? 1050. +What is the antidote when ley is swallowed? + + -=-=-=-=-=-=-=-=-=-=-=-= + + +VEGETABLE POISONS. + +1051. The vegetable poisons are quite as numerous, and many of them +equally as virulent, as any in the mineral kingdom. We shall describe +the most common, and which, therefore, are most liable to be taken. + + +1052. OPIUM.--This is the article most frequently resorted to by those +wishing to commit suicide, and, being used as a common medicine, is +easily obtained. From this cause, also, mistakes are very liable to be +made, and accidents result from it. Two of its preparations, +_laudanum_ and _paregoric_, are frequently mistaken for each other; +the former being given when the latter is intended. + +1053. _Morphia_, in solution, or _morphine_, as it is more commonly +called by the public, is a preparation of the drug under consideration, +with which many cases of poisoning are produced. It is the active +narcotic principle of the opium; and one grain is equal to six of this +drug in its usual form. + +1054. When an over-dose of opium, or any of its preparations, has been +swallowed, the stomach should be evacuated as speedily as possible. To +effect this, a teaspoonful of ground mustard seed, or as much tartar +emetic as can be held on a five cent piece, or as much _ipecacuanha_ +as can be held on a twenty-five cent piece, should be mixed in a +tumbler of warm water, and one half given at once, and the remainder +in twenty minutes, if the first has not, in the mean time, operated. +In the interval, copious draughts of warm water, or warm sugar and +water, should be drank. + +1055. The use of the stomach-pump, in these cases, is of the greatest +importance, and should be resorted to without delay. After most of the +poison has been evacuated from the stomach, a strong infusion of +_coffee_ ought to be given; or some one of the vegetable acids, such +as _vinegar_, or _lemon-juice_, should be administered. + +1056. The patient should be kept in motion, and salutary effects will +often be produced by dashing a bucket of cold water on the head. +_Artificial respiration_ ought to be established, and kept up for some +time. If the extremities are cold, apply warmth and friction to them. +After the poison has been evacuated from the stomach, stimulants, as +warm wine and water, or warm brandy and water, should be given, to +keep up and sustain vital action. + + +1057. STRAMONIUM--_Thorn-Apple._--This is one of the most active +narcotic poisons, and, when taken in over-doses, has, in numerous +instances, caused death. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1051. Are vegetable poisons as numerous and as virulent in their +effects as mineral? 1052. What is said of opium and its preparations? +1054, 1055, 1056. What treatment should be adopted when an over-dose +of opium or any of its preparations is taken? 1057. What is said of +stramonium? + + -=-=-=-=-=-=-=-=-=-=-=-= + +1058. HYOSCIAMUS--_Henbane._--This article, which is used as a +medicine, if taken in improper doses, acts as a virulent irritating +and narcotic poison. + +1059. The treatment for the two above-mentioned articles is similar to +that of poisoning from over-doses of opium. + + +1060. CONIUM--_Hemlock._--Hemlock, improperly called, by many, +_cicuta_, when taken in an over-dose, acts as a narcotic poison. It +was by this narcotic that the Athenians used to destroy the lives of +individuals condemned to death by their laws. Socrates is said to have +been put to death by this poison. When swallowed in over-doses, the +treatment is similar to that of opium, stramonium, and henbane, when +over-doses are taken. + + +1061. BELLADONNA--_Deadly Nightshade._--CAMPHOR. ACONITE--_Monkshood_, +_Wolfsbane._ BRYONIA--_Bryony._ DIGITALIS--_Foxglove._ +DULCAMARA--_Bittersweet._ GAMBOGE. LOBELIA--_Indian Tobacco._ +SANGUINARIA--_Bloodroot._ OIL OF SAVIN. SPIGELIA--_Pinkroot._ +STRYCHNINE--_Nux vomica._ TOBACCO.--All of these, when taken in +over-doses, are poisons of greater or less activity. The treatment of +poisoning, by the use of any of these articles, is similar to that +pursued in over-doses of opium. (See OPIUM, page 442.) + + +1062. In _all_ cases of poisoning, call a physician as soon as +possible. + + -=-=-=-=-=-=-=-=-=-=-=-= + +1058. Of henbane? 1059. What should be the treatment when an +over-dose of stramonium or henbane is taken? 1060. What name is +sometimes improperly given to _conium_, or hemlock? How was this +narcotic poison used by the Athenians? How are the effects of an +over-dose counteracted? 1061. What is the treatment when an +over-dose of deadly nightshade, monkshood, foxglove, bittersweet, +gamboge, lobelia, bloodroot, tobacco, &c., is taken? 1062. Should a +physician be called in all cases when poison is swallowed? + + -=-=-=-=-=-=-=-=-=-=-=-= + + +A. + +The essential parts of every secretory apparatus are a simple +membrane, apparently textureless, named the _primary_, or _basement +membrane_, certain cells and blood-vessels. The serous and mucous +membrane are examples. + + +B. + +The division and description of the different membranes and tissues +are not well defined and settled by anatomical writers. This is not a +material defect, as a clear description of the different parts of the +system can be given by adopting the arrangement of almost any writer. + + +C. + +FAT is one of the non-nitrogenous substances. It forms the essential +part of the adipose tissue. Chemical analysis shows that all fatty +substances are compounds of carbon, hydrogen, and oxygen. They are +lighter than water, generally fluid at the natural temperature of the +body, and burn with a bright flame, forming water and carbonic acid. + +CASEINE is abundantly found in milk. When dried, it constitutes +cheese. Alcohol, acids, and the stomach of any of the mammalia +coagulate it; and it is also soluble in water. It is found in the +blood, bile, saliva, and the lens of the eye. + +CHONDRINE is a variety of gelatin. It is obtained from cartilage. It +is soluble in warm water, but solidifies on cooling. + +LACTIC ACID is common to all the solids and fluids of the system. It +is found united with potash, soda, lime, or magnesia. + + +D. + +The word _duodenum_ is derived from the Latin, signifying "twelve," +since the intestine, of which this is the name, is usually about +twelve fingers' breadth in length. The _jejunum_ is also from the +Latin _jejunum_, empty, since it is usually found in that condition +after death, as the food seems to pass rapidly through this part of +the intestine. The term _ileum_ is from the Greek, signifying "to +twist," since it always appears in a contorted condition. The name +_caecum_ is derived from the fact of its being a blind or short sack, +perforated by the extremity of the ileum. The name of the next +division of the intestine--_colon_--is from the Greek, "to prohibit," +as the contents of the alimentary canal pass slowly through this +portion. The _rectum_ is named from the straight direction that it +assumes in the latter part of its course. + + +E. + +The food is forced through the alimentary canal by contractions of its +muscular coat, produced by the nervous filaments of the sympathetic +system, not being at all dependent on the cerebro-spinal centre. This +is called the peristaltic, or vermicular motion. The great length of +intestine in all animals, and especially in the herbivorous ones, is +owing to the necessity of exposing the food to a large number of the +lacteals, that the nourishment may all be taken from it. + + +F. + +The different processes through which the food passes before +assimilation are of considerable interest. The mastication and mixture +of the saliva with the food are purely of a mechanical nature. When +any solid or fluid substance is placed upon the tongue, or in contact +with the inner surface of the cheeks, by an involuntary act, the +salivary glands are stimulated to activity, and commence pouring the +saliva into the mouth through the salivary ducts. As soon as +mastication commences, the contraction of the masseter and other +muscles employed in mastication stimulates the salivary glands to +increased action, and a still greater quantity of saliva is secreted +and forced upon the food, which is constantly being ground to a finer +condition, until it is sufficiently reduced for deglutition. + +Whether the salivary fluid acts any other part than simply that of a +demulcent to assist the gastric juice in still further dissolving the +food, is yet a matter of some doubt, although it is found that no +other liquid will equally well subserve the process of digestion and +promote health. + +After the food is in the condition ready to be swallowed, by an +apparently involuntary motion, it is placed upon the back of the +tongue, which carries it backwards to the top of the pharynx, where +the constrictions of the pharynx, aided by the muscles of the tongue +and floor of the mouth, with a sudden and violent movement thrust it +beyond the epiglottis, in order to allow the least necessary time to +the closure of the glottis, after which, by the compression of the +oesophagus, it is forced into the stomach. + +Here it is that the true business of digestion commences. For as soon +as any substance except water enters the stomach, this organ, with +involuntary movements, that seem almost like instinct, commences the +secretion of the gastric juice, and by long-continued contractions of +its muscular coat, succeeds in effecting a most perfect mixture of the +food with this juice, by which the contents of the stomach are reduced +to the softest pulp. + +The gastric juice, in its pure state, is a colorless, transparent +fluid; "inodorous, a little saltish, and perceptibly acid. It +possesses the property of coagulating albumen, and separating the whey +of milk from its curd, and afterwards completely dissolving the curd. +Its taste, when applied to the tongue, is similar to that of +mucilaginous water, slightly acidulated with muriatic acid." The +organs of its secretion are an immense number of tubes or glands, of a +diameter varying from one five hundredth to one three hundredth of an +inch, situated in the mucous coat of the stomach, and receiving their +blood from the gastric arteries. A chemical analysis shows it to +consist of water, mucilage, and the several free acids--muriatic, +acetic, lactic, and butyric, together with a peculiar organic matter +called _pepsin_, which acts after the manner of ferments between the +temperature of 50 deg. and 104 deg. F. + +The true process of digestion is probably owing to the action of +pepsin and the acids, especially if the presence of the chloro-hydric +or muriatic be admitted; since we know, by experiments out of the +body, that chlorine, one of its elements, is a powerful solvent of all +organic substances. + +The antiseptic properties of the gastric juice, as discovered by +experiments made on Alexis St. Martin, doubtless have much influence +on digestion, although their true uses are probably not yet known. + +As soon as the food is reduced to a state of fluidity, the pyloric +orifice of the stomach is unclosed, and it is thrust onwards through +the alimentary canal, receiving in the duodenum the secretions of the +liver and pancreas, after which it yields to the lacteals its nutrient +portion, and the residuum is expelled from the body. + +There have been many hypotheses in regard to the nature of the +digestive process. Some have supposed that digestion is a mere +mechanical process, produced by the motion of the walls of the +stomach; while others, in later times, have considered it as under the +influence of a spirit separate from the individual, who took up his +residence in the stomach and regulated the whole affair; while others +still would make it out to be a chemical operation, and thus +constitute the stomach a sort of laboratory. But to all these +ridiculous hypotheses Sir John Hunter has applied the following +playful language: "Some will have it that the stomach is a mill; +others that it is a fermenting vat; and others that it is a stewpan; +but in my view of the matter, it is neither a mill, a fermenting vat, +nor a stewpan, but a stomach, _a stomach_!" + +At the present day this process is regarded as a complex, and not a +simple operation. It seems to be a process in which the mechanical, +chemical, and vital agencies must all act in harmony and order; for if +one of these be withdrawn, the function cannot be sustained for any +considerable length of time; and of the chemical and mechanical parts +of the process, since the former is much more important, and, as a +matter of course, the vital powers are indispensable, therefore +digestion may be considered as a chemical operation, directly +dependent on the laws of vitality, or of life; since the proper +consistency of the food depends, in a great measure, upon the +character of the solvents, while the secretion of these fluids, their +proper amount, together with the peculiar instinct--as it almost +seems to be--necessary to direct the stomach in its many functions, +are exclusively and entirely dependent on the laws and conditions of +life. + + +G. + +As food is necessary to supply the waste and promote the growth of the +body, it follows that that will be the best adapted to the system +which contains the same chemical elements of which the body is +composed; viz., oxygen, hydrogen, carbon, and nitrogen. These elements +are found in greater or less quantity in all animal food, and in many +vegetable products. Hence, that article of food which contains all +these elements in a proper proportion will tend much more to the +growth and strength of the body than those kinds which are deficient +in one or more of them. Much experience on this point, and scientific +research, seem to show that a reasonable amount of animal food in +health tends to give greater strength of muscle, and a more general +sense of fulness, than in ordinary cases a vegetable diet is able to +do, owing to the presence of nitrogen in animal tissues. Yet there are +examples of the healthiest and strongest men, who live years without a +morsel of animal food; and the fact can only be accounted for, by +supposing that the system has the power to make the most economical +use of the little nitrogen offered to it in the food; or else that it +has by some means the power to abstract it from the atmosphere, and +transform it to the living animal substance. + + +H. + +The proximate principles, which are the most important in nourishing +the body, are albumen and fibrin. These constitute the greater part of +all the softer animal tissues, and are also found in certain classes +of vegetables, such as peas, beans, lentils, and many seeds. Hence, in +many cases, a vegetable diet, especially if embracing any of those +articles, would be sufficient to sustain life, even if no animal food +should be eaten. But no animal can exist for a long time if permitted +only to eat substances destitute of nitrogen, as in the case of a dog +fed entirely on sugar, which lived but thirty days. And owing to this +fact, Baron Liebig proposes to call substances used for food, +containing nitrogen, "elements of nutrition," and those containing an +excess of carbon, "elements of respiration;" since, according to his +view, the food is necessary to support the growth of the body by +replacing the effete and worn-out particles with new matter, and also +to keep up the supply of fuel, in order to promote a sufficient degree +of heat in the system. Accordingly, under the first division would be +included all lean meats and vegetables, such as peas, &c.; while the +fat of animals, vegetable oils, sugars, tubers, (as the potato,) and +all other substances containing starch, would be included under the +latter division. + + +I. + +This definition of exhalants is from the theory of Haller and others. +It is now believed that the fluids exude through the thin coats of the +blood vessels. This process is called _exosmose_, and is the +_exhalation_ of old physiologists. + + +J. + +It is a well-established fact, in animal and vegetable physiology, +that membranes possess the property of allowing fluids and gases to +pass through them in either direction, and also to permit two fluids +to pass in opposite directions at the same time. This property is +designated _endosmose_ when a fluid passes from without a body inward; +and _exosmose_ when the reverse takes place. The first is called +_imbibition_. One of the most striking instances of this, in the human +system, is shown in the lungs, where carbonic acid and water pass out +through the mucous membrane of the bronchial tubes and air-cells; and +the oxygen of the air enters the blood through the same membrane. By +this process of imbibition, the oxygenation of the blood is much more +readily and faithfully accomplished; inasmuch, as by the immense +number of bronchial tubes and air-cells a larger quantity of blood is +exposed to a greater portion of air, than if the blood were directly +laid open to the atmosphere in a mass, or the air were immediately +transmitted through it. + +Since the function of respiration is to free the system of superfluous +carbon and hydrogen, by union with the oxygen of the air, it follows +that the greater the amount of the products to be expelled, the larger +the quantity of oxygen will be required to effect this purpose, as we +find to be the case with those who consume large quantities of food. + +The quantity of oxygen daily consumed through the lungs by an adult is +about 32.5 oz., and the carbon in the food 13.9 oz. But in order to +convert this whole amount of carbon into carbonic acid, which passes +off through the lungs and skin, 37 oz. of oxygen are required; the +remaining 4.5 oz. being absorbed by the skin. If the supply of food +remain the same, while the amount of oxygen in the inspired air is +diminished, the superfluous carbon will induce disease in the system, +as is the case of those persons who are limited in their supply of air +of a proper quality or quantity, and, consequently, have less appetite +for food than those who are abundantly supplied with air of the proper +standard of health; and in children, who proportionally consume more +food than adults, and who are more active, thereby causing a more +rapid circulation of blood, and, consequently, the removal of more +superfluous particles of matter. + +In children we notice the need of air, by their disposition to be much +in the open air, and often inspiring more deeply than is common in +older persons. Also, if the carbon of the food does not have a +requisite supply of oxygen from the air, or other sources, the body +becomes emaciated, although nourishing food may be used. And on the +other hand, if there be a diminished supply of food, but an abundance +of atmospheric air, leanness and emaciation are sure to follow; owing +to the fact that if the oxygen has no waste carbon from the body to +unite with, it combines with the fat, and some other soft portions of +the body, which the Author of nature seems to have provided for this +very purpose; as is seen in the case of hibernating animals, who enter +their places of winter abode sleek and fat, but crawl out in the +spring not merely deprived of their fatty matter, but also with great +diminution of all the softer parts, which have given up their share of +carbon to supply animal heat. One important cause of emaciation in +febrile diseases is the greater rapidity of the pulse and respiration, +which consume more carbon than is afforded by the scanty supply of +food that is taken, although profuse perspiration, which almost always +occurs in some stages of fevers, greatly diminishes the full state of +the body. + + +K. + +The theory of Baron Liebig concerning the change which the blood +experiences in color, in its passage through the lungs, meets with +the approbation of many physiologists, although there are some +important difficulties in the way of fully receiving it. A chemical +analysis of the blood shows it to be composed of albumen and +fibrin, together with some other substances, in small proportions, and +always perceptible traces of iron. He attributes the change in color +to the iron, as this substance enters into combination with carbon +and oxygen. For, as the blood passes through the trunks of the larger +vessels and capillaries, it receives the carbon from the tissues +which are continually transformed, and taking up the oxygen from the +arterialized blood, forms carbonic acid, which unites with the iron, +forming proto-carbonate of iron. This being of a gray color, he +supposes it to be that which, with the other impurities of the blood, +gives the venous blood the dark blue color. Then, as the blood +comes in contact with the oxygen, as it is returned and exposed to +this element in the lungs, the carbonic acid leaves the iron, which +has a stronger affinity for oxygen than for carbonic acid, and forms +the scarlet red peroxide of iron, that gives the characteristic +color to the arterial blood. After this, as the blood is sent out +through the smaller arteries and capillaries, it again gathers carbon +and other impurities from the system, and becomes the dark, venous +blood, thus completing the whole change of color in the circulation. + + +L. + +As already mentioned, different articles of food have been divided +into the azotized and non-azotized, or those which contain nitrogen as +one of their constituents, and those which are nearly destitute of it. +Of these, according to Liebig, the azotized portions are simply to +supply the waste that is continually going on in the body, and promote +its growth in the early stages of existence, or, in other words, the +nutrient portion; while the sugar, starch, &c., are mainly of use in +the respiratory organs. The correctness of this view may be understood +from the fact, that the inhabitants in the colder regions of the earth +consume a much larger quantity of oil and fat than the residents of +hotter climates; and also those dwelling in the temperate zones can +eat with greater impunity a larger quantity of fat meats in the winter +than in the summer, there being then so much more demand for animal +heat than in the summer. + + +M. + +The suggestion of using the bellows in asphyxia, is from the +directions of that distinguished and veteran surgeon, Valentine Mott, +of New York city. The directions in the first part of the paragraph +are the most practical, and best adapted to the wants of the +community. + + + + +GLOSSARY + + +AB-DUC'TOR. [L. _abduco_ to lead away.] A muscle which moves certain +parts, by separating them from the axis of the body. + +AB-DO'MEN. [L. _abdo_, to hide.] That part of the body which lies +between the thorax and the bottom of the pelvis. + +AB-DOM'IN-IS. Pertaining to the abdomen. + +A-CE-TAB'U-LUM. [L. _acetum_, vinegar.] The socket for the head of the +thigh-bone; an ancient vessel for holding vinegar. + +A-CE'TIC. [L. _acetum_, vinegar.] Relating to acetic acid. This is +always composed of oxygen, hydrogen, and carbon, in the same +proportion. + +A-CHIL'LIS. A term applied to the tendon of two large muscles of the +leg. + +A-CRO'MI-ON. [Gr. +akros+, _akros_, highest, and +omos+, _omos_, +shoulder.] A process of the scapula that joins to the clavicle. + +AD-DUC'TOR. [L. _adduco_, to lead to.] A muscle which draws one part +of the body toward another. + +AL-BU-GIN'E-A. [L. _albus_, white.] A term applied to white textures. + +AL-BU'MEN. [L. _albus_, white.] An animal substance of the same nature +as the white of an egg. + +A-LU'MIN-UM. [L.] The name given to the metallic base of alumina. + +AL'VE-O-LAR. [L. _alveolus_, a socket] Pertaining to the sockets of +the teeth. + +AM-MO'NI-A. An alkali. It is composed of three equivalents of hydrogen +and one of nitrogen. + +A-NAS'TO-MOSE. [Gr. +ana+, _ana_, through, and +stoma+, _stoma_, +mouth.] The communication of arteries and veins with each other. + +AN-A-TOM'I-CAL. Relating to the parts of the body, when dissected or +separated. + +A-NAT'O-MY. [Greek +ana+, _ana_, through, and +tome+, _tome_ a +cutting.] The description of the structure of animals. The word +_anatomy_ properly signifies dissection. + +AN'GU-LI. [L. _angulus_, a corner.] A term applied to certain muscles +on account of their form. + +AN-I-MAL'CU-LAE. [L. _animalcula_, a little animal.] Animals that are +only perceptible by means of a microscope. + +AN'NU-LAR. [L. _annulus_, a ring.] Having the form of a ring. + +AN-TI'CUS. [L.] A term applied to certain muscles. + +A-ORT'A. [Gr. +aorte+, _aorte_; from +aer+, _aer_, air, and +tereo+, +_tereo_, to keep.] The great artery that arises from the left +ventricle of the heart. + +AP-O-NEU-RO'SIS. [Gr. +apo+, _apo_, from, and +neuron+, _neuron_, a +nerve.] The membranous expansions of muscles and tendons. The ancients +called every white tendon _neuron_, a nerve. + +AP-PA-RA'TUS. [L. _apparo_, to prepare.] An assemblage of organs +designed to produce certain results. + +AP-PEND'IX. [L., an addition.] Something appended or added. + +A'QUE-OUS. [L. _aqua_, water.] Partaking of the nature of water. + +A-RACH'NOID. [Gr. +arachne+, _arachne_, a spider, and +eidos+, +_eidos_, form.] Resembling a spider's web. A thin membrane that +covers the brain. + +AR'BOR. [L.] A tree. _Arbor vitae._ The tree of life. A term applied to +a part of the cerebellum. + +AR'TE-RY. [Gr. +aer+, _aer_, air, and +tereo+, _tereo_, to keep; +because the ancients thought that the arteries contained only air.] A +tube through which blood flows from the heart. + +A-RYT-E'NOID. [Gr. +arytaina+, _arutaina_, a ewer, and +eidos+, +_eidos_, form.] The name of a cartilage of the larynx. + +AS-CEND'ENS. [L.] Ascending; rising. + +AS-PHYX'I-A. [Gr. +a+, _a_, not, and +sphyxis+, _sphyxis_, pulse.] +Originally, want of pulse; now used for suspended respiration, or +apparent death. + +AS-TRAG'A-LUS. [Gr.] The name of a bone of the foot. One of the tarsal +bones. + +AUD-I'TION. [L. _audio_, to hear.] Hearing. + +AUD-IT-O'RI-US. [L.] Pertaining to the organ of hearing. + +AU'RI-CLE. [L. _auricula_, the external ear; from _auris_, the ear.] A +cavity of the heart. + +AU-RIC'U-LAR. [L. _auricula_.] Pertaining to the auricle. + +AX-IL'LA. [L.] The armpit. + +AX'IL-LA-RY. Belonging or relating to the armpit. + +A-ZOTE'. [Gr. +a+, _a_, not, and +zoe+, _zoe_, life.] Nitrogen. One of +the constituent elements of the atmosphere. So named because it will +not sustain life. + + +BEN-ZO'IC. _Benzoic acid._ A peculiar vegetable acid, obtained from +benzoin and some other balsams. + +BI'CEPS. [L. _bis_, twice, and _caput_, a head.] A name applied to +muscles with two heads at one extremity. + +BI-CUS'PIDS. [L. _bis_ and _cuspis_, a point.] Teeth that have two +points upon their crown. + +BILE. [L. _bilis_.] A yellow, viscid fluid secreted by the liver. + +BI-PEN'NI-FORM. [L. _bis_ and _penna_, a feather.] _Bipenniform +muscle._ Having fibres on each side of a common tendon. + +BRACH'I-AL. [L. _brachium_.] Belonging to the arm. + +BRE'VIS. [L.] _Brevis_, short; _brevior_, shorter. + +BRONCH'I-A, -AE. [L.] A division of the trachea that passes to the +lungs. + +BRONCH'I-AL. Relating to the bronchia. + +BRONCH-I'TIS. [L.] An inflammation of the bronchia. + +BUC-CI-NA'TOR. [L. _buccinum_, a trumpet.] The name of a muscle of the +cheek, so named because used in blowing wind instruments. + +BUR'SAE MU-CO'SA. [L. _bursa_, a purse, and _mucosa_, viscous.] Small +sacs, containing a viscid fluid, situated about the joints, under +tendons. + + +CAE'CUM. [L.] Blind; the name given to the commencement of the colon. + +CALX, CAL'CIS. [L.] The heel-bone. + +CAL'CI-UM. [L.] The metallic basis of lime. + +CAP'IL-LA-RY. [L. _capillus_, a hair.] Resembling a hair; small. + +CAP'SU-LAR. Pertaining to a capsule. + +CAP'SULE. [L. _capsula_, a little chest.] A membranous bag, enclosing +a part. + +CA'PUT. [L.] The head. _Caput coli._ The head of the colon. + +CAR'BON. [L. _carbo_, a coal.] Pure charcoal. An elementary +combustible substance. + +CAR-BON'IC. Pertaining to carbon. + +CAR'DI-AC. [Gr. +kardia+, _kardia_, heart.] Relating to the heart, or +upper orifice of the stomach. + +CAR'NE-A, -AE. [L. _caro_, _carnis_, flesh.] Fleshy. + +CA-ROT'ID. [Gr. +karos+, _karos_, lethargy.] The great arteries of the +neck that convey blood to the heart. The ancients supposed drowsiness +to be seated in these arteries. + +CAR'PAL. [L. _carpus_, the wrist.] Relating to the wrist. + +CAR'PUS, -I. [L.] The wrist. + +CAR'TI-LAGE. [L. _cartilago_.] Gristle. A smooth, elastic substance, +softer than bone. + +CAR-TI-LAG'IN-OUS. Pertaining to cartilage. + +CAU-CA'SIAN. One of the races of men. + +CA'VA. [L.] Hollow. _Vena cava._ A name given to the two great veins +of the body. + +CEL'LU-LAR. [L. _cellula_, a little cell.] Composed of cells. + +CER-E-BEL'LUM. [L.] The hinder and lower part of the brain, or the +little brain. + +CER'E-BRAL. Pertaining to the brain. + +CER'E-BRUM. [L.] The front and large part of the brain. The term is +sometimes applied to the whole contents of the cranium. + +CER'E-BRO-SPI'NAL. Relating to the brain and spine. + +CER'VIX. [L.] The neck. + +CER'VI-CAL. Relating to the neck. + +CHEST. [Sax.] The thorax; the trunk of the body from the neck to the +abdomen. + +CHLO'RINE. [Gr. +chloros+, _chloros_, green.] _Chlorine gas_, so named +from its color. + +CHOR'DA, -AE. [L.] A cord. An assemblage of fibres. + +CHO'ROID. [Gr. +chorion+, _chorion_.] A term applied to several parts +of the body that resemble the skin. + +CHYLE. [Gr. +chulos+, _chulos_, juice.] A nutritive fluid, of a +whitish appearance, which is extracted from food by the action of the +digestive organs. + +CHYL-I-FI-CA'TION. [_chyle_ and L. _facio_, to make.] The process by +which chyle is formed. + +CHYME. [Gr. +chumos+, _chumos_, juice.] A kind of grayish pulp formed +from the food in the stomach. + +CHYM-I-FI-CA'TION. [_chyme_ and L. _facio_, to make.] The process by +which chyme is formed. + +CIL'IA-RY. [L. _cilia_, eyelashes.] Belonging to the eyelids. + +CIN-E-RI'TIOUS. [L. _cinis_, ashes.] Having the color of ashes. + +CLAV'I-CLE. [L. _clavicula_, from _clavis_, a key.] The collar-bone; +so called from its resemblance in shape to an ancient key. + +CLEI'DO. A term applied to some muscles that are attached to the +clavicle. + +CO-AG'U-LUM. [L.] A coagulated mass, a clot of blood. + +COC'CYX. [Gr.] An assemblage of bones joined to the sacrum. + +COCH'LE-A. [Gr. +kochlo+, _kochlo_, to twist; or L. _cochlea_, a +screw.] A cavity of the ear resembling in form a snail shell. + +CO'LON. [Gr.] A portion of the large intestine. + +CO-LUM'NA, -AE.[L.] A column or pillar. + +COM-MU'NIS. [L.] A name applied to certain muscles. + +COM-PLEX'US. [L. _complector_, to embrace.] The name of a muscle that +embraces many attachments. + +COM-PRESS'OR. [L. _con_, together, and _premo_, _pressus_, to press.] +A term applied to some muscles, that compress the parts to which they +are attached. + +CON'DYLE. [Gr. +kondulos+, _kondulos_, a knuckle, a protuberance.] A +prominence on the end of a bone. + +CON-JUNC-TI'VA. [L. _con_, together, and _jungo_, to join.] The +membrane that covers the anterior part of the globe of the eye. + +COP'PER. A metal of a pale, red color, tinged with yellow. + +COR-A'COID. [Gr. +korax+, _korax_, a crow, and +eidos+, _eidos_, +form.] A process of the scapula shaped like the beak of a crow. + +CO'RI-ON. [Gr. +chorion+, _chorion_, skin.] The true skin. + +CORN'E-A. [L. _cornu_, a horn.] The transparent membrane in the fore +part of the eye. + +COS'TA. [L. _costa_, a coast, side, or rib.] A rib. + +CRIB'RI-FORM. [L. _cribrum_, a sieve, and _forma_, form.] A plate of +the ethmoid bone, through which the olfactory nerve passes to the +nose. + +CRI'COID. [Gr. +krikos+, _krikos_, a ring, and +eidos+, _eidos_, +form.] A name given to a cartilage of the larynx, from its form. + +CRYS'TAL-LINE. [L. _crystallinus_, consisting of crystal.] _Crystalline +lens._ One of the humors of the eye. It is convex, white, firm, and +transparent. + +CU'BI-TUS, -I. [L. _cubitus_, the elbow.] One of the bones of the +forearm, also called the _ulna_. + +CU'BOID. [Gr. +kubos+, _kubos_, a cube, and +eidos+, _eidos_, form.] +Having nearly the form of a cube. + +CU-NE'I-FORM. [L. _cuneus_, a wedge.] The name of bones in the wrist +and foot. + +CUS'PID. [L. _cuspis_, a point.] Having one point. + +CU-TA'NE-OUS. [L. _cutis_, skin.] Belonging to the skin. + +CU'TI-CLE. [L. _cutis_.] The external layer of the skin. + +CU'TIS VE'RA. [L. _cutis_, and _vera_, true.] The internal layer of +the skin; the true skin. + + +DEL'TOID. [Gr. +delta+, _delta_, the Greek letter +Delta+, and ++eidos+, _eidos_, form.] The name of a muscle, that resembles in form +the Greek letter +Delta+. + +DENS. [L.] A tooth. + +DENT'AL. [L. _dens_, tooth.] Pertaining to the teeth. + +DE-PRESS'OR. [L.] The name of a muscle that draws down the part to +which it is attached. + +DERM'OID. [Gr. +derma+, _derma_, the skin, and +eidos+, _eidos_, +form.] Resembling skin. + +DE-SCEND'ENS. [L. _de_ and _scando_, to climb.] Descending, falling. + +DI'A-PHRAGM. [Gr. +diaphragma+, _diaphragma_, a partition.] The +midriff; a muscle separating the chest from the abdomen. + +DI-AR-RHOE'A. [Gr. +diarreo+, _diarrheo_, to flow through.] A morbidly +frequent evacuation of the intestines. + +DI-AS'TO-LE. [Gr. +diastello+, _diastello_, to put asunder.] The +dilatation of the heart and arteries when the blood enters them. + +DI-GES'TION. [L. _digestio_.] The process of dissolving food in the +stomach, and preparing it for circulation and nourishment. + +DIG-I-TO'RUM. [L. _digitus_, a finger.] A term applied to certain +muscles of the extremities. + +DOR'SAL. [L. _dorsum_, the back.] Pertaining to the back. + +DU-O-DE'NUM. [L. _duodenus_, of twelve fingers' breadth.] The first +portion of the small intestine. + +DU'RA MA'TER. [L. _durus_, hard, and _mater_, mother.] The outermost +membrane of the brain. + +DYS'EN-TER-Y. [Gr. +dys+, _dus_, bad, and +enteria+, _enteria_, +intestines.] A discharge of blood and mucus from the intestines +attended with tenesmus. + +DYS-PEP'SI-A. [Gr. +dys+, _dus_, bad, and +pepto+, _pepto_, to +digest.] Indigestion, or difficulty of digestion. + + +EN-AM'EL. [Fr.] The smooth, hard substance which covers the crown or +visible part of a tooth. + +EP-I-DERM'IS. [Gr. +epi+, _epi_, upon, and +derma+, _derma_, the +skin.] The scarf-skin; the cuticle. + +EP-I-GLOT'TIS. [Gr. +epi+, _epi_, upon, and +glotta+, _glotta_, the +tongue.] One of the cartilages of the glottis. + +EU-STA'CHI-AN TUBE. A channel from the fauces to the middle ear, named +from Eustachius, who first described it. + +EX'CRE-MENT. [L. _excerno_, to separate.] Matter excreted and ejected; +alvine discharges. + +EX-CRE-MEN-TI'TIAL. Pertaining to excrement. + +EX'CRE-TO-RY. A little duct or vessel, destined to receive secreted +fluids, and to excrete or discharge them; also, a secretory vessel. + +EX-HA'LANT. [L. _exhalo_, to send forth vapor.] Having the quality of +exhaling or evaporating. + +EX-TENS'OR. [L.] A name applied to a muscle that serves to extend any +part of the body; opposed to _Flexor_. + + +FA'CIAL. [L. _facies_, face.] Pertaining to the face. + +FALX. [L. _falx_, a scythe.] A process of the dura mater shaped like a +scythe. + +FAS'CI-A. [L. _fascia_, a band.] A tendinous expansion or aponeurosis. + +FAS-CIC'U-LUS, -LI. [L. _fascis_, a bundle.] A little bundle. + +FAUX, -CES. [L.] The top of the throat. + +FEM'O-RAL. Pertaining to the femur. + +FEM'O-RIS. A term applied to muscles that are attached to the femur. + +FE'MUR. [L.] The thigh-bone. + +FE-NES'TRA, -UM. [L. _fenestra_, a window.] A term applied to some +openings into the internal ear. + +FI'BRE. [L. _fibra_.] An organic filament, or thread, which enters +into the composition of every animal and vegetable texture. + +FI'BRIN. A peculiar organic substance found in animals and vegetables; +it is a solid substance, tough, elastic, and composed of thready +fibres. + +FI'BROUS. Composed or consisting of fibres. + +FI'BRO-CAR'TI-LAGE. An organic tissue, partaking of the nature of +fibrous tissue and that of cartilage. + +FIB'U-LA. [L., a clasp.] The outer and lesser bone of the leg. + +FIB'U-LAR. Belonging to the fibula. + +FIL'A-MENT. [L. _filamenta_, threads.] A fine thread, of which flesh, +nerves, skin, &c., are composed. + +FLEC'TION. [L. _flectio_.] The act of bending. + +FOL'LI-CLE. [L. _folliculus_, a small bag.] A gland; a little bag in +animal bodies. + +FORE'ARM. The part of the upper extremity between the elbow and hand. + +FOS'SA. [L., a ditch.] A cavity in a bone, with a large aperture. + +FRAE'NUM. [L., a bridle.] _Fraenum linguae._ The bridle of the tongue. + +FUNC'TION. [L. _fungor_, to perform.] The action of an organ or system +of organs. + +FUN'GI-FORM. [L. _fungus_ and _forma_.] Having terminations like the +head of a fungus, or a mushroom. + + +GAN'GLI-ON, -A. [Gr.] An enlargement in the course of a nerve. + +GAS'TRIC. [Gr. +gaster+, _gaster_, the stomach.] Belonging to the +stomach. + +GAS-TROC-NE'MI-US. [Gr. +gaster+, _gaster_, the stomach, and +kneme+, +_kneme_, the leg.] The name of large muscles of the leg. + +GEL'A-TIN. [L. _gelo_, to congeal.] A concrete animal substance, +transparent and soluble in water. + +GLE'NOID. [Gr. +glene+, _glene_, a cavity.] A term applied to some +articulate cavities of bones. + +GLOS'SA. [Gr.] The tongue. Names compounded with this word are applied +to muscles of the tongue. + +GLOS'SO-PHA-RYN'GI-AL. Relating to the tongue and pharynx. + +GLOT'TIS. [Gr.] The narrow opening at the upper part of the larynx. + +GLU'TE-US. [Gr.] A name given to muscles of the hip. + + +HEM'OR-RHAGE. [Gr. +haima+, _haima_, blood and +regnuo+, _regnuo_, to +burst.] A discharge of blood from an artery or vein. + +HU'MER-US. [L.] The bone of the arm. + +HY'A-LOID. [Gr.] A transparent membrane of the eye. + +HY'DRO-GEN. [Gr. +hydor+, water, and +gennao+, to generate.] A gas +which constitutes one of the elements of water. + +HY'GI-ENE. [Gr. +hugieinon+, _hugieinon_, health.] The part of +medicine which treats of the preservation of health. + +HY'OID. [Gr. +u+ and +eidos+, _eidos_, shape.] A bone of the tongue +resembling the Greek letter upsilon in shape. + +HY-OID'E-US. Pertaining to the hyoid bone. + +HY'PO-GLOS'SAL. Under the tongue. The name of a nerve of the tongue. + + +IL'E-UM. [Gr. +eilo+, _eilo_, to wind.] A portion of the small +intestines. + +IL'I-AC. [From the above.] The flank; pertaining to the small +intestine. + +IL'I-UM. The haunch-bone. + +IN-CI'SOR. [L. _incido_, to cut.] A front tooth that cuts or divides. + +IN'DEX. [L. _indico_, to show.] The fore-finger; the pointing finger. + +IN-NOM-I-NA'TA. [L. _in_, not, and _nomen_, name.] Parts which have no +proper name. + +IN-OS'CU-LATE. [L. _in_ and _osculatus_, from _osculor_, to kiss.] To +unite, as two vessels at their extremities. + +IN'TER. [L.] Between. + +IN-TER-COST'AL. [L. _inter_, between, and _costa_, a rib.] Between the +ribs. + +IN-TER-NO'DI-I. [L. _inter_, between, and _nodus_, knot.] A term +applied to some muscles of the forearm. + +IN-TER-STI'TIAL. [L. _inter_, between, and _sto_, to stand.] +Pertaining to or containing interstices. + +IN-TES'TINES. [L. _intus_, within.] The canal that extends from the +stomach to the anus. + +I'RIS. [L., the rainbow.] The colored circle that surrounds the pupil +of the eye. + +I'VO-RY. A hard, solid, fine-grained substance of a fine white color; +the tusk of an elephant. + + +JE-JU'NUM. [L., empty.] A portion of the small intestine. + +JU'GU-LAR. [L. _jugulum_, the neck.] Relating to the throat. The great +veins of the neck. + + +LA'BI-UM, LA'BI-I. [L.] The lips. + +LAB'Y-RINTH. [Gr.] The internal ear, so named from its many windings. + +LACH'RY-MAL. [L. _lachryma_, a tear.] Pertaining to tears. + +LAC'TE-AL. [L., _lac_, milk.] A small vessel or tube of animal bodies +for conveying chyle from the intestine to the thoracic duct. + +LAM'I-NA, -AE. [L.] A plate, or thin coat lying over another. + +LAR'YNX. [Gr. +larunx+, _larunx_.] The upper part of the windpipe. + +LAR-YN-GI'TIS. Inflammation of the larynx. + +LA-TIS'SI-MUS, -MI. [L., superlative of _latus_, broad.] A term +applied to some muscles. + +LE-VA'TOR. [L. _levo_, to raise.] A name applied to a muscle that +raises some part. + +LIG'A-MENT. [L. _ligo_, to bind.] A strong, compact substance serving +to bind one bone to another. + +LIN'E-A, -AE. [L.] A line. + +LIN'GUA, -AE. [L.] A tongue. + +LIV'ER. The name of one of the abdominal organs, the largest gland in +the system. It is situated below the diaphragm, and secretes the +bile. + +LOBE. A round projecting part of an organ. + +LON'GUS, LON'GI-OR. [L., long, longer.] A term applied to several +muscles. + +LUM'BAR. [L. _lumbus_, the loins.] Pertaining to the loins. + +LYMPH. [L. _lympha_, water.] A colorless fluid in animal bodies, and +contained in vessels called lymphatics. + +LYM-PHAT'IC. A vessel of animal bodies that contains or conveys +lymph. + + +MAG-NE'SI-UM. The metallic base of magnesia. + +MAG'NUS, -NA, -NUM. [L., great.] A term applied to certain muscles. + +MA'JOR. [L., greater.] Greater in extent or quantity. + +MAN'GA-NESE. A metal of a whitish gray color. + +MAR'ROW. [Sax.] A soft, oleaginous substance, contained in the +cavities of bones. + +MAS-SE'TER. [Gr. +massaomai+, _massaomai_, to chew.] The name of a +muscle of the face. + +MAS'TI-CATE, MAS-TI-CA'TION. [L. _mastico_.] To chew; the act of +chewing. + +MAS'TOID. [Gr. +mastos+, _mastos_, breast, and +eidos+, _eidos_, +form.] the name of a process of the temporal bone behind the ear. + +MAS-TOID'E-US. A name applied to muscles that are attached to the +mastoid process. + +MAX-IL'LA. [L.] The jaw-bone. + +MAX'IL-LA-RY. Pertaining to the jaw. + +MAX'I-MUS, -UM. [L., superlative of _magnus_, great.] A term applied +to several muscles. + +ME-A'TUS. [L. _meo_, to go.] A passage or channel. + +ME-DI-AS-TI'NUM. A membrane that separates the chest into two parts. + +ME'DI-UM, -A. [L.] The space or substance through which a body passes +to any point. + +MED'UL-LA-RY. [L., _medulla_, marrow.] Pertaining to marrow. + +ME-DUL'LA OB-LON-GA'TA. Commencement of the spinal cord. + +ME-DUL'LA SPI-NA'LIS. The spinal cord. + +MEM'BRA-NA. A membrane; a thin, white, flexible skin formed by fibres +interwoven like net-work. + +MEM'BRA-NOUS. Relating to membrane. + +MES'EN-TER-Y. [Gr. +mesos+, _mesos_, the middle, and +enteron+, +_enteron_, the intestine.] The membrane in the middle of the +intestines, by which they are attached to the spine. + +MES-EN-TER'IC. Pertaining to the mesentery. + +MET-A-CAR'PAL. Relating to the metacarpus. + +MET-A-CAR'PUS. [Gr. +meta+, _meta_, after, and +karpos+, _karpos_, +wrist.] The part of the hand between the wrist and fingers. + +MET-A-TAR'SAL. Relating to the metatarsus. + +MET-A-TAR'SUS. [Gr. +meta+, _meta_, after, and +tarsos+, _tarsos_, the +tarsus.] The instep. A term applied to seven bones of the foot. + +MID'RIFF. [Sax. _mid_, and _hrife_, the belly.] See DIAPHRAGM. + +MIN'I-MUS, -I. [L.] The smallest. A term applied to several muscles. + +MI'NOR. [L.] Less, smaller. A term applied to several muscles. + +MI'TRAL. [L. _mitra_, a mitre.] The name of the valves in the left +side of the heart. + +MO-DI'O-LUS. [L. _modus_, a measure.] A cone in the cochlea around +which the membranes wind. + +MO'LAR. [L. _mola_, a mill.] The name of some of the large teeth. + +MOL'LIS. [L.] Soft. + +MO'TOR, -ES. [L. _moveo_, to move.] A mover. A term applied to certain +nerves. + +MU'COUS. Pertaining to mucus. + +MU'CUS. A viscid fluid secreted by the mucous membrane, which it +serves to moisten and defend. + +MUS'CLE. A bundle of fibres enclosed in a sheath. + +MUS'CU-LAR. Relating to a muscle. + +MY-O'DES. A term applied to certain muscles of the neck. + + +NA'SAL. Relating to the nose. + +NA'SUS. [L., the nose.] The nostrils. + +NERVE. An organ of sensation and motion in animals. + +NERV'OUS. Relating to the nerves. + +NEU-RI-LEM'A. [Gr. +neuron+, _neuron_, a nerve, and +lemma+, _lema_, a +sheath.] The sheath or covering of a nerve. + +NI'GRUM. [L.] Black. + +NI'TRO-GEN. That element of the air which is called azote. + +NU-TRI'TION. The art or process of promoting the growth, or repairing +the waste of the system. + + +OC-CIP-I-TA'LIS. Pertaining to the back part of the head. + +OC'CI-PUT. [L. _ob_ and _caput_, the head.] The hinder part of the +head. + +OC-U-LO'RUM. Of the eyes. + +OC'ULUS, -I. [L.] The eye. + +OE-SOPH'A-GUS. [Gr. +oio+, _oio_, to carry, and +phago+, _phago_, to +eat.] The name of the passage through which the food passes from the +mouth to the stomach. + +O-LEC'RA-NON. [Gr. +olene+, _olene_, the cubit, and +kranon+, +_kranon_, the head.] The elbow; the head of the ulna. + +OL-FACT'O-RY. [L. _oleo_, to smell, and _facio_, to make.] Pertaining +to smelling. + +O-MEN'TUM. [L.] The caul. + +O'MO. [Gr. +omos+, _omos_, the shoulder.] Names compounded of this +word are applied to muscles attached to the shoulder. + +OPH-THAL'MIC. [Gr. +ophthalmos+, _ophthalmos_, the eye.] Belonging to +the eye. + +OP-PO'NENS. That which acts in opposition to something. The name of +two muscles of the hand. + +OP'TI-CUS, OP'TIC. [Gr. +optomai+, _optomai_, to see.] Relating to the +eye. + +OR-BIC'U-LAR. [L. _orbis_, a circle.] Circular. + +OR-BIC-U-LA'RIS. A name applied to several muscles. + +OR'GAN. A part of the system destined to exercise some particular +function. + +OR'I-GIN. Commencement; source. + +OS. [L.] A bone; the mouth of any thing. + +O'RIS. [L. _os_, _oris_.] Of the mouth. + +OS HY-OID'ES. [Gr. See HYOID.] The name of the bone at the base of the +tongue. + +OS'MA-ZOME. [Gr. +osme+, _osme_, smell, and +zomos+, _zomos_, broth.] +A principle obtained from animal fibre which gives the peculiar taste +to broth. + +OS'SA. [L., plural of _os_, bone.] Bones. + +OS'SE-OUS. Pertaining to bones. + +OS-SI-FI-CA'TION. The formation of bones in animals. + +OS'SI-FY. [L. _ossa_, bones, and _facio_, to make.] To convert into +bone. + +OS'SIS. Of a bone. + +O-VA'LE. [L.] The shape of an egg. + +OX-AL'IC. Pertaining to sorrel. _Oxalic acid_ is the acid of sorrel. +It is composed of two equivalents of carbon and three of oxygen. + +OX'Y-GEN. A permanently elastic fluid invisible and inodorous. One of +the components of atmospheric air. + + +PA-LA'TUM. [L.] The palate; the roof of the mouth. + +PAL-PE-BRA'RUM. [L. _palpebra_, the eyelid.] Of the eyelids. + +PAL'MAR. [L. _palma_, the palm.] Belonging to the hand. + +PAL-MA'RIS. A term applied to some muscles attached to the palm of the +hand. + +PAN'CRE-AS. [Gr. +pan+, _pan_, all, and +kreas+, _kreas_, flesh.] The +name of one of the digestive organs. + +PAN-CRE-AT'IC. Belonging to the pancreas. + +PA-PIL'LA, -AE. [L.] Small conical prominences. + +PA-RAL'Y-SIS. Abolition of function whether of intellect, sensation, +or motion. + +PA-REN'CHY-MA. [Gr. +parencheo+, _parengcheo_, to pour through.] The +substance contained between the blood vessels of an organ. + +PA-ROT'ID. [Gr. +para+, _para_, near, and +otos+, _otos_, the gen. of ++ous+, _ous_, the ear.] The name of the largest salivary gland. + +PA-TEL'LA, -AE. [L.] The knee-pan. + +PA-THET'I-CUS, -CI. [Gr. +pathos+, _pathos_, passion.] The name of the +fourth pair of nerves. + +PEC'TUS. [L.] The chest. + +PEC'TO-RAL. Pertaining to the chest. + +PEC-TO-RA'LIS. Belonging to the chest. + +PE'DIS. [L., gen. of _pes_, the foot.] Of the foot. + +PEL'I-TONGS. A term applied to masses of fat. + +PEL'LI-CLE. [L., dim. of _pellis_, the skin.] A thin skin or film. + +PEL'VIC. Relating to the pelvis. + +PEL'VIS. [L.] The basin formed by the large bones at the lower part of +the abdomen. + +PEN'NI-FORM. [L. _penna_, a feather.] Having the form of a feather, or +quill. + +PER-I-CAR'DI-UM. [Gr. +peri+, _peri_, around, and +kardia+, _kardia_, +the heart.] A membrane that encloses the heart. + +PER-I-CHON'DRI-UM. [Gr. +peri+, _peri_, around, and +chondros+, +_chondros_, cartilage.] A membrane that invests cartilage. + +PER-I-CRA'NI-UM. [Gr. +peri+, and +kranion+, _kranion_, the cranium.] +A membrane that invests the skull. + +PER'MA-NENT. Durable; lasting. + +PER-I-STAL'TIC. [Gr. +peristello+, _peristello_, to involve.] A +movement like the crawling of a worm. + +PER-SPI-RA'TION. [L. _per_, through, and _spiro_, to breathe.] The +excretion from the skin. + +PHAL'ANX, -GES. [Gr. +phalanx+, _phalanx_, an army.] Three rows of +small bones forming the fingers or toes. + +PHA-LAN'GI-AL. Belonging to the fingers or toes. + +PHA-RYN'GE-AL. Relating to the pharynx. + +PHAR'YNX. [Gr. +pharunx+, _pharunx_.] The upper part of the +oesophagus. + +PHOS'PHOR-US. [Gr. +phos+, _phos_, the light, and +phero+, _phero_, to +bear.] A combustible substance, of a yellowish color, semi-transparent, +resembling wax. + +PHREN'IC. [Gr. +phren+, _phren_, the mind.] Belonging to the +diaphragm. + +PHYS-I-OL'O-GY. [Gr. +phusis+, _phusis_, nature, and +logos+, _logos_, +a discourse.] The science of the functions of the organs of animals +and plants. + +PI'A MA'TER. [L., good mother.] The name of one of the membranes of +the brain. + +PIG-MEN'TUM. [L.] Paint; a preparation of colors. + +PIN'NA. [L., a wing.] A part of the external ear. + +PLA-TYS'MA. [Gr. +platus+, _platus_, broad.] A muscle of the neck. + +PLEU'RA, -AE. [Gr. +pleura+, _pleura_, the side.] A thin membrane that +covers the inside of the thorax, and also forms the exterior coat of +the lungs. + +PLEU'RAL. Relating to the pleura. + +PLEX'US. [L. _plecto_, to weave together.] Any union of nerves, +vessels, or fibres, in the form of net-work. + +PNEU-MO-GAS'TRIC. [Gr. +pneumon+, _pneumon_, the lungs, and +gaster+, +_gaster_, the stomach.] Belonging to both the stomach and lungs. + +POL'LI-CIS. [L.] A term applied to muscles attached to the fingers and +toes. + +PONS. [L.] A bridge. _Pons varolii._ A part of the brain formed by the +union of the crura cerebri and cerebelli. + +POP-LIT-E'AL. [L. _poples_, the ham.] Pertaining to the ham or +knee-joint. A name given to various parts. + +POS'TI-CUS. [L.] Behind; posterior. A term applied to certain +muscles. + +POR'TI-O DU'RA. [L., hard portion.] The facial nerve; 8th pair. + +POR'TI-O MOL'LIS. [L., soft portion.] The auditory nerve; 7th pair. + +PO-TAS'SI-UM. [L.] The metallic basis of pure potash. + +PRO-BOS'CIS. [Gr. +pro+, _pro_, before, and +bosko+, _bosko_, to +feed.] The snout or trunk of an elephant or other animal. + +PROC'ESS. A prominence or projection. + +PRO-NA'TOR. [L. _pronus_, turned downward.] The muscle of the forearm +that moves the palm of the hand downward. + +PSO'AS. [Gr. +psoai+, _psoai_, the loins.] The name of two muscles of +the leg. + +PUL-MON'IC. } + } +PUL'MO-NA-RY. } [L. _pulmo_, the lungs.] Belonging or + } relating to the lungs. +PUL-MO-NA'LIS. } + +PU'PIL. A little aperture in the centre of the iris, through which the +rays of light pass to the retina. + +PY-LOR'IC. Pertaining to the pylorus. + +PY-LOR'US. [Gr. +puloros+, _puloros_, a gate keeper.] The lower +orifice of the stomach, with which the duodenum connects. + + +RA'DI-US. [L., a ray, a spoke of a wheel.] The name of one of the +bones of the forearm. + +RA-DI-A'LIS. Radial; belonging to the radius. + +RA'DI-ATE. Having lines or fibres that diverge from a point. + +RA'MUS. [L.] A branch. A term applied to the projections of bones. + +REC-RE-MEN-TI'TIAL. [L. _re_, again, and _cerno_, to secrete.] +Consisting of superfluous matter separated from that which is +valuable. + +REC'TUM. The third and last portion of the intestines. + +REC'TUS, -I. [L.] Straight; erect. A term applied to several muscles. + +RE-SID'U-AL. Pertaining to waste matter. + +RE-SID'U-UM. [L.] Waste matter. The faeces. + +RES-PI-RA'TION. [L. _re_, again, and _spiro_, to breathe.] The act of +breathing. Inspiring air into the lungs and expelling it again. + +RE-SPI'RA-TO-RY. Pertaining to respiration; serving for respiration. + +RET'I-NA. [L., _rete_, a net.] The essential organ of sight. One of +the coats of the eye, formed by the expansion of the optic nerve. + +RO-TUN'DUM, -A. [L.] Round; circular. + +RU'GA, -AE. [L.] A wrinkle; a fold. + + +SAC'CU-LUS. [L., dim. of _saccus_, a bag.] A little sac. + +SA'CRAL. Pertaining to the sacrum. + +SA'CRUM. [L., sacred.] The bone which forms the posterior part of the +pelvis, and is a continuation of the spinal column. + +SA-LI'VA. [L.] The fluid which is secreted by the salivary glands, +which moistens the food and mouth. + +SAL'I-VA-RY. That which belongs to the saliva. + +SAN'GUIN-E-OUS. [L. _sanguis_, the blood.] Bloody; abounding with +blood; plethoric. + +SAR-TO'RI-US. [L. _sartor_, a tailor.] A term applied to a muscle of +the thigh. + +SCA'LA, -AE. [L., a ladder.] Cavities of the cochlea. + +SCA-LE'NUS. [Gr. +skalenos+, _skalenos_, unequal.] A term applied to +some muscles of the neck. + +SCAPH'OID. [Gr. +skaphe+, _skaphe_, a little boat.] The name applied +to one of the wrist-bones. + +SCAP'U-LA. [L.] The shoulder-blade. + +SCAP'U-LAR. Relating to the scapula. + +SCARF-SKIN. The outer, thin integument of the body; the cuticle. + +SCI-AT'IC. [Gr., pertaining to the loins.] The name of the large nerve +of the loins and leg. + +SCLE-ROT'IC. [Gr. +skleros+, _skleros_, hard.] A membrane of the eye. + +SE-BA'CEOUS. [L., _sebum_, tallow.] Pertaining to fat; unctuous +matter. + +SE-CRE'TION. The act of secerning; the act of producing from the blood +substances different front the blood itself, as bile, saliva. The +matter secreted, as mucus, bile, &c. + +SE-CRE'TO-RY. Performing the office of secretion. + +SE-CUN'DUS. Second. A term applied to certain muscles. + +SEM-I-CIR'CU-LAR. Having the form of a half circle. The name of a part +of the ear. + +SEM-I-TEN-DI-NO'SUS. [L. _semi_, half and _tendo_, a tendon.] The name +of a muscle. + +SEP'TUM. [L.] A membrane that divides two cavities from each other. + +SE'ROUS. Thin; watery. Pertaining to serum. + +SE'RUM. [L.] The thin, transparent part of blood. + +SER-RA'TUS. [L. _serro_, to saw.] A term applied to some muscles of +the trunk. + +SIG'MOID. [Gr.] Resembling the Greek +s+, sigma. + +SI-LI'CI-UM. A term applied to one of the earths. + +SI'NUS. [L., a bay.] A cavity, the interior of which is more expanded +than the entrance. + +SKEL'E-TON. [Gr. +skello+, _skello_, to dry.] The aggregate of the +hard parts of the body; the bones. + +SO'DI-UM. The metallic base of soda + +SPHINC'TER. [Gr. +sphingo+, _sphingo_, to restrict.] A muscle that +contracts or shuts an orifice. + +SPI'NAL CORD. A prolongation of the brain. + +SPI-NA'LIS. Relating to the spine. + +SPINE. A thorn. The vertebral column; back-bone. + +SPI'NOUS. Belonging to the spinal column. + +SPLEEN. The milt. It is situated in the abdomen, and attached to the +stomach. + +SPLEN'IC. Relating to the spleen. + +SPLE'NI-US. The name of a muscle of the neck. + +STA'PES. The name of one of the small bones of the ear. + +STER'NUM. The breast-bone. The bone that forms the front of the chest +from the neck to the stomach. + +STOM'ACH. The principal organ of the digestive apparatus. + +STRA'TUM. [L. _sterno_, to stew.] A bed; a layer. + +STY'LOID. [L. _stylus_, a pencil.] An epithet applied to processes +that resemble a style, a pen. + +SUB-CLA'VI-AN. [L. _sub_, under, and _clavis_, a key.] Situated under +the clavicle. + +SUB-LI'MIS. High in place. + +SUB-LIN'GUAL. [L. _sub_, under, and _lingua_, the tongue.] Situated +under the tongue. + +SUB-MAX'IL-LA-RY. [L. _sub_, under, and _maxilla_, the jaw-bone.] +Located under the jaw. + +SUL'PHUR. A simple, mineral substance, of a yellow color, brittle, +insoluble in water, but fusible by heat. + +SU-PE-RI-O'RIS. A term applied to certain muscles. + +SU-PI-NA'TOR. [L.] A muscle that turns the palm of the hand upward. + +SUT'URE. [L. _suo_, to sew.] The seam or joint that unites the bones +of the skull. + +SYN-O'VI-A. [Gr. +syn+, _sun_, with, and +oon+, _oon_, an egg.] The +fluid secreted into the cavities of joints for the purpose of +lubricating them. + +SYN-O'VI-AL. Pertaining to synovia. + +SYS'TEM. An assemblage of organs composed of the same tissues, and +intended for the same functions. + +SYS-TEM'IC. Belonging to the general system. + +SYS'TO-LE. [Gr. +systello+, _sustello_, to contract.] The contraction +of the heart and arteries for expelling the blood and carrying on the +circulation. + + +TAR'SAL. Relating to the tarsus. + +TAR'SUS. [L.] The posterior part of the foot. + +TEN'DON. [Gr. +teino+, _teino_, to stretch.] A hard, insensible cord, +or bundle of fibres, by which a muscle is attached to a bone. + +TEN'DI-NA, -AE. Pertaining to a tendon. + +TENS'OR. A muscle that extends a part. + +TEN-TAC'U-LA, -AE. [L. _tento_, to seize.] A filiform process or organ +on the bodies of various animals. + +TEN-TO'RI-UM. [L. _tendo_, to stretch.] A process of the dura mater +which lies between the cerebrum and cerebellum. + +TE'RES. [L. _teres_, round.] An epithet given to many organs, the +fibres of which are collected in small bundles. + +THO'RAX. [Gr.] That part of the skeleton that composes the bones of +the chest. The cavity of the chest. + +THO-RAC'IC. Relating to the chest. + +THY'ROID. [Gr. +thureos+, _thureos_, a shield.] Resembling a shield. A +cartilage of the larynx. + +TIB'I-A. [L., a flute.] The large bone of the leg. + +TIB-I-A'LIS, TIB'I-AL. Relating to the tibia. + +TIS'SUE. The texture or organization of parts. + +TON'SIL. [L.] A glandular body in the throat or fauces. + +TRA'CHE-A. [Gr. +trachus+, _trachus_, rough.] The windpipe. + +TRA'CHE-AL. Belonging to the trachea. + +TRANS-VERSE', TRANS-VER-SA'LIS. Lying in a cross direction. + +TRA-PE'ZI-US. The name of a muscle, so called from its form. + +TRI'CEPS. [L. _tres_, three, and _caput_, head.] Three. A name given +to muscles that have three attachments at one extremity. + +TRI-CUS'PID. [L. _tres_, three, and _cuspis_, point.] The triangular +valves in the right side of the heart. + +TROCH'LE-A. [Gr. +trochalia+, _trochalia_, a pulley.] A pulley-like +cartilage, over which the tendon of a muscle of the eye passes. + +TROCH-LE-A'RIS. The name of a muscle of the eye. + +TRUNK. The principal part of the body, to which the limbs are +articulated. + +TU'BER-CLE. [L. _tuber_, a bunch.] A small push, swelling, or tumor, +on animal bodies. + +TU-BER-OS'I-TY. The state of being knobbed or protuberant. + +TYM'PAN-UM. [L.] The middle ear. + + +UL'NA. [L.] A bone of the forearm. + +UL'NAR, UL-NA'RIS. Relating to the ulna. + +U'RIC. [Gr. +ouron+, _ouron_, urine.] An acid contained in urine, and +in gouty concretions. + +U-VE'A. [L. _uva_, a grape.] Resembling grapes. A thin membrane of the +eye. + +U'VU-LA. A soft body, suspended from the palate, near the aperture of +the nostrils, over the glottis. + + +VAC'CINE VI'RUS. [L. _vacca_, a cow, _virus_, poison.] Pertaining to +cows; derived from cows. + +VALVE. Any membrane, or doubling of any membrane, which prevents +fluids from flowing back in the vessels and canals of the animal +body. + +VAL'VU-LA, -AE. A valve. + +VAS'CU-LAR. [L. _vasculum_, a vessel.] Pertaining to vessels; +abounding in vessels. + +VAS'TUS. [L.] Great, vast. Applied to some large muscles. + +VEINS. Vessels that convey blood to the heart. + +VE'NOUS. Pertaining to veins. + +VEN'TRI-CLE. [L. _venter_, the stomach.] A small cavity of the animal +body. + +VEN-TRIC'U-LAR. Relating to ventricles. + +VER-MIC'U-LAR. [L. _vermiculus_, a little worm.] Resembling the +motions of a worm. + +VERM-I-FORM'IS. [L. _vermis_, a worm, and _forma_, form.] Having the +form and shape of a worm. + +VERT'E-BRA, -AE. [L. _verto_, to turn.] A joint of the spinal column. + +VERT'E-BRAL. Pertaining to the joints of the spinal column. + +VES'I-CLE. [L. _vesica_, a bladder.] A little bladder, or a portion of +the cuticle separated from the cutis vera and filled with serum. + +VES'TI-BULE. [L.] A porch of a house. A cavity belonging to the ear. + +VIL'LI. [L.] Fine, small fibres. + +VI'RUS. [L. poison.] Foul matter of an ulcer; poison. + +VI'TAL. [L. _vita_, life.] Pertaining to life. + +VIT'RE-OUS. [L. _vitrum_, glass.] Belonging to glass. A humor of the +eye. + +VO'LAR. [L. _vola_, the hollow of the hand or foot.] Belonging to the +palm of the hand. + +VO'MER. [L. a ploughshare.] One of the bones of the nose. + + +ZYG-O-MAT'I-CUS. [Gr. +zugos+, _zugos_, a yoke.] A term applied to +some muscles of the face, from their attachment. + + + + +INDEX. + + +A. PAGE. + + ABDOMEN, 34 + ABSORPTION, 181 + ----, Varieties of, 183 + ----, Cutaneous, 185 + ACETABULUM, 38 + ACIDS, Acetic, 28 + ----, Benzoic, 28 + ----, Muriatic, 440 + ----, Nitric, 440 + ----, Oxalic, 28, 440 + ----, Sulphuric, 440 + AIR, Composition of the, 223 + ----, Influence of, on the Muscles, 90 + ----, Quality of the, 223, 318 + ----, Quantity inhaled, 222 + ----, Quantity exhaled, 228 + ----, Impure Air, the Effects of, 232 + AIR VESICLES, 212 + ALBUMEN, 27 + ANIMAL HEAT, 252 + AORTA, 159 + ----, Valves of the, 157 + APPARATUS, 18 + ARTERIES, Structure of the, 158 + ----, Cutaneous, 285 + ----, Pulmonary, 158 + ATTITUDE, Effects of, on Digestion, 152 + ----, Effects of, on the Voice, 274 + ----, Effects of, in Respiration, 245 + AURICLES of the Heart, 156 + ASPHYXIA, from Drowning, 249 + ----, from Electricity, 250 + ----, from Hanging, 250 + ----, from Carbonic Gas, 251 + AZOTE, 26 + + +B. + + BATHING, Necessity of, 311 + ----, Methods of, 313 + ----, Proper Time for, 316 + ----, Influence of, on the System, 316 + ----, Frequency of, 317 + BEDS, 309 + BILE, 122 + BLOOD, Composition of, 154 + ----, Color of, 204 + ----, Quantity of, 171 + ----, Change of, 225 + ----, Impure, Effects of, 205 + BONES, Anatomy of the, 29 + ----, Physiology of the, 48 + ----, Hygiene of the, 53 + ----, of the Head, 32 + ----, of the Trunk, 34 + ----, of the Upper Extremities, 39 + ----, of the Lower Extremities, 42 + ----, Composition of, 29 + ----, Ossification of, 30 + ----, Union of fractured, 62 + ----, Influence of Position on the, 55 + BRAIN, 329 + ----, Functions of the, 346 + ----, Effects of Impure Blood on the, 360 + ----, Effects of inadequate Mental Exertion, 361 + ----, Effects of excessive Mental Exertion, 363 + ----, Directions for exercising the, 368 + ----, Membranes of the, 334 + ----, Injuries of the, 377 + BRONCHIA, 212 + BRONCHITIS, 214 + BURNS AND SCALDS, 319 + BURSAE MUCOSAE, 46 + + +C. + + CAECUM, 118 + CAPILLARIES, 163 + CARBON, 26 + CARBONIC GAS, where formed, 224 + ----, Effects of, when inhaled, 230 + ----, Effects of, on Combustion, 230 + ----, Effects of, on Respiration, 231 + CARPUS, 41 + CARTILAGE, 45 + ---- of the Larynx, 269 + CAUL, 123 + CELLULAR TISSUE, 19 + CEREBELLUM, 331 + + CEREBRUM, 330 + CHEST, 35 + ----, Compression of the, 56 + ----, Influence of the Size of the, 239 + CHILBLAINS, 321 + CHLORINE, 27 + CHYLE, 126 + CHYME, 126 + CIRCULATORY ORGANS, Anatomy, 154 + ----, Physiology of the, 164 + ----, Hygiene of the, 172 + CLAVICLE, 39 + CLOTHING, Kind of, 301 + ----, Amount of, 305 + ----, Cleanliness of, 308 + COCCYX, 38 + COLDS, Treatment of, 248 + COLON, 119 + CONSUMPTION, how frequently produced, 247 + CORNS, Treatment of, 295 + CUTICLE, Structure of the, 282 + ----, Use of the, 293 + CUTIS VERA, Structure of the, 283 + + +D. + + DEFINITIONS, General, 13 + DIAPHRAGM, 73, 215 + DIGESTIVE ORGANS, Anatomy of the, 113 + ----, Physiology of the, 124 + ----, Hygiene of the, 129 + ----, Influence of the Mind on the, 148 + ----, Influence of Pure Air on the, 151 + ----, Influence of Position on the, 152 + DRINKS, how taken, 145 + DROWNED PERSONS, Treatment of, 249 + DUODENUM, 117 + + +E. + + EAR, Bones of, 34, 415 + EPIGLOTTIS, 125, 270 + EXHALANTS, 192 + EXERCISE, how it should be taken, 91 + ----, Influence of, on the Bones, 53 + ----, Influence of, on Muscles, 85 + ----, Influence of, on the Circulation, 173 + EYE, 394 + EXPIRATION, how effected, 220 + + +F. + + FACE, Bones of the, 34 + FASCIA, 66 + FAT, 67, 195 + FEMUR, 42 + FIBRE, 18 + FIBRIN, 27 + FIBULA, 42 + FILAMENT, 18 + FLANNEL, Use of, 302 + FLUIDS, Use of, 17 + FOLLICLE, 192 + FOOD, Quantity of the, 129 + ----, Quality of the, 134 + ----, Manner in which it is taken, 142 + ----, Condition of the system, when taken, 146 + FOOT, Bones of the, 44 + FROZEN LIMBS, Treatment of, 320 + + +G. + + GASTRIC JUICE, 125 + GELATIN, 27 + GLANDS, 193 + ----, Gastric, 116 + ----, Lachrymal, 402 + ----, Lymphatic, 183 + ----, Mesenteric, 121 + ----, Oil, 288 + ----, Perspiratory, 290 + ----, Salivary, 114 + GLOTTIS, 271 + + +H. + + HAIR, 322 + HEART, 154 + ----, Auricles of the, 156 + ----, Ventricles of the, 156 + HEAT, Animal, 252 + ----, Hygiene of, 261 + HEARING, Anatomy of the Organs of, 414 + ----, Physiology of the Organs of, 420 + ----, Hygiene of the Organs of, 422 + HUMERUS, 39 + HEMORRHAGE, Means of arresting, 175 + HYDROGEN, 26 + + +I. + + ILEUM, 118 + INTESTINES, 117 + INNOMINATUM, 37 + + INSPIRATION, how effected, 219 + IRON, 25 + + +J. + + JEJUNUM, 118 + JOINTS, Structure of the, 45 + + +L. + + LACTEALS, 120, 181 + LAMINAE, 17 + LARYNX, 268 + LARYNGITIS, 276 + LIGAMENTS, 23, 47 + ----, Use of, 50 + ----, Capsular, 40 + LIGHT, Influence on the Skin, 318 + LIME, 25 + LIVER, 122 + LUNGS, 209 + LYMPH, 30 + LYMPHATICS, Anatomy of the, 181 + ----, Physiology of the, 183 + ----, Hygiene of the, 188 + ----, Cutaneous, 287 + + +M. + + MAGNESIA, 25 + MARROW, Uses of, 24 + + MEDIASTINUM, 211 + MEDULLA OBLONGATA, 333 + MEMBRANE, 19 + ----, Adipose, 20 + ----, Cellular, 19 + ----, Dermoid, 22, 282 + ----, Mucous, 21 + ----, Muscular, 24 + ----, Serous, 21 + MESENTERY, 120 + METACARPUS, 41 + MOUTH, Structure of, 113 + MUCUS, 28 + MUSCLES, Anatomy of, 64 + ----, Physiology of, 76 + ----, Hygiene of, 85 + ----, Compression of, 93, 276 + ----, Exhaustion of, 87, 101 + ----, Effects of Pure Blood on, 89 + ----, Effects of Pure Air on the, 90 + ----, Effects of Light on the, 90 + ----, Influence of the Mind on, 93 + ----, Influence of Position on, 90 + ----, Intercostal, 216 + ----, Respiratory, 216 + + +N. + + NAILS, 324 + NERVES, Cranial, 335, 350 + ----, Cutaneous, 286 + ----, Respiratory, 340, 352 + ----, Spinal, 341, 351 + ----, Sympathetic, 343, 356 + NERVOUS SYSTEM, Anatomy of, 327 + ----, Physiology of, 346 + ----, Hygiene of, 358 + NITROGEN, 26 + NOSE, Structure, 389 + NURSES, Directions for, 433 + NUTRITION, 200 + ----, Hygiene of, 205 + + +O. + + OESOPHAGUS, 116 + OIL-GLANDS, Structure of the, 288 + ----, Use of the, 297 + OMENTUM, 123 + ORGAN, 18 + ORGANIC AND INORGANIC BODIES, Difference between, 14 + ORIFICE, Cardiac, 116 + ----, Pyloric, 116 + OSMAZOME, 28 + OXYGEN, 26 + ----, Quantity at each Inspiration, 222 + + +P. + + PAPILLA, 284 + PANCREAS, 122 + PAROTID GLAND, 114 + PATELLA, 42 + PERICARDIUM, 155 + PERICHONDRIUM, 31 + PERICRANIUM, 31 + PERIOSTEUM, 31 + PELVIS, Bones of the, 37 + PERSPIRATORY APPARATUS, 290 + ---- Use of, 298 + PHALANGES, 42, 45 + PHARYNX, 115 + PHOSPHORUS, 26 + PLEURA, 211 + POISONS, and their Antidotes, 439 + + POTASH, 25 + PRESERVATION OF HEALTH, 425 + + +R. + + RADIUS, 41 + READING, Proper Position in, 275 + RECTUM, 120 + REMOVAL OF DISEASE, 426 + RESPIRATORY ORGANS, Anatomy of, 209 + ----, Physiology of, 217 + ----, Hygiene of, 228 + RETINA, 397 + RIBS, 35 + ROOMS, Ventilation of, 233 + ----, Warming of, 238 + + +S. + + SACRUM, 38 + SALIVA, Its Use, 124 + SCAPULA, 39 + SECRETORY ORGANS, Anatomy of, 192 + ----, Physiology of, 193 + ----, Hygiene of, 197 + SENSES, 378 + SICK-ROOM, Ventilation of, 236 + SITTING, Proper Position in, 99 + SKELETON, 29 + SKIN, Anatomy of the, 282 + ----, Physiology of the, 293 + ----, Hygiene of the, 301 + SKULL, Structure of, 32 + SLEEP, Necessity of, 92 + SLEEPING-ROOMS, Ventilation of, 235 + SMELL, Anatomy of the Organs of, 389 + ----, Physiology of the Organs of, 391 + SODA, 25 + SOLIDS, Arrangement of, 17 + SOUND, 273 + SPINAL COLUMN, Structure of, 36 + ----, Curvature of, 57, 60 + SPINAL CORD, 36, 340 + SPLEEN, 123 + SPRAINS, 63 + STAMMERING, how improved, 281 + STERNUM, 35 + STOMACH, 116 + SUBLINGUAL GLAND, 115 + SUBMAXILLARY GLAND, 115 + SULPHUR, 26 + SUTURES, 33 + SYNOVIAL MEMBRANE, 46 + SYNOVIA, 49 + SYSTEM, 18 + + +T. + + TARSUS, 42 + TASTE, Anatomy of the Organs of, 384 + ----, Physiology of the Organs of, 386 + TEETH, Anatomy of the, 105 + ----, Physiology of the, 109 + ----, Hygiene of the, 110 + TENDONS, 23, 65 + THORACIC DUCT, 120 + THORAX, 35 + THROAT, Extraneous Bodies in, 281 + TIBIA, 42 + TISSUE, 18 + ----, Adipose, 20 + ----, Cartilaginous, 23 + ----, Fibrous, 22 + ----, Osseous, 23 + ----, Nervous, 24 + TOUCH, Sense of, 378 + ----, Hygiene of the, 379 + TRACHEA, 212 + + +U. + + ULNA, 40 + UVEA, 396 + + +V. + + VALVES of the Heart, 157 + ----, Use of the, 164 + ----, of the Veins, 162 + VEINS, 160 + ----, Cutaneous, 285 + VENTILATION, 233 + VENTRICLES of the Heart, 156 + VERTEBRA, 36 + VISION, Anatomy of the Organs of, 394 + ----, Physiology of the Organs of, 404 + ----, Hygiene of the Organs of, 410 + VOCAL ORGANS, Anatomy of the, 268 + ----, Physiology of the, 272 + ----, Hygiene of the, 274 + VOCAL CORDS, 270 + + +W. + + WATCHERS, Directions for, 136 + WOUNDS, Treatment of, 178 + WRITING, Proper Position when, 103 + + + + +KEY TO ANATOMICAL OUTLINE PLATES. + + +SUGGESTIONS TO TEACHERS. + +In using these plates, we would suggest, that the pupil carefully +examine the illustrating cuts interspersed with the text, in +connection with the lesson to be recited. The similarity between these +and the plates will enable the pupil to recite, and the teacher to +conduct his recitation, from the latter. + +Let a pupil show the situation of an organ, or part, on an anatomical +outline plate, and also give its structure; while other members of the +class note all omissions and misstatements. Another pupil may give the +use of that organ, and if necessary, others may give an extended +explanation. The third may explain the laws on which the health of the +part depends, while other members of the class supply what has been +omitted. After thus presenting the subject in the form Of topics, +questions may be proposed promiscuously, from each paragraph, and +where examples occur in the text, let other analogous ones be given. + +If the physiology and hygiene of a given subject have not been +studied, confine the recitation to those parts only on which the pupil +is prepared. When practicable, the three departments should be united; +but this can only be done when the chapter on the hygiene has been +learned, while the physiology can be united with the anatomy, in all +chapters upon physiology. + + +PLATE I. + +A FRONT VIEW OF THE SKELETON. + +_Bones of the Head._ 7, The sphenoid bone. 8, The frontal bone. 10, +The parietal bone. 11, The os unguis. 12, The superior maxillary bone, +(upper jaw.) 13, The nasal bone. 14, The ethmoid bone. 15, The malar +bone, (cheek-bone.) 16, The vomer. 17, The inferior maxillary bone, +(the lower jaw.) _a_, Its body. _b_, Its ramus, or branch. 18, The +teeth. + +_Bones of the Trunk._ 1, 1, The spinal column. 2, The sternum. 3, 3, +The ribs. 4, The sacrum. 5, The innominatum. + +_Bones of the Upper Extremities._ 19, The clavicle, (collar-bone.) 20, +The scapula, (shoulder blade.) 21, The humerus. 22, The ulna. 23, The +radius. 24, 25, 26, 27, 28, 29, 30, 31, The bones of the carpus +(wrist.) 32, 32, 32, The five bones of the metacarpus, (the palm of +the hand.) 33, 33, 33, The first range of finger-bones. 34, 34, The +second range of finger-bones. 35, 35, 35, The third range of +finger-bones. + +_Bones of the Lower Extremities._ 36, The femur, (thigh-bone.) 37, The +patella, (knee-pan.) 38, The tibia, (shin-bone.) 39, The fibula. 40, +40, 40, The bones of the tarsus, (instep.) 41, 41, The bones of the +metatarsus, (middle of the foot.) 42, 42, The bones of the toes. + + +ARTICULATIONS. (Left side of the plate.) + +_Ligaments of the Trunk._ 1, 1, The common spinal ligament. 2, 2, The +intervertebral ligament, (cartilage between the vertebrae.) 9, 10, 11, +12, Articulations of the ribs with the spinal column. 13, 13, 14, 15, +16, Ligaments that connect the cartilages of the ribs with the +sternum. + +_Ligaments of the Upper Extremities._ 25, The ligament that connects +the clavicle and sternum. 27, The ligament that connects the upper rib +and clavicle. 28, 29, 30, Ligaments that connect the clavicle and +scapula. 31, 32, 33, 34, Ligaments of the shoulder-joint. 35, 35, 36, +Ligaments of the elbow-joint. 37, 38, 39, 40, Ligaments of the wrist. +41, 42, 43, 44, Ligaments of the fingers. + +_Ligaments of the Lower Extremities._ 49, 49, Ligaments of the +hip-joint. 50, 50, Ligaments of the patella. 51, 52, 53, 54, 55, +Ligaments of the knee-joint. 56, A large bursa mucosa. 57, The +ligament of the tibia and fibula. 58, 58, The interosseous ligament. +59, 59, Ligaments of the ankle-joint 60, 61, 62, Ligaments of the +metatarsus. 63, 64, Ligaments of the toes. + +A, The brachial artery. B, The brachial vein. C, The radial artery D, +The femoral artery. E, The femoral vein. F, G, The anterior tibia +artery. + + +PLATE II. + +A BACK VIEW OF THE SKELETON. + +_Bones of the Head._ 5, The occipital bone. 6, The parietal bone. 7, +The temporal bone. 8, The frontal bone. 9, The sphenoid bone. 15, The +malar bone. 16, The nasal bone. 17, The superior maxillary bone, +(upper jaw.) 18, The inferior maxillary bone, (lower jaw.) 19, The +teeth. + +_Bones of the Trunk._ 1, 1, The spinal column. 2, The sacrum. 3, The +coccyx. 20, The innominatum. 4, 4, The ribs. + +_Bones of the Upper Extremities._ 21, The clavicle, (collar-bone.) 22, +The scapula, (shoulder-blade.) 23, The humerus. 24. The ulna, 25, The +radius. 26, 27, 28, 29, 30, 31, 32, The bones of the carpus, (wrist.) +33, 33, 33, The bones of the metacarpus, (palm of the hand.) 34, 34, +34, The first range of finger-bones. 35, 35, The second range of +finger-bones. 36, 36, 36, The third range of finger-bones. + +_Bones of the Lower Extremities._ 37, The femur, (thigh-bone.) 38, The +patella, (knee-pan.) 39, The tibia, (shin-bone.) 40, The fibula. 41, +42, 43, 44, 45, The bones of the tarsus, (instep.) 46, 46, The bones +of the metatarsus, (middle of the foot.) 47, 47, Bones of the toes. + + +ARTICULATIONS. (Left side of the plate.) + +_Ligaments of the Trunk._ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, Ligaments of +the spinal column. 14, 14, 15, 15, Ligaments that connect the ribs and +spinal column. 11, 11, 21, 22, 23, 24, 25, 26, Ligaments that connect +the sacrum and innominatum. + +_Ligaments of the Upper Extremities._ 27, 28, Ligaments that +connect the clavicle and scapula. 29, The capsular ligament of the +shoulder-joint. 30, 30, Ligaments of the elbow. 31, 32, 33, 34, +Ligaments of the carpus, (wrist.) + +_Ligaments of the Lower Extremities._ 9, Tendon of the gluteus muscle. +35, The capsular ligament of the hip-joint. 36, 36, Ligaments of the +knee-joint. 37, The ligament that connects the tibia and fibula. 38, +The interosseous ligament. 39, 40, Ligaments of the ankle-joint. + + +PLATE III. + +A FRONT VIEW OF THE MUSCLES. + +_Muscles of the Head and Neck._ 7, The sterno-mastoideus muscle. 8, +The sterno-hyoideus muscle. 9, The omo-hyoideus muscle. 10, The +trapezius muscle. 11, The orbicularis oculi muscle. 12, The frontal +muscle. 14, The orbicularis oris muscle. 15, The elevator muscle of +the nostrils. 16, The zygomatic muscle. 17, The depressor of the lower +lip. 18, The depressor anguli oris muscle. 19, The triangular muscle +of the nose. 20, 21, The aural muscles. 22, The masseter muscle. + +_Muscles of the Trunk._ 2, 3, The external oblique muscles. + +_Muscles of the Upper Extremities._ 1, The grand pectoral muscle. 3, +4, The serratus muscle. 23, The deltoid muscle. 24, The biceps +brachialis muscle. 25, The coraco-brachialis muscle. 26, The anterior +brachial muscle. 27, The triceps brachialis muscle. 28, The long +supinator muscle. 29, The external radial muscle. 30, The pronator +teres muscle. 31, The anterior radial muscle. 32, The palmaris brevis +muscle. 33, The anterior ulnar muscle. 35, The palmar muscle. 36, The +abductor muscle of the thumb. 37, The adductor muscle of the thumb. +38, 39, Small flexor muscles of the thumb. 40, The abductor muscle of +the little finger. 41, 41, The lumbricales muscles. 61, 61, The +bifurcation of the tendons of the superficial flexor muscle, in the +fingers. + +_Muscles of the Lower Extremities._ 42, The fascia lata muscle. 43, +The sartorius muscle. 44, The rectus femoris muscle. 45, The vastus +externus muscle. 46, The vastus internus muscle. 47, The internal +straight muscle. 48. The pectineus muscle. 49, The adductor muscle. +50, The psoas muscle. 51, The tibialis anticus muscle. 52, The long +extensor muscle of the great toe. 53, The long extensor muscle of the +toes. 54, The anterior peroneal muscle. 55, The long lateral peroneal +muscle. 56, 57, The gastrocnemii muscles. 58, The long flexor muscle +of the great toe. 69, The short extensor muscles of the toes. 60, The +abductor muscle of the great toe. + +The figures and letters on the left side of the plate, indicate the +position of important fasciae, that cover the muscles and enclose the +tendons. + + +PLATE IV. + +BACK VIEW OF THE MUSCLES. + +_Muscles of the Head and Neck._ 4, The sterno-mastoideus muscle. 5, +The complexus muscle. 6, The mylo-hyoideus muscle. 7, 8, The +occipito-frontalis muscle. 9, The masseter muscle. 10, 11, 12, The +anterior, middle, and posterior aural muscles. 13, The temporal +muscle. + +_Muscles of the Trunk._ 1, 1, The trapezius muscle. 2, The latissimus +dorsi muscle. 3, The rhomboideus muscle. 4, The external oblique +muscle. + +_Muscles of the Upper Extremities._ 5, The deltoid muscle. 6, 7, The +infra-spinatus muscle. 9, The triceps extensor muscle. 10, The +internal brachial muscle. 11, The long supinator muscle. 12, The +external radial muscle. 13, The second external radial muscle. 14, The +anconeus muscle. 15, 16, The extensor digitorum communis muscle. 17, +The extensor carpi ulnaris muscle. 18, The flexor carpi ulnaris. 19, +20, The extensor ossis metacarpi pollicis muscles. 21, An extensor +muscle of the thumb. 22, 28, Interossii muscles. + +_Muscles of the Lower Extremities._ 29, The gluteus maximus muscle. +30, The gluteus medius muscle. 31, The biceps flexor cruris muscle. +32, The semi-tendinosus muscle. 33, The semi-membranosis muscle. 34, +The gracilis muscle. 35, The adductor muscle. 36, The vastus externus +muscle. 37, The sartorius muscle. 38, 39, The gastrocnemii muscles. +40, The long peroneal muscle. 41, The external peroneal muscle. 42, +The long flexor muscle of the great toe. 43, The long extensor muscle +of the toes. 44, The short extensor muscle of the toes. 47, The short +flexor muscle of the toes. + +The figures and letters on the left side of the plate, indicate the +position of membranous fasciae which envelop the muscles and tendons. + + +PLATE V. + +ORGANS OF THE THORAX AND ABDOMEN. + +Fig. 1. _The Mouth and Neck._ (A Side view.) 1, The upper lip. 2, The +lower lip. 3, The upper jaw. 4, The lower jaw. 5, The tongue. 6, The +hard palate, (roof of the mouth.) 7, The parotid gland. 8, The +sublingual gland. T, The larynx. 10, The pharynx. 11, The oesophagus. +12, The upper portion of the spinal column. C, The spinal cord. + +_The Chest and its Organs._ 9, 9, The trachea. R, The right auricle of +the heart. L, The left auricle. 13, The left ventricle of the heart. +14, The right ventricle. 15, The aorta. 16, The pulmonary artery. 17, +The vena cava descendens. 18, The right subclavian vein. 19, The left +subclavian vein. 20, The right jugular vein. 21, The left jugular +vein. 22, The right carotid artery. 23, The left carotid artery. 24, +25, 26, The upper, middle, and lower lobes of the right lung. 27, 28, +The upper and lower lobes of the left lung. 29, 29, 29, The diaphragm. +P, P, P, P, The pleura, that lines the cavity of the chest. S, S, The +clavicles. O, O, O, O, The ribs. M, M, M, M, Muscles of the chest. 40, +The thoracic duct, opening into the left subclavian vein. + +_The Abdomen and its Organs._ 30, The stomach. 31, 32, The right and +left lobe of the liver. F, The fissure that separates the two lobes. +33, The gall bladder. 34, 34, The duodenum. 35, The ascending colon. +36, The transverse colon. 37, The descending colon. 38, 38, 38, 38, +The small intestine. 39, 39, The walls of the abdominal cavity turned +down. 41, The spleen. + +Fig. 2. _The Relation of the Lacteals and Thoracic Duct._ 1, 1, A +section of the small intestine. 2, 2, 2, 2, 2, 2, 2, 2, Mesenteric +glands, through which the lacteals from the intestine pass. 3, Several +lacteal vessels entering the enlarged portion and commencement of the +thoracic duct. 5, 5, 5, The thoracic duct. 6, The thoracic duct +opening into the left subclavian vein. 7, (See 40, Fig. 1.) 8, The +right subclavian vein. 9, The vena cava descendens. 10, 11, 11, The +aorta. 12, The carotid arteries. 13, 13, The jugular veins. 14, The +vena azagos. 15, 15, The spinal column. 16, The diaphragm. + +Fig. 3. _The Relation of the Larynx, Trachea, Bronchia, and +Air-cells._ 1, 1, 1, An outline of the right lung. 2, 2, 2, An outline +of the left lung. 3, The larynx. 4, The trachea. 5, The right +bronchia. 6, The left bronchia. 7, 7, 7, 7, Divisions of the right +bronchia. 8, 8, 8, 8, Divisions of the left bronchia. 9, 9, 9, 9, 9, +9, Air-cells. + +Fig. 4. _An ideal View of a lateral and vertical Section of the +Larynx._ 1, 1, The superior vocal cords, (ligaments.) 2, 2, The +inferior vocal cords. 3, 3, The glottis. 4, 4, The ventricles of the +larynx. + + +PLATE VI. + +HEART, ARTERIES, AND VEINS + +Fig. 1. _The Heart and large Arteries._ 1, The right auricle of the +heart. 2, The right ventricle of the heart. 3, The left auricle. 4, +The left ventricle. 5, The pulmonary artery. 6, The aorta. 7, 7, The +descending aorta. 8, The arteria innominata. 9, The left carotid +artery. 10, The left subclavian artery. 56, The right subclavian +artery. + +_Arteries of the Neck and Head._ 15, The right carotid artery. 16, The +left carotid artery. 17, The right temporal artery. 50, The right +facial artery. 54, The left temporal artery. + +_Arteries of the Upper Extremities._ 11, 11, The left brachial artery. +12, The left radial artery. 13, 13, The right brachial artery. 14, The +right radial artery. 51, The right ulnar artery. + +_Arteries of the Lower Extremities._ 18, The left iliac artery. 19, +The right iliac artery. 20, The left femoral artery. 21, The right +femoral artery. 22, The peroneal artery. 23, The left anterior tibial +artery. 24, The muscular artery. 25, 25, The right and left arteria +profunda. 26, The right anterior tibial artery. 27, The right peroneal +artery. + +_The Veins of the Neck and Head._ 28, The vena cava descendens. 29, +The left subclavian vein. 30, The right subclavian vein. 31, The right +jugular vein. 32, The left jugular vein. 53, The right temporal vein. +55, The left temporal vein. 49, The right facial vein. + +_Veins of the Upper Extremities._ 33, The left brachial vein. 34, The +left radial vein. 35, The right brachial vein. 36, The right radial +vein. 51, The right ulnar vein. + +_Veins of the Lower Extremities._ 37, The vena cava ascendens. 38, The +left iliac vein. 39. The right iliac vein. 40, The left femoral vein. +41, The right femoral vein. 42, The left anterior tibial vein. 43, The +left peroneal vein. 44, The right anterior tibial vein. 45, The right +peroneal vein. 46, 46, The profunda veins. 47, The muscular veins. 48, +48, 48, 48, 48, 48, Intercostal arteries and veins. + +Fig. 2. _The Relation of the Cavities of the Heart to the large +Blood-vessels._ 1, The vena cava descendens. 2, The vena cava +ascendens. 3, The right auricle of the heart. 4, The opening between +the right auricle and right ventricle. 5, The right ventricle. 6, The +tricuspid valves. 7, The pulmonary artery. 8, 8, The branches of the +pulmonary artery that pass to the right and left lung. 9, The +semilunar valves of the pulmonary artery. 10, The left pulmonary +veins. 11, The right pulmonary veins. 12, The left auricle. 13, The +opening between the left auricle and left ventricle. 14, The left +ventricle. 15, The mitral valves. 16, 16, The aorta. 17, The semilunar +valves of the aorta. 18, The septum between the right and left +ventricle. + +Fig. 3. _An ideal View of the Heart, Arteries, and Veins._ A, The +right auricle. B, The right ventricle. C, The tricuspid valves. D, The +opening between the right auricle and right ventricle. E, The left +auricle. F, the left ventricle. G, The mitral valves. H, The opening +between the left auricle and left ventricle. I, The septum between the +right and left ventricle. K, The pulmonary artery. L, The semilunar +valves of the pulmonary artery. M, M, The right pulmonary artery. N, +N, The left pulmonary artery. O, O, O, O, O, O, The capillary vessels +of the lungs. P, P, P, The right pulmonary vein. Q, Q, The left +pulmonary vein. R, R, The aorta. S, The semilunar valves of the aorta. +T, T, A branch of the aorta to the upper extremities. U, U, U, U, A +branch to the lower extremities. V, V, V, V, V, V, The capillary +vessels at the extremity of the branches of the aorta. W, W, The +descending vena cava. X, X, X, The ascending vena cava. + +In Figs. 1, 2, 3, the course of the blood through the circulatory +vessels is indicated by arrows. + + +PLATE VII. + +THE PULMONARY CIRCULATION. + +Fig. 1. 1, The right auricle of the heart. 2, The left auricle. 3, The +right ventricle of the heart. 4, The left ventricle. 5, The pulmonary +artery. 6, The branch of the pulmonary artery to the left lung. 7, The +branch of the pulmonary artery to the right lung. 8, 8, 8, 8, 8, 8, 8, +8, 8, 8, Branches of the pulmonary artery in the right and left lung. +9, 9, 9, 9, 9, 9, Air-cells. 10, 10, 10, 10, 10, 10, 10, Small +pulmonary veins in the right and left lung. 11, The left pulmonary +vein. 12, 12, The right pulmonary vein. + +Fig. 2. _An ideal View of the Pulmonary Circulation._ 1, 1, The right +lung. 2, 2, The left lung. 3, The trachea. 4, 4, 4, 4, 4, The right +bronchia. 5, 5, 5, 5, 5, The left bronchia. 6, 6, 6, 6, 6, 6, +Air-cells, with arteries and veins passing around them. 7, The right +auricle of the heart. 8, The right ventricle of the heart. 9, The +tricuspid valves. 10, The pulmonary artery. 11, 11, 11, 11, The right +pulmonary artery. 12, 12, 12, 12, 12, The left pulmonary artery. 13, +13, 13, 13, The right pulmonary vein. 14, 14, 14, 14, The left +pulmonary vein. 15, The left auricle. 16, The left ventricle. 17, The +mitral valves. 18, The septum between the right and left ventricles. + +Fig. 3. _An ideal View of the Capillaries._ 1, 1, A branch of the +pulmonary artery. 2, 2, A branch of the pulmonary vein. 3, 3, +Capillary vessels between the artery and vein. + +Fig. 4. _An ideal View of the Relations of the Bronchia, Air-cells, +Pulmonary Arteries, and Veins._ 1, A bronchial tube. 2, 2, 2, +Air-cells. 3, A branch of the pulmonary artery. 4, A branch of the +pulmonary vein. + + +PLATE VIII. + +THE CEREBRUM, CEREBELLUM, SPINAL CORD, AND NERVES + +1, The cerebrum. 2, The cerebellum. 3, 3, The spinal cord. 4, The +brachial plexus of nerves. 5, The lumbar plexus of nerves. 6, The +sacral plexus of nerves. 7, The facial nerve. 8, 17, The radial nerve. +9, 9, 16, The ulnar nerve. 10, The median nerve. G, The circumvex +nerve of the shoulder. + +11, 11, The great sciatic nerve. 12, The external popliteal, or +peroneal nerve. 13, 13, The posterior tibial nerve. 14, The external +tibial nerve. 15, The muscular branch of the external peroneal nerve. +18, The muscular branch of the sciatic nerve. P, Q, The posterior +tibial nerve. + +The letters and other figures indicate minor nervous filaments +distributed to the various muscles and the skin. + + +PLATE IX. + +THE SKIN. + +Fig. 1. _A perspiratory Tube and Gland._ 1, 1, The contorted portion +of the tube that forms the gland. 2, 2, Two branches which unite to +form the main duct of the gland. 3, 3, The perspiratory tube. 4, The +cuticle. 5. Its colored portion. 6, The cutis vera, (true skin.) 7, 7, +Fat vesicles, in which the gland is imbedded. + +Fig. 2. _A Papilla of the Skin._ 1, 1, Two papillae, formed of an +artery vein, and nerve. 2, 2, 2, 2, Nerves forming a loop in the +papillae. 3, 3, Arteries of the papillae. 4, 4, Veins of the papillae. 5, +5, A net-work of arteries, veins, and nerves. 6, 6, Nerves of the +skin. 8, 8, Arteries of the skin. 7, 7, Veins of the skin. + +Fig. 3. _A Hair, and its Oil-Glands._ 1, 1, The hair. 2, 2, The sheath +of the hair. 3, Oil-glands that surround the bulb of the hair, the +ducts of which open into the sheath of the hair, (2, 2.) + +Fig. 4. _A Section of the Skin._ 1, 1, The cuticle. 2, 2, Its colored +portion. 3, 3, The papillary layer. 4, 4, A net-work of arteries, +veins, and nerves, upon the upper surface of the cutis vera. 5, 5, 5, +5, The cutis vera, (true skin.) 6, 6, 6, Hairs that originate in the +cutis vera. 7, 7, 7, Oil-glands, the ducts of which connect with the +sheath of the hair. 8, 8, 8, 8, 8, 8, 8, 8, Perspiratory glands and +their ducts. 9, 9, 9, 9, 9, Nerves of the skin 10, 10, 10, 10, 10, +Arteries of the skin. 11, 11, 11, 11, 11, Veins of the skin. 12, 12, +12, 12, Papillae, or ridges of the skin. + + +PLATE X. + +AN ANTERO-POSTERIOR SECTION OF THE EYE. + +Fig. 1. 1, 1, The sclerotic coat. 2, 2, The cornea. 3, 3, The choroid +coat. 4, 4, The retina. 5, 5, The iris. 6, 6, The posterior chamber of +the eye that contains the aqueous humor. 7, 7, The anterior chamber. +8, 8, The pupil. 9, The crystalline humor. 10, 10, The vitreous humor +11, The optic nerve. 12, A representation of a pen. 13, An inverted +image of the pen (12) on the retina. 14, 14, A canal surrounding the +crystalline humor. 15, 15, The bevelled junction of the cornea and +sclerotic coats. A, a perpendicular ray of light from the pen. B, B, +oblique rays, that are refracted in passing through the humors of the +eye. + +Fig. 2. _A View of the External, Middle, and Internal Ear._ 1, 1, The +external ear. 2, The meatus auditorius externus, (the tube that +connects with the middle ear.) 3. The membrana tympani, (drum of the +ear.) 8, 8, The tympanum, (middle ear.) 4, The malleus. 5, The incus. +6, The orbicularis. 7, The stapes, (stirrup-bone,) that connects with +the vestibule of the internal ear. 9, 9, (4, 5, 6, 7, The small bones +of the middle ear,) 10, 11, 12, The semicircular canals. 13, 13, The +cochlea. 14, The auditory nerve. 15, The division of the auditory +nerve to the semicircular canals. 16, The division to the cochlea. 17, +17, The Eustachian tube. 18, The chorda tympani nerve. 19, The seventh +pair (facial) nerve. 20, The styloid process of the temporal bone. 21, +21, 21, 21, 21, The petrous or hard portion of the temporal bone, in +which the parts of the middle and internal ear are situated. + + + * * * * * + * * * * + * * * * * + + +Below is given the Title of a Book on a new plan, just published, +intended for beginners in the study of Physiology. + + + * * * * * + + +HUMAN AND COMPARATIVE + +ANATOMY, + +PHYSIOLOGY, AND HYGIENE + + +BY + +MRS. EUNICE P. CUTTER. + + +WITH ONE HUNDRED ENGRAVINGS. + + +NEW YORK: + +CLARK, AUSTIN, AND SMITH + +3 PARK ROW + + + + + +TEXT BOOKS + +UPON + +=Anatomy, Physiology, and Hygiene.= + +Recommended by the Hon. N. W. EDWARDS, School Sup't, Ill. + + +HUMAN AND COMPARATIVE ANATOMY, PHYSIOLOGY, AND HYGIENE. For District +Schools. With 100 Engravings. 132 pages. By MRS. EUNICE P. CUTTER. +Price 33 cts. + +This work contains full directions for the _study_ and _teaching_ +of Anatomy, Physiology, and Hygiene. This is a new feature. _Every +teacher would profit by it._ The plan of the work can be gathered from +the following _fac-simile_ of the table of contents:-- + +[Illustration: Fac-simile of the table of contents] + + + + + + * * * * * + + + + +Transcriber's note: + + +Typographical problems have been changed and are listed below. + +Author's archaic and variable spelling is mostly preserved. + +Author's punctuation style is mostly preserved. + +Passages in italics indicated by _underscores_. + +Passages in bold indicated by =equal signs=. + +In paragraph 97, '[s]' is used to represent the integral symbol. + +Greek words and letters have been transliterated and placed between ++marks+. + +This transcription is faithful to the original transliterations of +Greek (which occur in italics), even when they seem incorrect. + +Author's Greek transliterations included vowels with macrons. These +macrons have been changed to circumflexes in order to display +correctly in this text transcription. + +The original revision questions at the bottom of each page have been +set between lines that look like '-=-=-=-=-=-=-=-=-=-=-=-='. + +Footnotes have been placed directly below their relevant paragraphs. + + +Transcriber's changes: + + Title page: Was 'DESIGNER' (=DESIGNED= FOR) + + Title page: Was 'Massachuetts' (In the Clerk's Office of the + District Court of the District of =Massachusetts=.) + + Title page: Added '.' (No. 15 Vandewater Street, N. =Y.=) + + Page 18: Added ',' (_Example._ The digestive apparatus consists of + the =teeth,= stomach, liver, &c., all of which aid in the + digestion of food.) + + Page 23, Fig. 5: Added '.' (=Fig.= 5. A section of the femur, + (thigh-bone.) 1, 1, The extremities, showing a thin plate + of compact texture) + + Page 24: Was 'serious' (40. How does the mucous differ from the + =serous= tissue? What is the appearance of the external + surface of this membrane?) + + Page 27: Added comma (The most important compounds are _Al-bu'men_, + =_Fi'brin_,= _Gel'a-tin_) + + Page 27: Was 'organ ized (57. What are proximate elements? Do they + exist already formed in =organized= bodies? Name the most + important compounds.) + + Page 29: Added '.' (The earthy portion of the bones gives them + solidity and strength, while the animal part endows them + with =vitality.=) + + Page 33, Fig. 7: Added '.' (=7.= 1, 1, The coronal suture at the + front and upper part of the skull, or) + + Page 33, Fig. 7: Was 'cra nium' over line break. (suture at the + front and upper part of the skull, or =cranium=. 2, The + sagittal suture on the top of the skull.) + + Page 35, Fig. 9: Added '.' (=Fig.= 9. 1, The first bone of the + sternum, (breast-bone.) 2. The second bone of the + sternum.) + + Page 36: Added '.' (83. Describe the thorax. Explain fig. 9. 84. + Describe the =sternum.= 85. Describe the ribs.) + + Page 36: Added '?' (88. Give the structure of the vertebra. Where is + the spinal cord placed? 89. What is placed between each + =vertebra?= What is its use?) + + Page 37, Fig 10: Added '.' (5, The transverse =process.= 7, The + inferior articulating process.) + + Page 38, Fig 12: Added '.' (2, The sacrum. 3, The =coccyx.= 4, 4, + The acetabulum. a, a, The pubic portion) + + Page 38: Added '.' (In the adult? Describe the acetabulum. 93. + Describe the =sacrum.= Explain fig. 12. 94. Describe the + coccyx.) + + Page 41: Was 'out side' over page break (101. The RADIUS articulates + with the bones of the carpus and forms the wrist-joint. + This bone is situated on the =outside= of the fore-arm) + + Page 41, Fig. 16: Added '.' (11, 11, First range of finger-bones. + 12, 12, Second range of finger-bones. 13, 13, Third range + of =finger-bones.= 14, 15, Bones of the thumb.) + + Page 42: Was 'meta carpal' over line break. (and upon the other, the + first bone of the thumb. The five =metacarpal= bones + articulate with the second range of carpal bones.) + + Page 42: Added '.' (101. The radius. 102. How many bones in the + carpus? How are they ranged? =103.= Describe the) + + Page 42: Added '.' (103. Describe the =metacarpus.=) + + Page 42: Was 'sim ilar' over line break. (109. The FIBULA is a + smaller bone than the tibia, but of =similar= shape. It is + firmly bound to the tibia, at each extremity.) + + Page 43, Fig. 17: Added '.' (=Fig.= 17. 1, The shaft of the femur, + (thigh-bone.)) + + Page 44: Was 'a' (They articulate at one extremity with one range of + tarsal bones; =at= the other extremity, with the first + range of the toe-bones.) + + Page 45, Fig. 21: Added '.' (Fig. 21 The relative position of the + bones, cartilages, and synovial =membrane.= 1, 1, The + extremities of two bones that concur to form a joint.) + + Page 46: Added '.' (112. Describe the phalanges. 113-118. _Give the + anatomy of the =joints.=_ 113. What is said of the joints? + Of what are the joints composed?) + + Page 46: Added '?' (112. Describe the phalanges. 113-118. _Give the + anatomy of the joints._ 113. What is said of the joints? Of + what are the joints =composed?=) + + Page 52, Fig. 28: Added '.' (14, The hand. 15, The haunch-bone. 16, + The =sacrum.= 17, The hip-joint.) + + Page 52, Fig. 28: Added '.' (19, The patella. 20, The =knee-joint.= + 21, The fibula. 22, The tibia.) + + Page 65: Added '.' (150-160. _Give the anatomy of the =muscles.=_ + 150. What is said of the muscles? 151. Give their + structure.) + + Page 70, Fig. 39: Added '.' (Fig. =39.= A front view of the muscles + of the trunk.) + + Page 70, Fig. 39: Was 'superficia' (On the left side the + =superficial= layer is seen; on the right, the deep layer. + 1, The pectoralis major muscle.) + + Page 72, Fig. 41: Added '.' (Fig. 41 The first, second, and part of + the third layer of muscles of the =back.= The first layer + is shown on the right, and the second on the left side.) + + Page 72, Fig. 41: Added '.' (_Practical Explanation._ The muscles 1, + 11, 12, draw the scapula back toward the =spine.= The + muscles 11, 12, draw the scapula upward toward the head) + + Page 73, Fig. 42: Added '.' (Fig. 42. A representation of the under, + or abdominal side of the =diaphragm.= 1, 2, 3, 4, The + portion which is attached to the margin of the ribs.) + + Page 74, Fig. 43: Added '.' (=Fig.= 43. A front view of the + superficial layer of muscles of the fore-arm. 5, The flexor + carpi radialis muscle.) + + Page 74: Added '.' (That perform the delicate movements of the + fingers? Give the use of some of the muscles represented by + =fig.= 43. Those represented by fig. 44.) + + Page 81: Added '.' (The ball and socket joints, as the shoulder, are + not limited to mere flexion and =extension.= No joint in + the system has the range of movement that is) + + Page 84, Fig. 47: Added '.' (The muscles 9, fig. 46, and 6, =fig.= + 47, bend the neck forward. The muscles 3, 4, fig. 47, + elevate the head and chin.) + + Page 84, Fig. 47: Added '.' (The muscles 26, 27, 28, fig. 46, bend + the lower limbs on the body, at the =hip.= The muscle 28, + fig. 46, draws one leg over the other) + + Page 84, Fig. 47: Added '.' (The muscles 27, 28, =fig.= 47, extend + the lower limbs on the body, at the hip. The muscles 29, + 30, 31, fig. 46, extend the leg at the knee.) + + Page 84, Fig. 47: Added ',' (The muscles 27, 28, fig. =47,= extend + the lower limbs on the body, at the hip. The muscles 29, + 30, 31, fig. 46, extend the leg at the knee.) + + Page 84, Fig. 47: Added '.' (The muscles 27, 28, fig. 47, extend the + lower limbs on the body, at the =hip.= The muscles 29, 30, + 31, fig. 46, extend the leg at the knee.) + + Page 84, Fig. 47: Added '.' (The muscles 29, 30, fig. =47,= bend the + leg at the knee. The muscles 34, 36, fig. 46, bend the foot + at the ankle, and extend the toes.) + + Page 88: Added '?' (What class of pupils should have recesses most + =frequently?= 179. What effect has continued muscular + contraction?) + + Page 95: Added '.' (196. Give an instance of the different effects + produced by the absence and presence of the mental + =stimulus.=) + + Page 97, Fig. 49: Was '(1.' (the unnatural curved spinal column, and + its relative position to the perpendicular, =1.= The lower + limbs are curved at the knee) + + Page 98: Added comma. (In performing any labor, as in speaking, + reading, singing, mowing, sewing, =&c.,= there will be less + exhaustion) + + Page 100, Fig. 51: Added '.' (Fig. 51. An improper position in + =sitting.=) + + Page 104: Added ',' (210. What is said of the lateral and oblique + movements of the =arm,= hand, and fingers in writing? How + is this shown by experiment?) + + Page 107, Fig. 55: Added '.' (_d_, _e_, The bicuspids. _f_, _g_, The + molars, (double teeth.) _h_, The wisdom =teeth.=) + + Page 108, Fig. 56: Added '.' (=Fig.= 56. A side view of the body and + enamel of a front tooth.) + + Page 108, Fig. 57: Added '.' (=Fig.= 57. A side view of a molar + tooth. 1, The enamel. 2, The body of the tooth.) + + Page 108, Fig. 57: Added '.' (1, The enamel. 2, The body of the + =tooth.= 3, The cavity in the crown of the tooth that + contains the pulp.) + + Page 115, Fig. 59: Added '.' (=Fig.= 59. A side view of the face, + oesophagus, and trachea.) + + Page 118: Was 'COECUM' (249. The =CAECUM= is the blind pouch, or + cul-de-sac, at the commencement of the large intestine. + Attached to its extremity) + + Page 119: Was 'coecum' (is the mucous membrane sometimes called the + villous coat? 249. Describe the =caecum=.) + + Page 119, Fig. 61: Was 'coecum' (4, The appendix vermiformis. 5, The + =caecum=. 6, The ascending colon. 7, The transverse + colon.) + + Page 120: Was 'coecum' (half shorter than the intestine, and give it + a sacculated appearance, which is characteristic of the + =caecum= and colon.) + + Page 127: Moved up from the following box. (What is said in regard + to the bile? 266. What becomes of the chyle? =Of the + residuum?=) + + Page 128, Fig. 65: Added '.' (Fig. 65. An ideal view of the organs + of digestion, opened nearly the whole =length.=) + + Page 128, Fig. 65: Added '.' (1, The upper jaw. 2, The lower jaw. 3, + The tongue. 4, The roof of the =mouth.= 5, The oesophagus. + 6, The trachea. 7, The parotid gland.) + + Page 128, Fig. 65: Added '.' (8, The sublingual =gland.= 9, The + stomach. 10, 10, The liver. 11, The gall-cyst.) + + Page 128, Fig. 65: Added ',' (16, The opening of the small intestine + into the large intestine. 17, 18, 19, =20,= The large + intestine. 21, The spleen.) + + Page 128, Fig. 65: Added '.' (16, The opening of the small intestine + into the large intestine. 17, 18, 19, 20, The large + =intestine.= 21, The spleen.) + + Page 128, Fig. 65: Added '.' (21, The spleen. 22, The upper part of + the spinal =column.=) + + Page 129: Was 'prope' (The food that is well masticated, and has + blended with it a =proper= amount of saliva, will induce a + healthy action in the stomach.) + + Page 129: Added '.' (will induce a healthy action in the =stomach.= + Well-prepared chyme is the natural stimulus of the + duodenum,) + + Page 129: Added ',' (Well-prepared chyme is the natural stimulus of + the =duodenum,= liver, and pancreas; pure chyle is the + appropriate excitant of) + + Page 131: Added '.' (another demand for food. What effect has + increased exercise upon the system? =278.= How are the new + particles of matter supplied? What does this induce?) + + Page 143: Was 'There fore' over line break. (digested becomes mixed + with that last taken. =Therefore= the interval between + each meal should be) + + Page 145: Added '.' (312. Why should they not be taken cold? Show + some of the effects of improper food upon the inferior + =animals.=) + + Page 153: Added '.' (=327.= Why does the position of a person affect + digestion? 328. Into what are different kinds of aliment + separated?) + + Page 154: Added ',' (333. The CIRCULATORY ORGANS are the _Heart_, + =_Ar'te-ries_,= _Veins_, and _Cap'il-la-ries_.) + + Page 170, Fig. 75: Added '.' (=Fig.= 75. An ideal view of the + circulation in the lungs and system. From the right + ventricle of the heart) + + Page 179: Added '.' (the proper method of arresting the flow of + blood from divided arteries. 382. The second incident. + =383.= How should "flesh wounds" be dressed?) + + Page 182: Added '.' (What other vessels perform the office of + absorption? Give observation. 389. Describe the + =lymphatics.=) + + Page 186, Fig. 85: Added '.' (16, 17, 18, Of the face and neck. 19, + 20, Large =veins.= 21, The thoracic duct. 26, The + lymphatics of the heart.) + + Page 189: Added '.' (matter formed in the system of the diseased + person, may be more readily conveyed into their =own.=) + + Page 191: Was 'gen eral' over line. (every trifling and temporary + enlargement, or tumor, is a cancer. Their =general= remedy + is arsenic; and happy is the unfortunate sufferer) + + Page 191: Was 'suf ferer' over line. (arsenic; and happy is the + unfortunate =sufferer= who escapes destruction in their + hands, for too frequently) + + Page 191: Was 'frequent ly' over line. (happy is the unfortunate + sufferer who escapes destruction in their hands, for too + =frequently= their speedy cure is death.) + + Page 191: Was 'imme diately' over line. (413. In case of an + accidental wound, it is best =immediately= to bathe the + part thoroughly in pure water, and to) + + Page 192: Was 'Fol li-cles' (415. The SECRETORY ORGANS are the + _Ex-ha'lants_, =_Fol'li-cles_=, and the _Glands_.) + + Page 192, Fig. 86: Added '.' (Fig. 86. A secretory follicle. An + artery is seen, which supplies the material for its + =secretion.= Follicles are also supplied) + + Page 193: Was 'mys terious' over line. (420. SECRETION is one of the + most obscure and =mysterious= functions of the animal + economy. "It is that process) + + Page 194: Was 'secre tion' over line. (420-431. _Give the physiology + of the secretory organs._ 420. What is =secretion=?) + + Page 202: Was 'he' (Very soon, minute vessels shoot out from the + living parts into =the= coagulum of the blood, and + immediately commence their operations) + + Page 207: Added '?' (461. Mention another means by which the blood + may be made impure. How =remedied?= 462. What is the + effect of want of cleanliness upon the blood?) + + Page 208, Fig. 88: Added '.' (7, The right auricle of the heart. 8, + The left auricle. 9, The pulmonary artery. 10, The aorta. + 11, The vena cava =descendens.= 12, The trachea.) + + Page 208, Fig. 88: Added '.' (16, 16, The right and left lobe of the + liver. 17, The gall-cyst. 18, The =stomach.= 26, The + spleen. 19, 19, The duodenum.) + + Page 208, Fig. 88: Added '.' (19, 19, The duodenum. 20, The + ascending =colon.= 21, The transverse colon. 25, The + descending colon.) + + Page 211, Fig. 90: Added '.' (10, Its lower lobe. 11, The upper lobe + of the right =lung.= 12, The middle lobe. 13, The lower + lobe.) + + Page 218: Was 'cavicle' (Those which are attached to the upper rib, + sternum, and =clavicle=, contract and elevate the lower + and free extremities of the ribs.) + + Page 220, Fig. 96: Added '.' (5, 5, The position of the walls of the + abdomen in inspiration. 6, 6, The position of the + abdominal walls in =expiration.=) + + Page 223: Was 'cabonic' (In addition, there is a small amount of + vapor of water and =carbonic= acid. The pressure of this + invisible) + + Page 225, Fig. 98: Added '.' (Fig. 98. 1, A bronchial tube divided + into three branches. 2, 2, 2, =Air-cells.= 3, Branches of + the pulmonary artery, that spread over the air-cells.) + + Page 226: Added 'to' (In a few hours, the blood next =to= the + membrane will have become of a bright red color.) + + Page 227: Added '.' (reviewed from figs. 96, 97, and 99, or from + anatomical outline plates Nos. 5 and =7.=) + + Page 232: Added '.' (503. Mention some reasons why different persons + do not require the same amount of =air.=) + + Page 232: Added '.' (Give the illustration of the effects of impure + air on lighted =lamps.=) + + Page 237: Added '.' (to connect with the outer walls of the building + or external =air.= But if pure heated air is introduced + into the room, it obviates) + + Page 241: Added '.' (What does fig. 100 represent? Fig. 101? Give + observation =1st.=) + + Page 248: Added '.' (535. Mention some of the effects of mental + depression upon the =body.= What is related by Laennec?) + + Page 250: Was single-quote (Let another person press upon the + projecting part of the neck, called "Adam's =apple,"= + while air is introduced into the lungs through the + bellows.) + + Page 263: Changed '.' to '?' (persons that have broad chests and + voluminous lungs suffer less from cold than the + narrow-chested with small =lungs?=) + + Page 269: Added '.' (still broader behind, where it is connected + with the thyroid =cartilage.= Below, it connects with the + first ring of the trachea.) + + Page 271: Was 'glot tis' (The aperture, or opening between these + ligaments, is called the =_glot'tis_=, or _chink of the + glottis_.) + + Page 276: Added '.' (vocal organs are in action, will induce too + great a flow of blood to these parts, which will be + attended by subsequent =debility.=) + + Page 289, Fig. 115: Added '.' (These ducts open into the sheath of + the hair, (B.) All the figures, from 1 to 4, are magnified + thirty-eight =diameters.=) + + Page 294: Added ';' (A proper thickness of the cuticle is in this + manner =preserved;= the faculty of sensation and that of + touch are properly regulated;) + + Page 326: Added '?' (What causes the edge of the nail "to grow into + the flesh" of the =toe?= How prevented?) + + Page 329: Added '.' (731. What does the term brain designate? Name + =them.= How are they protected? Describe fig. 120.) + + Page 330, Fig. 121: Added '.' (Fig. =121.= A section of the + skull-bones and cerebrum. 1, 1, The skull.) + + Page 330, Fig. 121: Added '.' (1, 1, The skull. 2, 2, the dura + =mater.= 3, 3, The cineritious portion of the cerebrum.) + + Page 330, Fig. 121: Added '.' (3, 3, The cineritious portion of the + cerebrum. 4, 4, The medullary =portion.= The dark points + indicate the position of divided blood-vessels.) + + Page 332: Added '.' (=733.= Describe the appearance of the brain + when a horizontal section has been made. What is the gray + border often called? What connects the) + + Page 333, Fig. 123: Added '.' (4, 4, The optic foramen in the + sphenoid bone; through which passes the second pair of + =nerves.= 5, 5, The sphenoidal fissure.) + + Page 334, Fig. 124: Added '.' (5, The corpus callosum. 6, The first + pair of nerves. 7, The second =pair.= 8, The eye. 9, The + third pair of nerves.) + + Page 334: Added '.' (738. Describe the dura mater. What is its use? + Explain =fig.= 124.) + + Page 342: Added '.' (758. How many pairs of nerves issue from the + spinal cord? Explain =fig.= 128. Fig. 129.) + + Page 347: Was '13 1-2' (The heaviest brain on record was that of + Cuvier, which weighed 4 pounds and =13 1/2= ounces.) + + Page 365: Added '.' (what age particularly is excessive and + continued mental exertion hurtful? =813.= What is said of + scrofulous and rickety children?) + + Page 369: Added '.' (the more repose they =require.= The organs of + the child, beside sustaining their proper functions,) + + Page 385: Added '.' (868. What is the appearance of the surface of + the tongue? Explain =fig.= 134.) + + Page 387: Added '.' (papillae. 870. The fungiform papillae? What nerve + ramifies in the fungiform papillae? How can these papillae, + or points, be seen? =871-875.= _Give the physiology of the + organs of taste._ 871. Define taste.) + + Page 394: Added '.' (=892.= Describe the optic nerve. 893. Describe + the globe of the eye.) + + Page 394: Added '.' (892. Describe the optic =nerve.= 893. Describe + the globe of the eye.) + + Page 395, Fig. 137: Added '.' (7, 8, 9, 10, 11, 12, 13, The origin + of several pairs of cranial =nerves.=) + + Page 396: Added '.' (In form, it is circular, convexo-concave, and + resembles a =watch-glass.= It is received by its edge, + which is sharp and thin, within the) + + Page 397, Fig. 138: Added '.' (a transverse section of the globe of + the eye, seen from =within.= 1, The divided edge of the + three coats--sclerotic) + + Page 399, Fig. 139: Added '.' (The cornea (This connects with the + sclerotic coat by a bevelled edge.) 3, The choroid =coat.= + 6, 6, The iris. 7, The pupil.) + + Page 401: Added ',' (906. The PROTECTING ORGANS are the _Or'bits_, + =_Eyebrows_,= _Eyelids_, and _Lach'ry-mal Apparatus_.) + + Page 401: Added '.' (covered with short, thick hairs, which form the + upper boundary of the =orbits.= The eyebrows are so + arranged) + + Page 401: Added '.' (909. Describe the =eyelids.= What is the use of + the conjunctiva? How are the white spots frequently) + + Page 403: Added '.' (913. Describe the lachrymal =gland.= How many + ducts pass from this gland, and what do they convey to + the) + + Footnote 22: Added '.' (The refracting character of + differently-formed lenses is illustrated in the works on + Natural Philosophy, to which the pupil is =referred.=) + + Page 407, Fig. 142: Added '.' (Fig. 142. The forms of the different + lenses. 1, A plane lens. 2, A globe =lens.= 3, A + convexo-convex lens. 4, A plano-convex lens.) + + Page 407, Fig. 142: Added '.' (4, A plano-convex lens. 5, A + concavo-concave =lens.= 6, A plano-concave lens. 7, + Meniscus. 8, A concavo-convex lens.) + + Page 416: Changed '.' to '?' (Where is the wax of the ear + =secreted?= 948. Describe the membrana tympani.) + + Page 417: Was ', 1,' (This figure is highly magnified. =1, 1,= The + cochlea. 2, 3, Two channels, that wind two and a half + turns around a central point) + + Page 421: Was 'Eustuchian' (This is the result of the air in the + middle ear escaping through the =Eustachian= tube, when + the vibrations of the membrana tympani are violent.) + + Page 422: Added '.' (969. Many of the parts just enumerated aid in + hearing, but are not absolutely essential to this =sense.= + But if the vestibule) + + Page 422: Added '.' (_Note._ Let the anatomy and physiology of the + organs of hearing be reviewed, from fig. 148, or from + anatomical outline plate No. =10.=) + + Page 439: Added '.' (know the proper mode of procedure in such + cases, in order to render immediate assistance when within + his =power.=) + + Page 441: Added '.' (=1035.= What is the antidote? 1036. What should + immediately be done when arsenic is swallowed?) + + Page 441: Changed '.' to '?' (When magnesia cannot be obtained, what + will answer as a =substitute?= 1050. What is the antidote + when ley is swallowed?) + + Page 442: Changed '.' to '?' (What treatment should be adopted when + an over-dose of opium or any of its preparations is + =taken?= 1057. What is said of stramonium?) + + Page 443: Added '.' (lobelia, bloodroot, tobacco, &c., is taken? + =1062.= Should a physician be called in all cases when + poison is swallowed?) + + Page 444: Added '.' (CASEINE is abundantly found in milk. When + dried, it constitutes =cheese.= Alcohol, acids, and the + stomach of any of the mammalia coagulate it; and) + + Page 444: Added '.' (canal pass slowly through this portion. The + _rectum_ is named from the straight direction that it + assumes in the latter part of its =course.=) + + Page 445: Was 'a' (This is called the peristaltic, or vermicular + motion. The great length of intestine in =all= animals, + and especially in the herbivorous ones, is owing to the + necessity of) + + Page 448: Added '.' (and often inspiring more deeply than is common + in older =persons.= Also, if the carbon of the food does + not have a requisite supply of oxygen) + + Page 451: Added '.' (=AB-DUC'TOR.= [L. _abduco_ to lead away.] A + muscle which moves certain parts,) + + Page 452: Original looks like 'Arbor'. (AR'BOR. [L.] A tree. + _=Arbor= vitae._ The tree of life. A term applied to a + part) + + Page 452: Added ',' (BRE'VIS. [L.] _Brevis_, short; =_brevior_,= + shorter.) + + Page 452: Added ']' (CAP'IL-LA-RY. [L. _capillus_, a =hair.]= + Resembling a hair; small.) + + Page 454: Added '.' (Having the quality of exhaling or + =evaporating.=) + + Page 457: Added '.' (MI'TRAL. [=L.= _mitra_, a mitre.] The name of + the valves in the left side of) + + Page 458: Added '.' (=O-MEN'TUM.= [L.] The caul.) + + Page 458: Added '.' (=OP-PO'NENS.= That which acts in opposition to + something. The name of two) + + Page 458: Added '.' (OX-AL'IC. Pertaining to sorrel. _Oxalic acid_ + is the acid of =sorrel.= It is composed of two equivalents + of carbon) + + Page 458: Added '.' (invisible and inodorous. One of the components + of atmospheric =air.=) + + Page 458: Added '.' (PEC'TUS. [L.] The =chest.=) + + Page 458: Added '.' (PEC'TO-RAL. Pertaining to the =chest.=) + + Page 459: Added '.' (PLEX'US, [L. _plecto_, to weave =together.=] + Any union of nerves, vessels, or fibres,) + + Page 459: Added '.' (POS'TI-CUS. [L.] Behind; =posterior.= A term + applied to certain muscles.) + + Page 459: Added '.' (The muscle of the forearm that moves the palm + of the hand =downward.=) + + Page 460: Added '.' (=RA-DI-A'LIS.= Radial; belonging to the + radius.) + + Page 460: Added '.' (RA'MUS. [L.] A branch. A term applied to the + projections of =bones.=) + + Page 460: Added '.' (=SEP'TUM.= [L.] A membrane that divides two + cavities from each other.) + + Page 462: Was 'Be longing' over line. (VIT'RE-OUS. [L. _vitrum_, + glass.] =Belonging= to glass. A humor of the eye.) + + Page 462: Removed comma: was 'L.,' (VO'MER. [=L.= a ploughshare.] + One of the bones of the nose.) + + Page 464: Added ',' (=----,= Physiology of the, 164) + + Page 464: Added ',' (=----,= Hygiene of the, 172) + + Page 464: Added ',' (----, Influence =of,= on the Circulation, 173) + + Page 465: Added ',' (=MEDIASTINUM,= 211) + + Page 465: Added ',' (MEDULLA =OBLONGATA,= 333) + + Page 466: Added ',' (PRESERVATION OF =HEALTH,= 425) + + Page 466: Substituted 'Spinal' for the repeat line. (=SPINAL= CORD, + 36, 340) + + Page 467: Added comma (_Bones of the Head._ 7, The sphenoid bone. + =8,= The frontal bone. 10, The parietal bone. 11, The os + unguis. 12, The superior maxillary bone,) + + Page 468: Added ',' (41, 41, The bones of the =metatarsus,= (middle + of the foot.) 42, 42, The bones of the toes.) + + Page 469: Added '.' (27, 28, Ligaments that connect the clavicle + and =scapula.= 29, The capsular ligament of the + shoulder-joint.) + + Page 469: Added '.' (9, Tendon of the gluteus =muscle.= 35, The + capsular ligament of the hip-joint.) + + Page 469: Added '.' (37, The ligament that connects the tibia and + =fibula.= 38, The interosseous ligament.) + + Page 469: Added '.' (38, The interosseous ligament. 39, 40, + Ligaments of the =ankle-joint.=) + + Page 469: Added '.' (PLATE =III.=) + + Page 469: Added '.' (_Muscles of the Head and Neck._ 7, The + sterno-mastoideus =muscle.= 8, The sterno-hyoideus muscle. + 9, The omo-hyoideus muscle. 10, The) + + Page 469: Added '.' (16, The zygomatic muscle. 17, The depressor of + the lower =lip.= 18, The depressor anguli oris muscle. 19, + The triangular muscle of the) + + Page 469: Added '.' (43, The sartorius muscle. 44, The rectus + femoris muscle. 45, The vastus externus =muscle.= 46, The + vastus internus muscle.) + + Page 469: Added '.' (46, The vastus internus muscle. 47, The + internal straight =muscle.= 48. The pectineus muscle. 49, + The adductor muscle. 50, The psoas muscle.) + + Page 470: Added '.' (56, 57, The gastrocnemii muscles. 58, The long + flexor muscle of the great =toe.= 69, The short extensor + muscles of the toes.) + + Page 470: Added '.' (_Muscles of the Lower Extremities._ 29, The + gluteus maximus =muscle.= 30, The gluteus medius muscle. + 31, The biceps flexor cruris muscle.) + + Page 471: Added '.' (10, The pharynx. 11, The =oesophagus.= 12, The + upper portion of the spinal column. C, The spinal cord.) + + Page 471: Added '.' (1, 1, 1, An outline of the right lung. 2, 2, 2, + An outline of the left =lung.= 3, The larynx. 4, The + trachea.) + + Page 472: Added '.' (_Arteries of the Neck and =Head.=_ 15, The + right carotid artery. 16, The left carotid artery.) + + Page 472: Added '.' (The capillary vessels of the =lungs.= P, P, P, + The right pulmonary vein. Q, Q, The left pulmonary vein.) + + Page 473: Unclear in original (10, The median nerve. G, The + =circumvex= nerve of the shoulder.) + + Page 474: Added ',' (8, 8, =8,= 8, 8, 8, 8, 8, Perspiratory glands + and their ducts. 9, 9, 9, 9, 9, Nerves of the) + + Page 475: Added '.' (8, 8, The tympanum, (middle ear.) 4, The + =malleus.= 5, The incus. 6, The orbicularis.) + + + + + + +End of the Project Gutenberg EBook of A Treatise on Anatomy, Physiology, and +Hygiene (Revised Edition), by Calvin Cutter + +*** END OF THIS PROJECT GUTENBERG EBOOK TREATISE ON ANATOMY (REVISED) *** + +***** This file should be named 30541.txt or 30541.zip ***** +This and all associated files of various formats will be found in: + https://www.gutenberg.org/3/0/5/4/30541/ + +Produced by Bryan Ness, Dan Horwood and the Online +Distributed Proofreading Team at https://www.pgdp.net (This +file was produced from images generously made available +by The Internet Archive/American Libraries.) + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. Special rules, +set forth in the General Terms of Use part of this license, apply to +copying and distributing Project Gutenberg-tm electronic works to +protect the PROJECT GUTENBERG-tm concept and trademark. Project +Gutenberg is a registered trademark, and may not be used if you +charge for the eBooks, unless you receive specific permission. If you +do not charge anything for copies of this eBook, complying with the +rules is very easy. You may use this eBook for nearly any purpose +such as creation of derivative works, reports, performances and +research. They may be modified and printed and given away--you may do +practically ANYTHING with public domain eBooks. Redistribution is +subject to the trademark license, especially commercial +redistribution. + + + +*** START: FULL LICENSE *** + +THE FULL PROJECT GUTENBERG LICENSE +PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK + +To protect the Project Gutenberg-tm mission of promoting the free +distribution of electronic works, by using or distributing this work +(or any other work associated in any way with the phrase "Project +Gutenberg"), you agree to comply with all the terms of the Full Project +Gutenberg-tm License (available with this file or online at +https://gutenberg.org/license). + + +Section 1. General Terms of Use and Redistributing Project Gutenberg-tm +electronic works + +1.A. By reading or using any part of this Project Gutenberg-tm +electronic work, you indicate that you have read, understand, agree to +and accept all the terms of this license and intellectual property +(trademark/copyright) agreement. If you do not agree to abide by all +the terms of this agreement, you must cease using and return or destroy +all copies of Project Gutenberg-tm electronic works in your possession. +If you paid a fee for obtaining a copy of or access to a Project +Gutenberg-tm electronic work and you do not agree to be bound by the +terms of this agreement, you may obtain a refund from the person or +entity to whom you paid the fee as set forth in paragraph 1.E.8. + +1.B. "Project Gutenberg" is a registered trademark. It may only be +used on or associated in any way with an electronic work by people who +agree to be bound by the terms of this agreement. There are a few +things that you can do with most Project Gutenberg-tm electronic works +even without complying with the full terms of this agreement. See +paragraph 1.C below. There are a lot of things you can do with Project +Gutenberg-tm electronic works if you follow the terms of this agreement +and help preserve free future access to Project Gutenberg-tm electronic +works. See paragraph 1.E below. + +1.C. The Project Gutenberg Literary Archive Foundation ("the Foundation" +or PGLAF), owns a compilation copyright in the collection of Project +Gutenberg-tm electronic works. Nearly all the individual works in the +collection are in the public domain in the United States. If an +individual work is in the public domain in the United States and you are +located in the United States, we do not claim a right to prevent you from +copying, distributing, performing, displaying or creating derivative +works based on the work as long as all references to Project Gutenberg +are removed. Of course, we hope that you will support the Project +Gutenberg-tm mission of promoting free access to electronic works by +freely sharing Project Gutenberg-tm works in compliance with the terms of +this agreement for keeping the Project Gutenberg-tm name associated with +the work. You can easily comply with the terms of this agreement by +keeping this work in the same format with its attached full Project +Gutenberg-tm License when you share it without charge with others. + +1.D. The copyright laws of the place where you are located also govern +what you can do with this work. Copyright laws in most countries are in +a constant state of change. If you are outside the United States, check +the laws of your country in addition to the terms of this agreement +before downloading, copying, displaying, performing, distributing or +creating derivative works based on this work or any other Project +Gutenberg-tm work. The Foundation makes no representations concerning +the copyright status of any work in any country outside the United +States. + +1.E. Unless you have removed all references to Project Gutenberg: + +1.E.1. The following sentence, with active links to, or other immediate +access to, the full Project Gutenberg-tm License must appear prominently +whenever any copy of a Project Gutenberg-tm work (any work on which the +phrase "Project Gutenberg" appears, or with which the phrase "Project +Gutenberg" is associated) is accessed, displayed, performed, viewed, +copied or distributed: + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + +1.E.2. If an individual Project Gutenberg-tm electronic work is derived +from the public domain (does not contain a notice indicating that it is +posted with permission of the copyright holder), the work can be copied +and distributed to anyone in the United States without paying any fees +or charges. If you are redistributing or providing access to a work +with the phrase "Project Gutenberg" associated with or appearing on the +work, you must comply either with the requirements of paragraphs 1.E.1 +through 1.E.7 or obtain permission for the use of the work and the +Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or +1.E.9. + +1.E.3. If an individual Project Gutenberg-tm electronic work is posted +with the permission of the copyright holder, your use and distribution +must comply with both paragraphs 1.E.1 through 1.E.7 and any additional +terms imposed by the copyright holder. Additional terms will be linked +to the Project Gutenberg-tm License for all works posted with the +permission of the copyright holder found at the beginning of this work. + +1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm +License terms from this work, or any files containing a part of this +work or any other work associated with Project Gutenberg-tm. + +1.E.5. Do not copy, display, perform, distribute or redistribute this +electronic work, or any part of this electronic work, without +prominently displaying the sentence set forth in paragraph 1.E.1 with +active links or immediate access to the full terms of the Project +Gutenberg-tm License. + +1.E.6. You may convert to and distribute this work in any binary, +compressed, marked up, nonproprietary or proprietary form, including any +word processing or hypertext form. However, if you provide access to or +distribute copies of a Project Gutenberg-tm work in a format other than +"Plain Vanilla ASCII" or other format used in the official version +posted on the official Project Gutenberg-tm web site (www.gutenberg.org), +you must, at no additional cost, fee or expense to the user, provide a +copy, a means of exporting a copy, or a means of obtaining a copy upon +request, of the work in its original "Plain Vanilla ASCII" or other +form. Any alternate format must include the full Project Gutenberg-tm +License as specified in paragraph 1.E.1. + +1.E.7. Do not charge a fee for access to, viewing, displaying, +performing, copying or distributing any Project Gutenberg-tm works +unless you comply with paragraph 1.E.8 or 1.E.9. + +1.E.8. You may charge a reasonable fee for copies of or providing +access to or distributing Project Gutenberg-tm electronic works provided +that + +- You pay a royalty fee of 20% of the gross profits you derive from + the use of Project Gutenberg-tm works calculated using the method + you already use to calculate your applicable taxes. The fee is + owed to the owner of the Project Gutenberg-tm trademark, but he + has agreed to donate royalties under this paragraph to the + Project Gutenberg Literary Archive Foundation. Royalty payments + must be paid within 60 days following each date on which you + prepare (or are legally required to prepare) your periodic tax + returns. Royalty payments should be clearly marked as such and + sent to the Project Gutenberg Literary Archive Foundation at the + address specified in Section 4, "Information about donations to + the Project Gutenberg Literary Archive Foundation." + +- You provide a full refund of any money paid by a user who notifies + you in writing (or by e-mail) within 30 days of receipt that s/he + does not agree to the terms of the full Project Gutenberg-tm + License. You must require such a user to return or + destroy all copies of the works possessed in a physical medium + and discontinue all use of and all access to other copies of + Project Gutenberg-tm works. + +- You provide, in accordance with paragraph 1.F.3, a full refund of any + money paid for a work or a replacement copy, if a defect in the + electronic work is discovered and reported to you within 90 days + of receipt of the work. + +- You comply with all other terms of this agreement for free + distribution of Project Gutenberg-tm works. + +1.E.9. If you wish to charge a fee or distribute a Project Gutenberg-tm +electronic work or group of works on different terms than are set +forth in this agreement, you must obtain permission in writing from +both the Project Gutenberg Literary Archive Foundation and Michael +Hart, the owner of the Project Gutenberg-tm trademark. Contact the +Foundation as set forth in Section 3 below. + +1.F. + +1.F.1. Project Gutenberg volunteers and employees expend considerable +effort to identify, do copyright research on, transcribe and proofread +public domain works in creating the Project Gutenberg-tm +collection. Despite these efforts, Project Gutenberg-tm electronic +works, and the medium on which they may be stored, may contain +"Defects," such as, but not limited to, incomplete, inaccurate or +corrupt data, transcription errors, a copyright or other intellectual +property infringement, a defective or damaged disk or other medium, a +computer virus, or computer codes that damage or cannot be read by +your equipment. + +1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right +of Replacement or Refund" described in paragraph 1.F.3, the Project +Gutenberg Literary Archive Foundation, the owner of the Project +Gutenberg-tm trademark, and any other party distributing a Project +Gutenberg-tm electronic work under this agreement, disclaim all +liability to you for damages, costs and expenses, including legal +fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT +LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE +PROVIDED IN PARAGRAPH F3. YOU AGREE THAT THE FOUNDATION, THE +TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE +LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR +INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH +DAMAGE. + +1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a +defect in this electronic work within 90 days of receiving it, you can +receive a refund of the money (if any) you paid for it by sending a +written explanation to the person you received the work from. If you +received the work on a physical medium, you must return the medium with +your written explanation. The person or entity that provided you with +the defective work may elect to provide a replacement copy in lieu of a +refund. If you received the work electronically, the person or entity +providing it to you may choose to give you a second opportunity to +receive the work electronically in lieu of a refund. If the second copy +is also defective, you may demand a refund in writing without further +opportunities to fix the problem. + +1.F.4. Except for the limited right of replacement or refund set forth +in paragraph 1.F.3, this work is provided to you 'AS-IS' WITH NO OTHER +WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO +WARRANTIES OF MERCHANTIBILITY OR FITNESS FOR ANY PURPOSE. + +1.F.5. Some states do not allow disclaimers of certain implied +warranties or the exclusion or limitation of certain types of damages. +If any disclaimer or limitation set forth in this agreement violates the +law of the state applicable to this agreement, the agreement shall be +interpreted to make the maximum disclaimer or limitation permitted by +the applicable state law. The invalidity or unenforceability of any +provision of this agreement shall not void the remaining provisions. + +1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the +trademark owner, any agent or employee of the Foundation, anyone +providing copies of Project Gutenberg-tm electronic works in accordance +with this agreement, and any volunteers associated with the production, +promotion and distribution of Project Gutenberg-tm electronic works, +harmless from all liability, costs and expenses, including legal fees, +that arise directly or indirectly from any of the following which you do +or cause to occur: (a) distribution of this or any Project Gutenberg-tm +work, (b) alteration, modification, or additions or deletions to any +Project Gutenberg-tm work, and (c) any Defect you cause. + + +Section 2. Information about the Mission of Project Gutenberg-tm + +Project Gutenberg-tm is synonymous with the free distribution of +electronic works in formats readable by the widest variety of computers +including obsolete, old, middle-aged and new computers. It exists +because of the efforts of hundreds of volunteers and donations from +people in all walks of life. + +Volunteers and financial support to provide volunteers with the +assistance they need are critical to reaching Project Gutenberg-tm's +goals and ensuring that the Project Gutenberg-tm collection will +remain freely available for generations to come. In 2001, the Project +Gutenberg Literary Archive Foundation was created to provide a secure +and permanent future for Project Gutenberg-tm and future generations. +To learn more about the Project Gutenberg Literary Archive Foundation +and how your efforts and donations can help, see Sections 3 and 4 +and the Foundation web page at https://www.pglaf.org. + + +Section 3. Information about the Project Gutenberg Literary Archive +Foundation + +The Project Gutenberg Literary Archive Foundation is a non profit +501(c)(3) educational corporation organized under the laws of the +state of Mississippi and granted tax exempt status by the Internal +Revenue Service. The Foundation's EIN or federal tax identification +number is 64-6221541. Its 501(c)(3) letter is posted at +https://pglaf.org/fundraising. Contributions to the Project Gutenberg +Literary Archive Foundation are tax deductible to the full extent +permitted by U.S. federal laws and your state's laws. + +The Foundation's principal office is located at 4557 Melan Dr. S. +Fairbanks, AK, 99712., but its volunteers and employees are scattered +throughout numerous locations. Its business office is located at +809 North 1500 West, Salt Lake City, UT 84116, (801) 596-1887, email +business@pglaf.org. Email contact links and up to date contact +information can be found at the Foundation's web site and official +page at https://pglaf.org + +For additional contact information: + Dr. Gregory B. Newby + Chief Executive and Director + gbnewby@pglaf.org + + +Section 4. Information about Donations to the Project Gutenberg +Literary Archive Foundation + +Project Gutenberg-tm depends upon and cannot survive without wide +spread public support and donations to carry out its mission of +increasing the number of public domain and licensed works that can be +freely distributed in machine readable form accessible by the widest +array of equipment including outdated equipment. Many small donations +($1 to $5,000) are particularly important to maintaining tax exempt +status with the IRS. + +The Foundation is committed to complying with the laws regulating +charities and charitable donations in all 50 states of the United +States. Compliance requirements are not uniform and it takes a +considerable effort, much paperwork and many fees to meet and keep up +with these requirements. We do not solicit donations in locations +where we have not received written confirmation of compliance. To +SEND DONATIONS or determine the status of compliance for any +particular state visit https://pglaf.org + +While we cannot and do not solicit contributions from states where we +have not met the solicitation requirements, we know of no prohibition +against accepting unsolicited donations from donors in such states who +approach us with offers to donate. + +International donations are gratefully accepted, but we cannot make +any statements concerning tax treatment of donations received from +outside the United States. U.S. laws alone swamp our small staff. + +Please check the Project Gutenberg Web pages for current donation +methods and addresses. Donations are accepted in a number of other +ways including including checks, online payments and credit card +donations. To donate, please visit: https://pglaf.org/donate + + +Section 5. General Information About Project Gutenberg-tm electronic +works. + +Professor Michael S. Hart was the originator of the Project Gutenberg-tm +concept of a library of electronic works that could be freely shared +with anyone. For thirty years, he produced and distributed Project +Gutenberg-tm eBooks with only a loose network of volunteer support. + + +Project Gutenberg-tm eBooks are often created from several printed +editions, all of which are confirmed as Public Domain in the U.S. +unless a copyright notice is included. Thus, we do not necessarily +keep eBooks in compliance with any particular paper edition. + + +Most people start at our Web site which has the main PG search facility: + + https://www.gutenberg.org + +This Web site includes information about Project Gutenberg-tm, +including how to make donations to the Project Gutenberg Literary +Archive Foundation, how to help produce our new eBooks, and how to +subscribe to our email newsletter to hear about new eBooks. |