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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..d7b82bc --- /dev/null +++ b/.gitattributes @@ -0,0 +1,4 @@ +*.txt text eol=lf +*.htm text eol=lf +*.html text eol=lf +*.md text eol=lf diff --git a/LICENSE.txt b/LICENSE.txt new file mode 100644 index 0000000..6312041 --- /dev/null +++ b/LICENSE.txt @@ -0,0 +1,11 @@ +This eBook, including all associated images, markup, improvements, +metadata, and any other content or labor, has been confirmed to be +in the PUBLIC DOMAIN IN THE UNITED STATES. + +Procedures for determining public domain status are described in +the "Copyright How-To" at https://www.gutenberg.org. + +No investigation has been made concerning possible copyrights in +jurisdictions other than the United States. Anyone seeking to utilize +this eBook outside of the United States should confirm copyright +status under the laws that apply to them. diff --git a/README.md b/README.md new file mode 100644 index 0000000..08098f1 --- /dev/null +++ b/README.md @@ -0,0 +1,2 @@ +Project Gutenberg (https://www.gutenberg.org) public repository for +eBook #52987 (https://www.gutenberg.org/ebooks/52987) diff --git a/old/52987-0.txt b/old/52987-0.txt deleted file mode 100644 index 9a10fe1..0000000 --- a/old/52987-0.txt +++ /dev/null @@ -1,2010 +0,0 @@ -The Project Gutenberg EBook of Treatise on the Anatomy and Physiology of -the Mucous Membranes, by Xavier Bichat - -This eBook is for the use of anyone anywhere in the United States and most -other parts of the world 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. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - -Title: Treatise on the Anatomy and Physiology of the Mucous Membranes - With Illustrative Pathological Observations - -Author: Xavier Bichat - -Translator: Joseph Houlton - -Release Date: September 5, 2016 [EBook #52987] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK TREATISE ANATOMY OF MUCOUS MEMBRANES *** - - - - -Produced by Sonya Schermann, John Campbell and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - - - - - TRANSCRIBER'S NOTE - - Italic text is denoted by _underscores_. - - Obvious typographical errors and punctuation errors have been - corrected after careful comparison with other occurrences within - the text and consultation of external sources. - - More detail can be found at the end of the book. - - - - - A - - TREATISE - - ON - - THE ANATOMY AND PHYSIOLOGY - - OF THE - - Mucous Membranes; - - WITH - - ILLUSTRATIVE PATHOLOGICAL OBSERVATIONS. - - - _From the French_ - - OF - - XAVIER BICHAT. - - - BY JOSEPH HOULTON, - - MEMBER OF THE ROYAL COLLEGE OF SURGEONS IN LONDON. - - - LONDON: - - PRINTED FOR J. CALLOW, - - Medical Library, - - 16, PRINCES STREET, CORNER OF GERRARD STREET, SOHO. - - MDCCCXXI. - - - - -CHARLES WOOD, Printer, - -Poppin's Court, Fleet Street, London. - - - - -THE - -TRANSLATOR'S PREFACE. - - -The works of no medical writer deserve a more attentive perusal -than those of the illustrious BICHAT. Erudite, observant, and -industrious, he, at an early age, reared a monument of science, -which will perpetuate his name and matchless talents. From the -rich treasures he has left, the Translator presumes to present -this Treatise in an English costume. Where all is excellent it -is difficult to make a satisfactory selection; yet this portion -of the author's productions merits the particular attention of -medical students and practitioners in general, as it leads to the -knowledge of the structure and economy of that part of the animal -organization, which, more than any other, is subject to morbid -affections. - -The aim of the Translator has been faithfulness, clearness, and -conciseness, rather than elegance: how he has fulfilled his -intention he must leave to the decision of the candid Reader. - - SAFFRON WALDEN, - JULY 1, 1821. - - - - -CONTENTS. - - - SECT. PAGE - - I. _Of the Situation and Number of Mucous Membranes_ 1 - - II. _Of the Exterior Organization of Mucous Membranes_ 9 - - III. _Of the Interior Organization of Mucous Membranes_ 20 - - IV. _Of the Glands of Mucous Membranes_ 37 - - V. _Of the Vascular System of Mucous Membranes_ 54 - - VI. _Of the Variations in the Organization of Mucous Membranes_ 64 - - VII. _Of the Vital Powers of Mucous Membranes_ 70 - - VIII. _Of the Sympathies of Mucous Membranes_ 81 - - IX. _Of the Functions of Mucous Membranes_ 85 - - X. _Remarks on the Affections of Mucous Membranes_ 98 - - - - -A - -TREATISE - -ON - -MUCOUS MEMBRANES. - - - - -SECTION I. - -OF THE SITUATION AND NUMBER OF MUCOUS MEMBRANES. - - -1. The Mucous Membranes occupy the interior of those cavities, -which, by various openings, communicate with the skin. Their -number, at the first view, appears very considerable; for the -organs within which they are reflected are numerous. The stomach, -bladder, urethra, uterus, ureters, the intestines, &c., borrow from -these membranes a part of their structure: nevertheless, if it be -considered, that they are continuous throughout, that everywhere -they are observed to be extended from one organ to others, arising, -as they did at first, from the skin, their number will appear to -be singularly limited. In fact, in thus contemplating them, not as -insulated in each part, but as continued over various organs, it -will appear that they are reducible to two general surfaces. - -2. The first of these two surfaces, entering by the mouth, nose, -and anterior surface of the eye, (1) lines the first and second -of these cavities: from the first it extends into the excretory -ducts of the parotid and submaxillary glands; from the other it is -continued into all the sinuses, it forms the tunica conjunctiva, -descends by the puncta lacrymalia through the canal and lacrymal -sac to the nose. (2) It descends into the pharynx, and there -furnishes the inner surface of the Eustachian tube, and thence -it penetrates and lines the internal ear. (3) It sinks into the -trachea, and spreads itself over all the air passages. (4) It -enters the œsophagus and stomach. (5) It extends into the duodenum, -where it furnishes two branches, one destined to the ductus -communis choledochus, to the numerous rami of the hepatic duct, to -the cystic duct and gall bladder; the other to the pancreatic duct -and its various ramifications. (6) It is continued into the small -and large intestines, and finally terminates at the anus, where it -is identified with the skin. - -3. The second general mucous membrane enters, in men, by the -urethra, and thence spreads from one part through the bladder, -ureters, pelves, calices, papillæ, and uriniferous tubes; from the -other it sinks into the excretory ducts of the prostate gland, -into the ejaculatory ducts, the vesicula seminales, the vassa -defferentia, and the infinitely convoluted branches from which they -arise. In women, this membrane enters by the vulva, and from one -part penetrates the urethra, and is distributed, as in men, through -the urinary organs; from the other part it extends into the vagina, -which it lines, as it also does the uterus and the fallopian tubes, -and through the apertures at the extremities of these ducts it -comes in contact with the peritoneum. This is the only example -in the economy, of a communication between the mucous and serous -surfaces. - -4. This manner of describing the track of the mucous surfaces by -saying that they extend, sink, penetrate, &c., from one cavity -to another, is certainly not conformable to the march of nature, -which forms in each organ the membranes that belong to it, and -does not thus extend them from one to the other; but our manner -of conceiving is best accommodated by this language, of which the -least reflection will rectify the sense. - -5. In thus bringing all the mucous surfaces to two general -membranes, I am supported, not only by anatomical inspection, -but pathological observation also furnishes me with lines of -demarcation between the two, and with points of contact between -the different portions of the membranes of which each is the -assemblage. In the various sketches of epidemic catarrhs made -by authors, we frequently see one of these membranes has been -affected throughout its extent, whilst the other, on the contrary, -has remained untouched. It is not uncommon to observe a general -affection of the first, _viz._ that which extends from the mouth, -nose, and anterior surface of the eye, into the alimentary canal -and bronchi. The last epidemic observed at Paris, with which M. -Pinel was himself affected, bore this character: that of 1761, -described by Rayons, presented the same feature: that of 1732, -described in the Memoirs of the Edinburgh Society, was remarkable -for a like phenomenon. Now we do not see at the same time a -corresponding affection in the mucous membrane which spreads over -the organs of urine and of generation. Here is, therefore, (1) -an analogy between the different portions of the first, by the -uniformity of the affection; (2) a line of demarcation between -them, by the healthy state of the one and the disease of the other. - -6. We observe also, that irritation on any one point of these -membranes frequently produces a pain in another point of the same -membrane, which is not irritated; thus a stone in the bladder -causes a pain at the end of the glans, worms in the intestines -produce an itching at the nose, &c. &c. Now in these phenomena, -which are purely sympathetic, it is extremely rare that the partial -irritation of one of these two membranes produces a painful -affection in a part of the other. - -7. We ought, therefore, from inspection and observation, to -consider the mucous surface in general as formed by two grand -membranes, spread over several organs, and having no communication -with each other but by the skin, which is intermediate, and which, -being continuous with both, thus concurs with them to form a -general membrane, entire throughout, enveloping the exterior of the -animal, and extending to the interior over most of its essential -parts. It should seem, that there exists important relations -between the internal and external portions of this unique membrane, -and this we shall soon be shown by ulterior researches. - - - - -SECTION II. - -OF THE EXTERIOR ORGANIZATION OF MUCOUS MEMBRANES. - - -8. Every mucous membrane presents two surfaces; the one adhering -to the adjacent organs; the other free, beset with villosities, -and always moist with a mucous fluid: each of them deserves a -particular attention. - -9. The adherent surface is attached to muscles almost throughout -its extent. The mouth, the pharynx, the whole of the alimentary -canal, the bladder, the vagina, the uterus, and part of the -urethra, &c. present a muscular bed, embracing the exterior of -their mucous coat. In animals that have the panniculus carnosus, -this disposition perfectly coincides with that of the skin, which, -as we shall see, is in other respects analogous in structure -to mucous membranes. In man the cutaneous organ presents here -and there traces of this exterior muscle, as we observe in the -platysma myoides, the palmaris brevis, the occipito frontalis, in -most of the muscles of the face, &c. This disposition of mucous -membranes places them under the influence of those habitual changes -of contraction and dilatation, which are favourable to their -secretion, and various other functions. - -10. This muscular bed is not immediately inserted into the exterior -surface of the mucous membranes, but rather, according to Albinus, -into a dense layer of cellular tissue, which all the ancient -authors have denominated, in the stomach, intestines, and bladder, -the nervous coat; but when well examined it presents no character -analogous to that which the name indicates. The experiment of -inflation, by which it is brought into its primitive state, is not -so easy as Albinus and others have pretended; which led me to think -that its nature might not be cellular, but that it was probably -of a fibrous texture, formed by a web of extremely delicate and -scarcely visible tendons, offering points of origin and insertion -to all the fleshy fibres of the muscular bed, which, as we know, -never describe entire circles, but rather different segments of -that curve. I confess that this conjecture, though very likely, is -not founded upon any decisive and rigorous experiment. - -11. Whatever may be the nature of this intermediate membrane to -the mucous and muscular coats, it evidently has a dense, close -texture, which gives it a resistance very analogous to one of the -fibrous membranes. It is from this that the organ receives its -form; it is this which maintains and controls its shape, as may be -proved by the following experiment. Take a portion of intestine: -remove in any part of the bowel a part of this membrane, with the -serous and muscular membranes: having applied a ligature to the -inferior end, inflate it, the air will produce in the denuded part -an hernia of the mucous coat. Take another portion of intestine, -turn it, dissect off a small part of the mucous membrane and of -this coat: inflation will produce upon the serous and muscular -coats the same phenomenon as in the preceding case it did in the -mucous membrane. It is therefore to this intermediate tunic that -the mucous membrane owes its power of resistance to substances -which distend it. This applies equally to the stomach, bladder, -œsophagus, &c. - -12. The free surface of mucous membranes, or that which is -continually moistened by the fluid from which they borrow their -name, presents two kinds of wrinkles or folds, the one inherent -in their structure and which is constantly present, whatever may -be their state of contraction or dilatation, such as the pylorus, -the valvula conniventes, the valve of the colon, &c. These folds -are formed, not merely by the mucous membranes, but also by the -intermediate membrane mentioned above, and which in these parts -takes a remarkable density and thickness. - -13. The other folds may be called accidental, and are only observed -during the contraction of the organ; such are those of the inner -surface of the stomach, and of the large intestines, &c. In most -of the human subjects brought to our amphitheatres, these folds in -the stomach, of which so much has been said, are not perceptible, -because generally the subject has died of a disease which has -impaired the vital powers, without preventing all the action of -this viscus; so that, although it is frequently found empty, its -fibres are not in the least contracted. - -14. In experiments on living animals, on the contrary, these folds -are very apparent; and observe how they may be demonstrated. -Let a dog eat or drink copiously; open it immediately, and make -an incision into the stomach the whole length of its greater -curvature, no fold will then appear, but it soon contracts, its -edges are drawn in, and the whole of the mucous surface is covered -with numerous prominent plicæ in the form of circumvolutions. The -same result may be observed in the stomach of a recently killed -animal by distending it with air, and then opening it; or, what is -still better, by laying it open whilst empty, and stretching it, -the folds will disappear, and when we cease to make the extension -they immediately form again and are very apparent. - -15. I would observe on the subject of inflating the stomach, that -by distending it with oxygen gas the application of this fluid -does not produce more prominent folds, and therefore no stronger -contraction, than when carbonic acid gas is used for the same -purpose. This experiment presents a result very similar to what -I have observed when I have rendered animals emphysematous by -different æriform fluids. Frogs and Guinea pigs (these are the two -kinds I have chosen, the one being an animal of red and cold, and -the other of red and warm blood) presented very little difference -in their irritability, or their Galvanic susceptibility, whether -inflated with oxygen gas or with carbonic acid gas. They live very -well with this artificial emphysema, which gradually disappears. -Inflation with nitrous gas is always mortal, and its contact -appears to strike the muscles with atony. The stomach distended -with it very soon loses its power of contracting, and its folds -disappear. Here, as in all the experiments which have the vital -powers for their object, we frequently obtain very variable results. - -16. It follows, from what we have said respecting the folds of -mucous membranes, that in the contraction of the hollow organs, -which are lined by them, they suffer but a very trifling diminution -of surface, they scarcely contract at all, but fold themselves -within; so that in dissecting them upon their contracted organ, we -have an extent of surface nearly equal to that which they present -during its dilatation. This assertion, which is true concerning -the stomach, the œsophagus, and the intestines, is, perhaps, not -quite so as respects the bladder, whose contraction does not show -within such prominent folds, but they are sufficiently marked to -bring the mucous membrane of this organ under the general law. -It is, also, nearly the same with the gall bladder; yet we find -here another cause; observed alternately, in a state of hunger and -during digestion, it will be found to contain double the quantity -of bile in the former case that it does in the latter, as I have -had the opportunity of seeing in numerous instances, in experiments -made with this object in view, or with other intentions. Now, when -it has evacuated part of its contents it does not contract upon -the remainder of the bile, with the energy of the stomach when it -contains but little food, nor with the power of the bladder when -it contains but a small quantity of urine, but is then flaccid, -so that its distention or nondistention has but very trifling -influence upon the folds of its mucous membranes. - -17. Moreover, in saying that the mucous membranes present with -trifling variation the same extent of surface in the dilatations -as during the contraction of their respective organs, I intend to -speak of the ordinary state of the functions only, and not of those -enormous dilatations which are frequently seen in the stomach and -bladder, more rarely in the intestines. In such cases there is -doubtless a real extension, which in the membrane coincides with -that of the organ. - -18. One remarkable observation that the free surface of mucous -membranes affords us, and which I have already pointed out, -is, that this face is everywhere in contact with bodies of a -different nature to that of the animal: these bodies are either -introduced from without for its nourishment, and are not yet -assimilated to its substance, as we see in the alimentary canal -and in the trachea, or they are produced within, as we observe in -the excretory ducts of the glands, which all open into cavities -lined by mucous membranes, and discharge those particles, which, -after having for some time formed a part of the composition of -the solids, become heterogeneous to them, and are thrown off -by that habitual action of decomposition, which takes place in -living bodies. According to this observation we must consider the -mucous membranes as defensive coats, placed between our organs and -foreign bodies, and that they consequently serve the same purpose -internally which the skin does externally, as respects bodies that -are in contact with it. - - - - -SECTION III. - -OF THE INTERIOR ORGANIZATION OF MUCOUS MEMBRANES. - - -19. Between the mucous and other membranes, as respects their -interior organization, there is this essential difference, that -they are always formed by several thin fibrous layers; these layers -or coats are, with the exception of the rete mucosum, the same as -those which compose the skin with which these membranes have the -most exact analogy. We are about to examine separately each of -these layers, which are the epidermis, the corps papillaire, and -the chorion, in their general attributes; we shall afterwards -consider the particular modifications which they undergo in the -different parts of the mucous surfaces. - -20. All authors have admitted the epidermis of mucous membranes: -it appears, even, that the greatest part of them have believed -that it is merely that portion of the skin which descends into the -cavities to line them; Haller in particular is of this opinion; but -the least inspection is sufficient to show, that here, as in the -skin, it forms but a layer superficial to the corps papillaire and -chorion; boiling water, which detaches it from the surface of the -palate, the tongue, and even from the pharynx, leaves the two other -coats denuded and apparent. - -21. This epidermis is very distinct upon the glans, at the anus, at -the orifice of the urethra, at the entrances of the nasal fossæ, -and of the mouth, and in general wherever the mucous membranes -arise from the skin. It is demonstrated in these different places -by the frequent excoriations which occur on them; it may be raised -from the lips by a very fine lancet by the action of boiling water, -a hot iron, or even by epispastics, as the method of the ancients -proves, who employed them to produce a fresh raw surface for the -cure of the hare lip. - -22. But in proportion as we go into the depth of the mucous -membranes, the existence of this coat becomes more difficult to be -demonstrated; it cannot be raised by the finest instrument, nor -detached by boiling water, at least in the gall bladder, in the -stomach, and intestines. I have made these experiments in fresh -slain animals, and also in those where the natural heat had quite -left them. But what our experiments cannot effect, inflammations -will often produce. All the authors, who have written on the -affections of the organs which are lined by these membranes, -mention instances in which flakes, more or less considerable, have -been voided by the urethra, anus, mouth, nostrils, &c. Haller has -collected a great number of similar observations. Without doubt -the separation of the epidermis in these cases is produced nearly -in the same way as we observe it in cutaneous inflammations. In -many subjects that have died with symptoms of inflammation of the -mucous membranes, and which I have already had the opportunity of -dissecting, or of seeing dissected, I have not yet been able to -observe this separation going on; that is to say, the epidermis -separated at one point, and still remaining adherent at others, as -in erysipelas. I have tried in vain to produce this effect by the -application of an epispastic to the inner surface of the intestines -of a dog. - -23. This epidermis is subject, like that of the skin, to become -callous by pressure. Choppart cites a case of a shepherd, "dont -le canal de l'urètre présentoit cette disposition, à la suite de -l'introduction fréquemment répétée d'une petite baguette pour se -procurer des jouissances voluptueuses." We know the density that -this envelope takes in the stomachs of the gallinacea. In certain -circumstances, where the mucous membranes are protruded from -the body, as in prolapsus ani, inversion of the vagina, in the -artificial anus, &c., sometimes the pressure of the dress produces -in this epidermis a thickness evidently more considerable than is -natural to it. - -24. The epidermis is attached to the hair on the skin, although -it does not afford its immediate origin; sometimes also piliform -productions are observed in the mucous membranes. The bladder, the -stomach, the intestines, and the pituitary membrane have been in -various instances the seat of these unnatural excrescences: Haller -has cited various instances of them. - -25. This envelope appears to have upon the mucous surfaces the -same texture as on the skin, excepting in the delicacy of the -laminæ from which it is produced. It is to this delicacy, which -gives more exposure to the nerves, that we must doubtless refer -the facility with which we excite various remarkable modifications -in the sensibility, when by the Galvanic process we apply zinc to -the mucous surface of the conjunctiva, the pituitary membrane, the -internal membrane of the rectum, or of the gums, &c., and bring -these several metal plates into mediate or immediate contact. The -epidermis when removed is quickly reproduced; being destitute -of all kinds of sensibility, it in this respect serves the same -purpose as the skin, by guarding the very sensible corps papillaire -which is subjacent to it. To its presence over the mucous membranes -we must attribute the ability they have of being exposed to the -air, and even to the contact of foreign bodies, without excoriating -or inflaming, as is seen in cases of artificial anus, prolapsus -ani, &c., whilst serous and fibrous membranes never suffer such -exposure with impunity. Hence there is no danger, in this respect, -from opening the bladder: hence, on the contrary, that precept so -justly recommended, not to open the cavity of the peritoneum, and -to make the least possible incision into the synovial capsules. -I would observe, that the existence of the epidermis upon mucous -membranes is an important consideration, as respects the opinion -of those who, like Séguin, believing them to be without it, have -said, that contagion is always received by the lungs, and not by -the skin, which is, according to them, defended by this envelope. - -26. In the organization of the skin, immediately under the -epidermis is placed the corpus mucosum, particularly described by -Malpighi, and generally considered as the seat of colour in the -different varieties of the human species. It is described as a -coat, pierced with holes by the passage of the nervous papillæ: M. -Sabattier points out the manner of demonstrating it. Sömmering has, -it is said, seen it separated from the epidermis and chorion on the -scrotum of an Ethiopian. I confess that I have not yet been able to -perceive it: M. Portal does not appear to have been more fortunate. - -27. We distinguish only a kind of gelatinous juice intermediate -to the corps papillaire and epidermis, and most commonly it is -not even apparent; I have never been able to observe more with -certainty. In examining the skin of a Negro with attention, the -epidermis being detached, I have seen the external surface of the -chorion tinged with black, and that was all. Further, whatever -this corpus mucosum may be, it certainly does not exist in mucous -membranes, since they do not participate in the colour of the -integuments. The heat of the sun, which darkens these in white -people, does not appear to act upon the commencement of these -membranes, which are equally exposed with them to its influence, -as is seen in the red borders of the lips, &c. Nevertheless, I -have many times remarked on the palates of dogs, which have been -the subjects of my experiments, similar spots to those which have -marked their skin. - -28. The sensibility of the skin is principally owing to the corps -papillaire; that of the mucous membranes, exactly analogous to -that of the skin, appears to me to arise from the same cause. The -nervous papillæ of these membranes cannot be questioned: at their -origin, where they dip into the cavities, even in the commencement -of these cavities, as on the tongue, the palate, the internal -surface of the alæ nasi, on the glans, in the fossa naviculare, -on the inside of the lips, &c., inspection is sufficient to -demonstrate them. But, we ask, do these papillæ exist also in those -parts of mucous membranes which are more remote from the surface of -the body? Analogy answers in the affirmative, since sensibility is -the same there as at their origin; but inspection proves it in a -no less certain manner. I believe, that the villosities with which -we see them everywhere thickly furnished are nothing else than -these papillæ. - -29. Very different notions have been entertained concerning the -nature of these villosities: they have been considered, in the -œsophagus and in the stomach, as destined to the exhalation of the -gastric juice, in the intestines as serving for the absorption of -chyle, &c. But (1) It is difficult to conceive how an organ, so -nearly similar throughout its extent, should fulfil, in different -parts, such different functions; I say so nearly similar, because -we know, that the villosities of the small are more prominent than -those of the large intestines. (2) What would be the functions of -the villosities of the pituitary membrane, of the internal coat -of the urethra, and of the bladder, if they had no connection -with the sensibility of these membranes. (3) The microscopic -experiments so boasted of by Leiberkuhn, on the erection of the -intestinal villosities, have been contradicted by those of Hunter -and Cruikshank, and, above all, by those of Hewson. I can assert, -that I have never seen any thing of the kind on the surface of -the small intestines during the absorption of chyle, and yet it -appears to be a thing that cannot vary in different examinations. -(4) It is true that these intestinal villosities are everywhere -accompanied by a vascular web, which gives them a colour very -different from that of the cutaneous papillæ; but the nonappearance -of the cutaneous web is occasioned only by atmospherical pressure, -by means of the contraction that it produces in the minute vessels: -see, for instance, the newly-born infant; its cutaneous surface is -as red as that of its mucous membranes, and if the papillæ were a -little more elongated the skin would exactly resemble the internal -surface of the intestines: moreover, who does not know, that the -vascular web surrounding the papillæ is rendered so apparent by -fine injections as entirely to change the colour of the skin? - -30. That in the stomach this vascular web exhales the gastric -juice, and in the intestines it is interlaced with the origin of -the absorbents, so that they embrace the villosities, are facts -that we must admit, after the experiments and observations of the -anatomists, who in these times have been engaged with the lymphatic -system: but that does not contradict the assertion, that the bases -of these villosities are nervous, and perform the same functions -only on the mucous membrane as the papillæ do on the cutaneous -organ. This view of them, by explaining their existence as observed -generally over all the mucous surfaces, appears to me much more -conformable to the plan of nature than to suppose that they -perform, in their different parts, diverse and frequently opposite -functions. - -31. However, it is difficult to decide the question by ocular -observation; the tenuity of these prolongations conceals their -structure even from our microscopic instruments, a kind of agents -by which physiology and anatomy do not appear to me in other -respects ever to have obtained great assistance, because when parts -are so viewed each person sees in his own way, and is impressed -accordingly. It is therefore the observing of the vital functions -that should above all guide us. Now by judging of the villosities -in this way it appears evident, that they have the nature which -I have attributed to them. The following experiment will serve -to demonstrate the influence of the corps papillaire upon the -cutaneous sensibility: it succeeds also with mucous membranes. -If we remove any part of the epidermis, and irritate the corps -papillaire with a pointed instrument, the animal writhes, cries, -and gives signs of acute pain. If afterwards the cutis be pierced, -and with the instrument the internal surface of the chorion be -irritated, the animal will not appear to suffer pain, unless by -accident some nervous filaments should be touched. Thence it -follows very evidently, that the sensibility of the skin resides -in its external surface, that the nerves pass through the chorion -without being interwoven with its texture, and that their diffusion -only takes place on the corps papillaire. It is the same in mucous -surfaces. - -32. The length and form of the villosities vary in the different -mucous surfaces. Their appearance is not the same in the stomach, -the intestines, the bladder, the gall bladder, on the glans, &c.; -which variation exactly coincides with the sensibility peculiar to -each organ, a sensibility proved by numerous observations since -Bordeu, who was the first to direct the attention of physiologists -to the particular modifications that this property undergoes in the -different parts. - -33. Like the skin, the mucous membranes have their chorion: it is -thick on the palate, gums, and pituitary membrane, delicate in the -stomach and intestines, not very distinct in the bladder, gall -bladder, and excretory ducts. It appears to be formed of condensed -cellular strata, strongly united, as in the skin. Maceration -develops this texture in a very sensible manner. There is -nevertheless this difference, that in dropsy the cutaneous chorion -rises and resolves itself into distinct cellules, that become -filled with water, whilst no such change takes place in the mucous -chorion under similar circumstances. Does this difference in the -morbid state suppose a dissimilarity of structure? Certainly not; -for the synovial membrane is evidently of the same nature as the -serous membranes; and nevertheless it does not participate in the -hydropic diathesis which often affects them universally. It would -be curious to expose mucous membranes to the action of tan, to see -if they would present the same phenomena as the skin. - - - - -SECTION IV. - -OF THE GLANDS OF MUCOUS MEMBRANES. - - -34. Besides the three strata, which we have just mentioned, the -mucous membranes present in their structure a great number of -glands and blood vessels. The mucous glands exist in all membranes -which bear that appellation: they are situate under their chorion, -and even in its substance: they continually discharge, through -imperceptible orifices, a mucilaginous fluid, which lubricates -their free surface, and defends it from the impression of the -bodies with which it is in contact, at the same time that it -facilitates the passage of those substances. - -35. These glands, which are very apparent in the bronchi, palate, -œsophagus, and intestines, where they take the name of the -anatomists who have particularly described them, are less obvious -in the bladder, the gall bladder, uterus, vesiculæ seminales, -&c.; but the mucus which moistens the membranes unequivocally -demonstrates their existence. In fact, since this fluid is nearly -of the same nature on all the mucous surfaces, and, in those where -the glands are apparent, is evidently furnished by them, it must be -secreted in the same manner in those where they are less evident. -The identity of secreted fluids, certainly, supposes the identity -of the secreting organs. It should seem, that in situations -where these glands escape our observation, nature makes up for -their tenuity by increasing their number. In the lower animals, -particularly in the intestines, they form by their number a kind -of new layer, in addition to those we have described. The same may -be observed in the palate, velum, &c. in man. - -36. There is therefore this great difference between mucous and -serous membranes; that the fluid which lubricates the former is -furnished by secretion, whilst that which moistens the latter is -produced by exhalation. We know but little of the composition -of mucous fluids, because in the natural state it is difficult -to collect them, and in the morbid state, where their quantity -increases, as for instance in catarrhs, their composition probably -undergoes some alteration: but their functions in the animal -economy are well ascertained. - -37. The first of these functions is to defend the mucous membranes -from the impressions of the bodies with which they are in contact, -and which, as we have observed, are all heterogeneous to the -animal. Here, without doubt, we see the reason why the mucous -fluids are more abundant in the cavities where these bodies remain -for some time, as in the bladder, at the extremity of the rectum, -&c., than in those organs through which they merely pass, as in -the ureters, and in general in all the excretory ducts. Observe -again, why, when the impression of these bodies might be hurtful, -these fluids are poured out upon their surfaces in a much greater -quantity. The sound which is introduced into the urethra, and is -allowed to remain there; the instrument that is left in the vagina -to secure a polypus; that which, with a similar intention, remains -some time in the nasal fossæ; the canula, fixed in the lacrymal -sac, to remove the obstruction; and the tube that is introduced -into the œsophagus, when deglutition is interrupted, always -determine a more plentiful secretion upon the corresponding mucous -surface. This is one of the principal causes why it is so difficult -to retain elastic tubes in the trachea; the abundance of mucous -fluid, which is then separated, chokes up the apertures of the -instrument, and renders its frequent removal necessary, and may -even threaten the patient with suffocation, as Desault has himself -observed, although he has nevertheless many times succeeded with -that operation. - -38. It therefore appears, that every acute excitement of mucous -surfaces determines, in the corresponding glands, a remarkable -augmentation of action. But how can this excitement, which does -not take place immediately upon the glands, have so great an -influence over them? For, as we have said, these glands are always -subjacent to the membrane, and are consequently separated by it -from the irritating bodies. It appears that the above fact belongs -to a general modification of the glandular sensibility, which is -susceptible of being put into action by every irritation upon the -extremities of the excretory ducts, which will be proved by the -following considerations: (1) The presence of food in the mouth -produces a more abundant flow of saliva. (2) The catheter fixed -in the bladder, and irritating the ureters, or their vicinity, -increases the flow of urine. (3) The introduction of a bougie, but -half way up the urethra, will often be sufficient to occasion the -bladder to contract with a power equal to force the urine through -the passage, and so to overcome an obstruction in the canal. (4) -The irritation of the glans, and of the extremity of the urethra, -sub coitu, determines the contraction of the vesiculæ seminales, -and augments the secretory action of the testes. (5) The action -of an irritating fluid on the tunica conjunctiva occasions an -abundant flow of tears. (6) In making experiments upon the state -of the abdominal viscera during digestion, and under the influence -of hunger, I have observed, that whilst the food is only in the -stomach there is very little flow of bile; but it increases -when the aliment passes into the duodenum, so that then there -is a considerable quantity in the intestines. During hunger the -gall bladder is distended, and but little bile flows into the -intestines. At the end of digestion, and even when that process -is half finished, the gall bladder contains but half of its full -quantity; yet it might be expected to empty itself more easily -during abstinence, for then the bile it contains is of a deep -green colour, very bitter, very acrid, and likely to irritate the -organ which encloses it. On the contrary, during, or immediately -after digestion, it is more clear, mild, and less irritating; -there must, therefore, be, during digestion, another stimulus: now -this stimulus is the aliment passing over the mouth of the ductus -communis choledochus[A]. - -39. Let us conclude, from these numerous considerations, that one -of the principal means that nature employs to augment the action -of the glands, and to excite that of their excretory ducts, is -irritation upon the extremities of these ducts. We must refer to -that cause the abundant secretion and excretion of mucous fluids -in the cases above stated. It is also to this susceptibility of -the mucous glands, to be excited by irritation at the extremities -of their excretory ducts, that we must attribute the artificial -catarrhs which are occasioned by the respiration of chlorine -gas; the flow of mucus which attends a polypus, any tumour in -the vagina, stone in the bladder, &c. The frequent occurrence of -leuchorrhea in women who use coition immoderately, the abundant -flow of mucus from the noses of those persons who take snuff, in -all these cases there is evidently an irritation of the mouths of -the mucous ducts. - -40. The mucous membranes, by the continual secretion of which they -are the seat, perform a principal part in the animal economy. -They are to be regarded as one of the grand emunctories, by which -the residue of the nutriment constantly escapes from the body; -and consequently as one of the principal agents of that habitual -decomposition which carries away from living bodies the particles -which for some time formed part of the solids, but have at length -become heterogeneous to them. - -41. Remark the fact, that none of the mucous fluids enter into -the circulation, but are thrown out externally; that of the -bladder, ureters, and urethra, with the urine; that of the vesiculæ -seminales and of the vassa defferentia with the semen; that of -the nostrils by the action of blowing the nose; that of the mouth -partly by evaporation, and partly by the anus with the excrements; -that of the bronchi by the pulmonary exhalation, which is effected -principally by the solution of this mucous fluid in the air of -respiration; those of the œsophagus, of the stomach, of the -intestines, of the gall bladder, &c., with the excrements of which -they frequently form, in the ordinary state, a part nearly equal to -the residue of the aliment; and they even compose almost the whole -of the matter voided in certain dysenteries and fevers, where the -quantity is evidently disproportionate to the food that has been -taken. Let us observe on this subject, that in the analysis of the -fluids, in contact with the membranes of which we speak, as the -urine, bile, gastric juice, &c., there are always some errors, -because it is very difficult, impossible even, to separate them -from the mucous fluids. - -42. If we call to mind what has been said above, upon the extent -of the two general mucous surfaces, that they are equal and even -superior to the extent of the cutaneous organ; if we afterwards -contemplate these two grand surfaces, constantly throwing off the -mucous fluids, we shall see of what importance this evacuation -must be in the economy, and of what derangements its lesion may -become the source. It is doubtless to this law of nature, which -ordains that every mucous fluid shall be rejected externally, that -in the fœtus we must attribute the presence of the unctuous fluid, -of which the gall bladder is full, and of the meconium choking up -the intestines, &c., kinds of fluids which appear to be only a -collection of mucous juices, which, as they cannot be evacuated, -remain, until birth, upon the organs where they have been secreted. - -43. It is not the mucous fluids only that are rejected externally; -almost all the fluids, separated from the mass of blood by the -means of secretion, have the same destiny: this is evident in -the most considerable part of the bile. It is very probable, -also, that the saliva, the pancreatic juice, and the tears, are -discharged with the fæces, and that it is their want of colour -alone that prevents them from being distinguished like the bile. -I do not know even if, in reflecting on a crowd of phenomena, one -would not be tempted to establish, as a general principle, that no -fluid, separated by secretion, returns into the circulation; that -this destination belongs only to fluids separated by exhalation, -as those of the serous cavities, of the articulations, of the -medullary organ, &c.; that all the fluids are thus excremental or -recremental, and that there is no recremental excrement, as the -common division points out[B]. - -44. What is certain, at least, is, (1) that I have never been able -to effect the absorption of bile or saliva by the lymphatics. -When I have injected them into the cellular tissue of an animal -they have always produced inflammation and suppuration. (2) We -know that the urine, when infiltrated, does not become absorbed, -and that it strikes with death every part that it touches; whilst -the infiltrations of lymph, or of blood, are readily absorbed. -(3) There is an essential difference between the blood and the -secreted fluids as concerns their decomposition, whilst exhaled -fluids and serum, &c., are in that respect very similar. - - - - -SECTION V. - -OF THE VASCULAR SYSTEM OF MUCOUS MEMBRANES. - - -45. The mucous membranes receive a great number of vessels: the -remarkable redness which distinguishes them would be sufficient -to prove it to us, if it could not be demonstrated by injections. -This redness is not everywhere uniform; it is less in the bladder, -large intestines, and frontal sinuses; very marked in the stomach, -small intestines, and vagina, &c. It is produced by a web of -very numerous vessels, whose supplying branches, after having -passed through the chorion, finish on its surface by an infinite -division, embracing the corps papillaire, and is covered only by -the epidermis. - -46. It is the superficial position of these vessels that frequently -exposes them to hæmorrhages, as we remark principally in the nose, -and as is seen in hæmoptysis, hæmatemæsis, hæmaturia, in certain -dysenteries, where the blood escapes from the parieties of the -intestines, in uterine hæmorrhages, &c.; so that those spontaneous -hæmorrhages, which are independent of any external violence applied -to the open vessels, appear to be special affections of the mucous -membranes; they are seldom observed but in these organs, and they -form at least one of the grand characteristics which distinguishes -them from all the other membranes. - -47. It is also the superficial situation of the vascular system of -mucous membranes that renders their visible portions, as on the -lips, the glans, &c.; serviceable in showing us the state of the -circulation. Thus, in various kinds of asphyxia, in submersion, -strangulation, &c., these parts present a remarkable lividity; the -effect of the difficulty that the venous blood finds in passing -through the lungs, and of its reflux towards the surfaces where the -venous system arises from that of the arteries. - -48. I have already observed in the fœtus, and newly born infant, -that the vascular system is as apparent in the cutaneous organ -as in the mucous membranes; that the redness is there the same; -it is even in that part more marked in the earlier periods of -conception; but soon after birth all the redness of the skin seems -to concentrate itself upon the mucous membranes, which before, -being inactive, had no need of so considerable a circulation, but -which, becoming all at once the principal seat of the phenomena -of digestion, of the excretion of the bile, of the urine, of the -saliva, &c., demand a larger quantity of blood. The long continued -exposure of mucous membranes to the air frequently occasions them -to lose their characteristic redness, and they then assume the -colour of the skin (as M. Sabattier has well observed in treating -on prolapses of the uterus and vagina). By this circumstance some -have been deceived in believing such instances to be cases of -Hermaphrodism. - -49. An important question in the history of the vascular system of -the mucous membranes presents itself, which is, does this system -admit more or less blood, according to its various circumstances? -As the organs within which this sort of membrane is spread are -nearly all of them susceptible of contraction and dilatation, as -is observable in the stomach, intestines, bladder, &c., it has -been believed, that during their dilatation the vessels, being -more spread out, received more blood, and that during their -contraction, on the contrary, being folded on themselves, and as -it were strangulated, they admitted but a small portion of this -fluid, which then flows back into the adjacent organs. M. Chaussier -has applied these principles to the stomach, the circulation of -which he has considered as being alternately the inverse of that -of the omentum, which receives, during the vacuity of that organ, -the blood which it, being in a state of contraction, cannot admit. -Since M. Lieutaud, an analogous use has been attributed to the -spleen. Observe what I have ascertained on this subject from the -inspection of animals opened during abstinence, and in the various -periods of digestion. - -50. (1) Whilst the stomach is in a state of repletion its vessels -are more apparent on its exterior surface than during its vacuity; -its mucous surface at this time has no higher degree of redness, -but it has sometimes appeared to me to be less red than when the -viscus was empty. (2) The omentum, being less extended during -the plenitude of the stomach, presents nearly the same number of -apparent vessels, equal in length, but more folded upon themselves -than during the vacuity of that organ[C]. If they are then less -loaded with blood the difference is scarcely perceptible. I would -here observe, that great care is requisite in opening the animal, -or the blood will fall upon the omentum, and prevent us from -ascertaining its real state. (3) I am confident that there is no -such constant relation between the volume of the spleen and the -stomach in its different states of vacuity or plenitude; and if -that organ increases and diminishes under various circumstances, -it is not always in the inverse ratio of the state of the stomach. -Like Lieutaud, I at first made experiments on dogs, in order to -satisfy myself respecting the facts just stated; but the inequality -in the size and age of those which were brought to me leading -me to fear that I might not be able to compare their spleens -correctly, I repeated them on Guinea pigs, whose size and condition -corresponded, and examined, at the same time, some whilst the -stomach was empty, and others whilst it was full. I have almost -always found the volume of the spleen nearly equal, or at least the -difference has not been very perceptible. Nevertheless, in other -experiments I have seen the spleen, under various circumstances, -to show variations in its volume, but more particularly in weight; -and this was the same during digestion as after that process was -finished. From what has been said it appears, that if, whilst the -stomach is empty, there is a reflux of blood to the omentum and -spleen, it is less than has been commonly asserted. Moreover, -during this state of vacuity, the numerous folds of the mucous -membrane of this viscus leaving it, as we have before said, almost -as much extent of surface, and consequently of vessels, as during -its plenitude, the blood must circulate there nearly as freely as -when the viscus is in a contrary state; it has therefore no real -obstacles; the only impediment is in consequence of the tortuous -direction the vessels are then thrown into. Now this obstacle is -easily surmounted, since the vessels suffer no constriction or -diminution of calibre by the contraction of the stomach. - -51. As respects the other hollow organs, it is difficult to examine -the circulation of their adjacent viscera during their plenitude -or vacuity; for their vessels are not superficial, as in the -omentum, or insulated, as in the spleen; therefore, to decide -this question concerning them, we can only observe the state of -the mucous membranes upon their internal surface. Now they have -always appeared to me as red during the contraction as during the -dilatation of the organs. Finally, I give this only as a fact, -without pretending to draw any inference from it opposed to the -common opinion. It is, in fact, possible, that though the quantity -of blood be always nearly the same, the rapidity of the circulation -may increase; and consequently, in a given time, more of this -fluid will be sent there during the plenitude of the viscera. This -appears to be necessary for the secretion of the mucous fluids, -which are then more abundant. - - - - -SECTION VI. - -OF THE VARIATIONS IN THE ORGANIZATION OF MUCOUS MEMBRANES IN -DIFFERENT REGIONS. - - -52. The assemblage of the epidermis, corps papillaire, chorion, -glands, and vessels, constitutes in the mucous membranes their -intimate organization, which presents very considerable variations -in the different regions in which they are examined. I shall point -out only the principal of them; for in no different parts do these -membranes present the same appearance, and in order to describe all -their differences they should all be examined. - -53. One of these variations is that which the aspect of mucous -membranes presents at their origin, when compared with their -appearance in the more remote parts of the organs. Compare, for -instance, the surface of the glans, the inner surface of the -lips, the orifice of the urethra, &c., with any portion of the -inner surfaces of the stomach, intestines, &c. In the first the -corps papillaire will be seen slightly marked, and offering no -villous character, the epidermis thick, very distinct, and easily -separated, the chorion very evident, the vessels rather less -superficial, the mucous glands numerous and very large, more -especially in the mouth; in the other characters almost opposite -will be observed; we should say, that the mucous membranes have -at their origin a structure of a middle kind between the skin and -their deeper portions. - -54. Another variation of structure, not less striking, is that -which is met with in that portion of mucous surface which lines -the sinuses. Here it has more redness, and an extreme tenuity; -the three layers cannot be distinguished; and although there is a -considerable secretion of mucous fluids, there are no perceptible -mucous glands. Such are the characters of those portions of the -pituitary membrane, which are considered as adapted to augment the -sensation of smell, but which do not perform that function in the -manner generally understood. In fact, the instant when an odour -enters the nose, having the air for its vehicle, it cannot at once -pass into the sinuses, because the orifices by which these cavities -communicate with the nose are very small; but it enters gradually, -impregnates all the air which they contain, and not being able to -escape readily, for the same reason that rendered its entrance -difficult, the sensation is prolonged, which on the general -pituitary membrane is soon dissipated by the action of the fresh -air. Thus therefore the pituitary membrane is destined to receive -the impressions of odours, and its extensions into the cavities of -the sinuses to retain them. - -55. With regard to the particular structure of that portion of -mucous membrane which lines the sinuses I remark, that it is -absolutely the same as of that which is spread over the surface -of the internal ear, with the exception of a still more delicate -tissue. All anatomists call this membrane the periosteum of the -bony covering of the internal ear. The following considerations -prove that it is not a fibrous membrane, analogous to that which -covers the bones, but a mucous layer, like that of the sinuses. (1) -It is evidently seen to be a continuation of the pituitary membrane -by the medium of the Eustachian tube. (2) It is found to be -habitually moist with a mucous fluid, which is discharged through -that tube, a property foreign to fibrous membranes, both of whose -surfaces are always attached to some parts of the animal structure. -(3) No fibre can be distinguished in it. (4) Its spongy appearance, -though whitish, its softness, the readiness with which it gives way -to the least agent directed against it, with a view to tear it, -form a character not to be found in any part of the periosteum. - -56. I pass over the other variations of structure in mucous -membranes in their different regions; in all they have real -differences. I observe only, (1) That these variations distinguish -them from serous membranes, whose aspect is everywhere the same, as -may be seen by comparing the pericardium with the peritoneum, &c. -(2) The sensibility of mucous membranes varies in a very peculiar -manner in their different portions: thus an emetic irritates the -stomach, but not the conjunctiva; the pituitary membrane perceives -only odours; the mucous surface of the tongue flavours, &c. On the -contrary, the contact of all kinds of bodies with the naked serous -membranes produces phenomena exactly analogous. - - - - -SECTION VII. - -OF THE VITAL POWERS OF THE MUCOUS MEMBRANES. - - -57. The sensibility of mucous membranes is one of the principal -characteristics that distinguishes them from other analogous -organs. This power, which belongs to organic bodies, is variable -in every part, prompt to develop itself in some parts, under -the influence of the least excitement, roused with difficulty -in others, present in every part, liable to proceed by means -of inflammation from the most obscure state to the last degree -of intensity--this power is here remarkable for features very -analogous to those which it presents in the cutaneous surface (to -which, as we have stated, the mucous surface has great traits of -resemblance) as respects its structure. It is to this analogy of -sensibility that we must refer a crowd of phenomena, which are -alternately exhibited in an inverse order upon both surfaces. I -shall now point out some of these phenomena in succession. - -58. (1) When the temperature of the surrounding air deadens the -sensibility of the cutaneous organ, by contracting its tissue, the -sensibility of the mucous surface receives a remarkable increase -of energy. Observe why in winter, and in cold climates, where the -functions of the skin are singularly limited, all those of the -mucous membranes are in proportion augmented; thence arises a more -evident pulmonary exhalation, the internal secretions are more -abundant, digestion is more active and more ready to operate, -consequently the appetite is the more easily excited. (2) When, -on the contrary, the heat of the climate, or of the season, &c. -relaxes and opens the cutaneous surface, we should say, that the -mucous surface is in proportion constricted: during summer, in -the south, &c. there is a diminution in the internal secretions, -the urine for instance; a tardiness in the digestive phenomena -by a default in the actions of the stomach and intestines, and -the appetite is slow in returning. (3) The sudden suppression of -the functions of the cutaneous organ often determines a morbid -increase of action in those of the mucous membrane. Cold air, which -checks the perspiration, frequently produces colds and catarrhs, -affections which are marked by the sensibility and increased action -of the mucous glands. (4) In various affections of the mucous -membranes, baths, which relax and determine to the skin, produce -beneficial effects. - -59. The foregoing considerations evidently establish the influence, -which the vital powers of the skin have over those of the mucous -membranes. Others, not less important, demonstrate the reciprocal -dependence in which the skin is found with the same membranes, as -respects their vital powers. (1) During digestion, when the mucous -fluids are poured out in abundance into the stomach and intestines, -when, consequently, the mucous membranes of the alimentary canal -are in high action, the fluid of insensible perspiration is -evidently diminished, according to the observation of Santorius: -it is very small in quantity three hours after a meal, so that -the action of the cutaneous organ is visibly less energetic. (2) -During sleep, when all the internal functions become more marked -and are in full action, at which time the sensibility of the mucous -membranes is consequently highly excited, the skin appears to be -seized by a manifest debility--a debility, which is evinced by -the cold which it experiences when the animal reposes at night -uncovered, and by its want of susceptibility of various impressions. - -60. The sensibility of the mucous membranes, like that of the -cutaneous organ, is essentially submissive to the immense influence -of habit, which, tending incessantly to blunt the acuteness of the -sensations of which they are the seat, reduces the pain and the -pleasure that we receive through them equally to indifference, -which is, as some say, the middle state. - -61. I say, in the first place, that habit reduces the painful -sensations, which take place on mucous membranes, to indifference. -The presence of the catheter, which is passed up the urethra -for the first time, is cruel the first day, painful the second, -inconvenient the third, scarcely felt the fourth; pessaries -introduced into the vagina, bougies into the rectum, tents in the -nasal fossæ, the canula in the nasal canal, produce, in different -degrees, the same phenomena. It is upon this remark that is founded -the possibility of introducing instruments into the trachea to -aid respiration, and into the œsophagus to afford artificial -deglutition. This law of habit may even transform a painful into a -pleasant impression; of this fact the use of snuff, tobacco, and -various kinds of food, furnish us with remarkable examples. - -62. In the second place I observe, that habit produces indifference -to those sensations on the mucous membranes which were at first -agreeable. The perfumer placed in a fragrant atmosphere, and the -cook, whose palate is constantly affected by delicious flavours, do -not experience, in their professions, the exquisite pleasures that -they prepare for others. Habit may even change pleasant sensations -to painful ones, as in the preceding paragraph we saw it changed -painful to pleasing sensations. I observe, further, that this -remarkable influence of habit is exercised only over sensations -produced by simple contact, and not over those produced by real -lesion of the mucous membranes: thus it does not ameliorate the -pain produced by stone in the bladder, nor that which attends -polypus in the uterus. - -63. It is to this power of habit over the vital energies of -the mucous membranes that we must, in part, refer the gradual -diminution of their functions which accompanies advancing age. All -is susceptibility in the infant: in old age all is dull. In the one -the very active sensibility of the alimentary, biliary, urinary, -and salivary mucous surfaces, is that which principally produces -that rapidity with which the digestive and secretory phenomena -succeed each other. In the other this sensibility, weakened by the -habit of contact, does not so closely connect the same phenomena. - -64. Does not the following remarkable modification of the -sensibility of the mucous surfaces depend upon the same cause, -_viz._ that at their origin, as on the pituitary membrane, the -glans, the anus, &c., they give us the sensations of bodies with -which they are in contact, and that they do not produce this -sensation in the deeply seated organs which they line, as the -intestines, &c.? In the interior of these organs this contact is -always uniform; the bladder is in contact with the urine only, -the gall bladder with the bile, the stomach with the aliments -masticated and reduced to an homogeneous, pulpy paste, whatever -may be their diversity. This uniformity of sensation prevents -perception, because, in order to perceive, we must compare, and -here two terms of comparison are wanting. Thus the fœtus has no -sensation of the liquor amnii: the air is also very irritating at -first to the new-born infant, but at length it is not felt. On the -contrary, at the origins of mucous membranes exciting agents vary -every instant: the mind can, therefore, perceive their presence, -because it is able to establish relations between their various -modes of action. What I say is so true, that if in the interior of -the organs the mucous membranes be in contact with a foreign body -differing from that which is habitual to them, they transmit the -sensation of it to the mind; instruments introduced into bladder or -stomach are examples of it. Fresh air, which in very hot weather is -suddenly introduced into the trachea, causes an agreeable sensation -over the surface of the bronchi; but from habit we soon become -insensible to it, and the perception ceases. - -65. It is very difficult to point out with precision the character -of the tonic powers of mucous membranes, because, being almost in -every part united to a muscular layer, we can hardly distinguish -what belongs to the tonicity of the one from what depends upon the -irritability of the other; or otherwise, if the mucous membranes -be isolated, as in the nostrils, yet their attachment renders the -phenomena of their tonic powers very obscure. Nevertheless, the -action of the excretory ducts on their respective fluids, that -of the gall bladder, and of the vesiculæ seminales, which are -destitute of muscular attachments, and the spasmodic contraction -of the urethra, which sometimes takes place when the sound is -introduced, leave no doubt of the energy of this tonic power, -doubtless similar in its various modifications to that which is -observed in the cutaneous organ. - - - - -SECTION VIII. - -OF THE SYMPATHIES OF MUCOUS MEMBRANES. - - -66. I distribute the sympathies of mucous membranes, like those of -most of the other organs, into three general classes. In the first -class are ranked the sympathies in which irritation, on one part of -the mucous surface, produces a sensation in a distant part. A stone -in the bladder occasions pain at the end of glans; worms in the -intestines excite an itching at the nose. Whytt has seen a painful -affection induced over the whole side of the head by a foreign -body in the ear; an ulcer in the bladder produces a pain in the -superior parts of the thighs every time that the patient passes his -urine. - -67. I refer to the second class those sympathies in which the -irritation of one point on mucous surfaces produces irritability -in a different structure; thus, too lively an impression on the -pituitary membrane occasions sneezing; the irritation of the -bronchi coughing; biliary concretions produce spasmodic vomiting; -stones in the bladder occasion retraction of the testicle towards -the ring. In all these cases there is contraction of the muscles -produced by the irritation of the mucous surface, distant from the -place in which that contraction occurs. - -68. The last class of the sympathies of mucous membranes embraces -those in which the irritation of any part of their extension -determines elsewhere the exercise of their tonicity. Here we must -refer to what we have said upon glandular action being augmented -by the irritation of the extremities of the excretory ducts. Thus -it is evident, that the increase of the tonic power of the parotid -for the secretion of the saliva, and of its excretory duct in order -to transmit it, when the extremity of this duct is irritated by -food, sialogogue medicines, &c.,--it is evident, I say, that this -augmentation is a phenomenon purely sympathetic. We may designate -each of these three classes by the name of the vital power which -they bring into action, calling the first sympathy of sensibility; -the second, sympathy of irritability; and the third, sympathy of -tonicity. - -69. This manner of classing the sympathies is entirely borrowed -from the state of the vital powers, of which they are but irregular -modifications, and only aberrations, still unknown in their -nature. Nevertheless it is subject to very great inconveniences: -yet it appears to me to be preferable to that of Whytt, who simply -follows the order of the regions; and even to that of Barthy, who, -more methodical, examines them successively in the organs connected -by systems, in those which are insulated, and in those situated in -symmetrical halves of the body. - - - - -SECTION IX. - -OF THE FUNCTIONS OF MUCOUS MEMBRANES. - - -70. I have already examined many of the functions of mucous -membranes. I have considered them (1) As one of the grand -emunctories of the animal economy. (2) As performing the same -functions with respect to heterogeneous bodies, which may be within -our organs, as the skin does with regard to the bodies with which -it may be in contact. (3) As facilitating the passage of foreign -bodies by means of the mucous fluid by which they are lubricated. -It remains for me to examine three questions much agitated at -this time. (1) If the mucous membranes have any influence over the -redness of the blood. (2) If they exhale. (3) If the absorbents -arise from them; and if absorption consequently takes place there. - -71. The remarkable redness of these membranes, the analogy of -respiration, during which the blood becomes changed in colour -through the mucous surface of the bronchi, the well-known -experiment of a bladder filled with blood and placed in oxygen gas, -by which this fluid becomes also changed in colour,--have led to -the belief, that the blood, being separated from the atmospheric -air merely by a very fine pellicle on certain mucous surfaces, -as the pituitary membrane, the palatine, the glans, &c., would -there also take a brighter red colour, either by parting with a -portion of carbonic acid gas, or by combining with the oxygen of -the atmosphere, and that these membranes thus fulfilled functions -accessory to those of the lungs. The experiments of Jurine upon the -cutaneous organ, experiments adopted by many celebrated physicians, -appear also to favour the reality of that conjecture. - -72. Observe the experiment that I have tried, in order to ascertain -the validity of that fact. Through a wound in the abdomen I drew -out a portion of intestine, which I tied at one point. I then -returned it, keeping back a part, which I punctured, and introduced -into it sufficient atmospheric air to distend all that portion of -the bowel between the ligature and the orifice. I then confined the -air by another ligature, and reduced the whole. At the end of an -hour the animal was opened. I compared the blood of the mesenteric -veins, which arise from that portion of intestine distended by -air, with the blood of the other mesenteric veins arising from -the remainder of the canal: no difference of colour could be -observed: the internal surface of the inflated intestine did not -exhibit a brighter red. I expected to obtain a more marked effect -by repeating the same experiment on another animal with oxygen -gas, but I did not perceive any variation in the colour of the -blood. As on the mucous membranes, which are ordinarily in contact -with the air, this fluid is constantly renewed, and is agitated -by a perpetual movement, I tried to produce the same effect in -the intestines; for which purpose I made two openings into the -abdomen, through each of which I drew a portion of the intestinal -tube. I opened these two portions, adapting to one the tube of a -bladder filled with oxygen gas, and to the other that of an empty -bladder. I then pressed the full bladder so as to make the oxygen -gas pass into the empty one through the intermediate portion of -intestine which was in the abdomen, so that the warmth there might -encourage the circulation. The oxygen gas was in this manner sent -many times from one bladder to the other, making a current through -the intestine, which from its contraction was more difficult than -it at first appeared to be. The abdomen was then opened, but no -difference was found between the venous blood returning from that -portion of the intestine, and that which flowed from the other -parts of the canal. The superficial situation of the mesenteric -veins, which are covered by only a fine transparent lamina of -peritoneum, and their volume when the animal is not fat, render -these comparisons very easy to be made. - -73. I think, that from what occurs in the intestines we cannot -infer what takes place in the pituitary and palatine membranes, -&c.; because, although analogous, their organization may be -different. In these parts we cannot examine the venous blood -returning from them, as in the intestines: but, (1) If we consider, -that in animals, which have for some time respired oxygen gas, the -mucous membrane of the fauces does not exhibit any increase of -redness; (2) If we bear in mind, that the lividity of different -parts of this membrane, in those asphyxias which are produced by -carbonic acid gas, is not occasioned by the immediate contact of -this gas with the membranes, but by the reflux towards the surface, -of the venous blood which cannot pass through the heart, as occurs -in submersion, as demonstrated by Godwin, and as takes place in -all those cases in which the blood, previous to death, has found -difficulty in passing through the lungs; (3) If we remark lastly, -that in these circumstances the contact of the air, after death, -does not alter the lividity that the venous blood gives to the -mucous membranes, although the skin is then more permeable to -every kind of æriform fluid;--we shall see that we must at least -suspend our judgment, respecting the colouring of the blood through -mucous membranes, until farther observations shall have decided the -question. - -74. Observe another experiment, which may throw more light still -upon the subject. I have distended the peritoneal cavity of -different Guinea pigs with carbonic acid gas, with hydrogen gas, -with oxygen gas, and with atmospheric air, to see if I could -obtain, through a serous membrane, what I had not been able to -effect through a mucous surface. In these experiments I have found -no difference in the colour of the blood of the abdominal system: -it was the same as in fresh animals of the same kind, that I -always used to compare with those on which the experiments were -made. - -75. I believe, nevertheless, that I have observed many times, both -in frogs and in animals with warm and red blood, such as cats and -Guinea pigs, that the infiltration of oxygen gas into the cellular -tissue gives, after a certain time, a brighter colour to the blood -than this fluid presents in the artificial emphysemas which may -be produced by carbonic acid gas, hydrogen gas, or by atmospheric -air, in which circumstances the blood differs very little in colour -from its natural shade. But in other cases oxygen gas has had no -influence over the colour of the blood; so that, notwithstanding -the many experiments that have been made on this point, I cannot -state any general result. It appears, that the tonic powers of -the cellular tissue, and of the coats of the vessels which ramify -in it, receive a very varied influence from the contact of the -gases, and that, according to the nature of that influence, the -fibres contracting and becoming more or less firm render these -parts more or less permeable, both to the æriform fluids, which -have a tendency to escape from the blood to unite with that of the -emphysema, and to this last fluid, if it tends to combine with -the blood. This will doubtless explain the variations that I have -observed. - -76. Do the mucous surfaces exhale? The analogy of the skin would -seem to lead to the belief of it; for it appears well proved, that -the perspiration is not a transudation by the inorganic pores of -the cutaneous surface, but a true transmission by vessels of a -particular nature, and continuous with the arterial system. - -77. It appears, at first, that the pulmonary perspiration which -takes place on the surface of the bronchi, which has such -connection with that of the skin, which increases or diminishes -according to the decrease or augmentation of the other, and -of which the composition is apparently of the same nature--it -appears, I say, that the pulmonary perspiration is produced, at -least in part, by the system of exhalent vessels; and that if the -combination of the oxygen of the air concurs with the hydrogen of -the blood to produce it, during the act of respiration, it is but -in a very small quantity, and for that portion only which is purely -aqueous. It is necessary to observe further on this subject, that -the dissolution of the mucous fluid, which lubricates the bronchi, -in the air that is constantly inspired and expired, furnishes a -considerable portion of that vapour which rises from the lungs, and -which is insensible in summer, but very apparent in winter. - -78. The intestinal juice, that Haller has particularly considered, -but which appears to be less in quantity than he had estimated, -the gastric juice, and that of the œsophagus, are very probably -disposed of by way of exhalation on their respective mucous -surfaces; but in general it is very difficult to distinguish with -precision, in these organs, what belongs to the exhalent system -from what is furnished by the system of mucous glands, which, as we -have said, are everywhere subjacent to them. Thus we constantly see -the mucous fluids of the œsophagus, stomach, and intestines, mix -themselves with the other fluids of these parts. - -79. That mucous membranes absorb is evidently proved by the -absorption of the chyle upon the intestinal surfaces, of venereal -virus upon the glans and urethra, of variolous poison which is -sometimes rubbed upon the gums, of the serous portions of the -bile, of the urine, and of the semen, when they remain in their -respective reservoirs. When, from paralysis of the fleshy fibres -which terminate the rectum, the fæces accumulate at the extremity -of that intestine (a very common case in aged persons, and of which -Desault has cited many instances), these accumulations frequently -become hard, probably from the absorption of their juices, which -are obstructed there. We have many cases in which the urine has -been almost entirely absorbed by the mucous surface of the bladder, -when there has been absolute obstruction in the urethra. Whatever -may be the mode of this absorption, it appears that it is not -performed in a constant, uninterrupted manner, like that of the -serous membranes, in which the exhalent and absorbent systems are -in a continual alternate action; but that it occurs only under -certain circumstances, of which perhaps the greatest part are not -in the natural order of the functions. Finally, we have yet fewer -data respecting the mode of mucous absorption than on that of -cutaneous absorption: we confess it is very little understood, and -many even question its existence. - - - - -SECTION X. - -REMARKS ON THE AFFECTIONS OF MUCOUS MEMBRANES. - - -80. It is not my design to examine the affections of mucous -membranes; I shall notice only some phenomena, which in these -affections I believe deserve a particular attention, and the -explanation of which I propose to physiological physicians. - -81. Why do mucous membranes seldom contract adhesions from -inflammation, since that occurs so frequently in serous surfaces -under the same circumstances? Why does not the internal surface -of the inflamed stomach, intestines, or bladder, adhere in its -various portions like the pleura, tunica vaginalis, testis, &c. - -82. Why, in inflammations of mucous membranes, is there an abundant -flow of that fluid which habitually moistens them, and which -constitutes the different kinds of catarrhs, whilst the source of -the fluid that exhales from serous membranes is generally dried up -in analogous cases? - -83. Why do polypi, a kind of affection peculiar to mucous -membranes, seldom arise but at the origins of these membranes in -the vicinity of the skin, as in the nose, pharynx, vagina, &c., and -not in their more internal portions, as in the stomach, intestines, -&c.? Does this arise from the peculiarity of the texture that I -have shown mucous membranes to have in the vicinity of those places -where they arise from the skin, or must we attribute this fact to -the more numerous causes of irritation which act upon the origins -of these cavities? - -84. Are not aphthæ an isolated inflammatory affection of the glands -of the mucous membranes, whilst catarrhs are characterized by a -general inflammation of all the parts of these membranes? - - -THE END. - - -CHARLES WOOD, Printer, - -Poppin's Court, Fleet Street, London. - - - - -FOOTNOTES: - -[A] The following questions have been much disputed: Is there a -cystic and an hepatic bile? Is the one of a different nature from -the other? Does their quantity increase or vary? &c. Contrary, -and even opposite, opinions have been supported by numerous -experiments made upon living animals, as Haller as well observed. -These experiments, though at first sight contradictory, in reality -are not so, as I have had the opportunity of convincing myself, by -repeating them in the different stages of digestion, and during -the abstinence of the animal, which previously had never been done -with precision. The following are what I have observed in dogs -that I have used in my experiments. (1) During abstinence, the -stomach and the small intestines being empty, yellowish clear bile -was found in the hepatic duct and ductus communis choledochus; the -surface of the duodenum and jejunum were stained by a bile which -had the same appearance; the gall bladder was very much distended -by a greenish bitter bile, which was deeper in colour and more in -quantity, according to the length of the abstinence. (2) During the -gastric digestion, which may be prolonged for a sufficient length -of time by giving the dog large pieces of meat, which he swallows -without chewing, appearances were similar. (3) At the commencement -of intestinal digestion, the bile in the hepatic duct was always -found yellowish; that of the ductus communis choledochus deeper in -colour; the gall bladder not so full, and its bile becoming already -more clear. (4) Towards the end of digestion, and immediately -after it, the bile of the hepatic duct, of the ductus communis -choledochus, that contained in the gall bladder, and that which was -spread over the duodenum, were exactly of the same colour as the -common hepatic bile, a clear yellow, having but little bitterness. -The gall bladder was but half full; it was not contracted, but -flaccid. - -These observations, repeated a great number of times, evidently -prove, that such is the manner in which the bile flows during -abstinence and during digestion. (1) It appears that the liver is -continually separating from itself a sensible quantity of bile, -which increases during digestion. (2) That which is secreted during -abstinence is divided between the intestine, which is always found -coloured with it, and the gall bladder, which retains it without -transmitting any portion of it through the cystic duct, and where, -thus retained, it acquires a deeper colour and a character of -acrimony, necessary, without doubt, to the digestion which is soon -to follow. (3) When the food, having been digested by the stomach, -passes into the duodenum, then all the hepatic bile, which was -before divided, flows into the intestine, and even in greater -abundance; the gall bladder also pours that which it contains -upon the alimentary pulp, and with which it is then found quite -incorporated. (4) After the intestinal digestion the hepatic bile -diminishes, and begins to flow, part into the duodenum and part -into the gall bladder, where, being then examined, it is clear and -in small quantity, because it has not yet had time either to become -coloured, or to collect. - -There is, therefore, this difference between the two kinds of bile, -that the hepatic flows in a continual manner into the intestine, -and the cystic, during the absence of digestion, flows back into -the gall bladder; and whilst that function is going on it passes -towards the duodenum; or rather it is always the same fluid, of -which one part preserves the character it has when it leaves the -liver, and the other part undergoes a change in the gall bladder. -The difference of colour in the cystic bile, according to the time -that it has remained in the gall bladder, is analogous to the -colour of the urine, which becomes deeper as it is retained longer -in its receptacle. - -[B] The bile in the gall bladder, the urine in the bladder, and -the semen in the vesicula seminales, are certainly absorbed; but -it is not the fluid itself that re-enters the circulation, but -only its finest parts, some of its principles that we are not well -acquainted with, probably its aqueous or lymphatic portion. This -does not resemble the absorption in the pleura and other analogous -membranes, in which the fluid rejoins the blood in the same state -as it left it. - -[C] This is a necessary consequence of the disposition of the -vascular system of the stomach. The arteria coronaria ventriculi -superior being situated transversely between the stomach and the -omentum, and furnishing branches to both, it is evident, that when -the stomach, by separating the duplicatures of the omentum, lodges -itself between them, and this in applying itself over the stomach -becomes shortened, the branches that it receives from that artery -cannot in the same manner apply themselves to it. To effect this -it would be necessary, that they should proceed from the one to -the other without the intermediate trunk that cuts them at right -angles; then the stomach, by distending itself, would separate them -in the same way that it does the omentum, and would lodge between -them, instead of pushing them before it with their common trunk, -and folding them upon themselves. - - - - - TRANSCRIBER'S NOTE - - Italic text is denoted by _underscores_. - - Obvious typographical errors and punctuation errors have been - corrected after careful comparison with other occurrences within - the text and consultation of external sources. - - Except for those changes noted below, all misspellings in the text, - and inconsistent or archaic usage, have been retained. For example, - newly-born, newly born; circumvolutions; atmospherical. - - Pg v (TOC), page '101' replaced by '98'. - Pg 54, 'the mach, small' replaced by 'the stomach, small'. - Pg 57, 'membranes is spread' replaced by 'membrane is spread'. - Pg 81, 'OF THE SYMPATHY' replaced by 'OF THE SYMPATHIES'. - Pg 86, 'fine pelicle' replaced by 'fine pellicle'. - Pg 90, 'those asphyxies' replaced by 'those asphyxias'. - - - - - -End of the Project Gutenberg EBook of Treatise on the Anatomy and Physiology -of the Mucous Membranes, by Xavier Bichat - -*** END OF THIS PROJECT GUTENBERG EBOOK TREATISE ANATOMY OF MUCOUS MEMBRANES *** - -***** This file should be named 52987-0.txt or 52987-0.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/5/2/9/8/52987/ - -Produced by Sonya Schermann, John Campbell and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - -Updated editions will replace the previous one--the old editions will -be renamed. - -Creating the works from print editions not protected by U.S. copyright -law 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. 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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. If you are not located in the United States, you'll have -to check the laws of the country where you are located before using this ebook. - -Title: Treatise on the Anatomy and Physiology of the Mucous Membranes - With Illustrative Pathological Observations - -Author: Xavier Bichat - -Translator: Joseph Houlton - -Release Date: September 5, 2016 [EBook #52987] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK TREATISE ANATOMY OF MUCOUS MEMBRANES *** - - - - -Produced by Sonya Schermann, John Campbell and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - -</pre> - - - -<div class="transnote"> -<p><strong>TRANSCRIBER'S NOTE</strong></p> - -<p>Obvious typographical errors and punctuation errors have been -corrected after careful comparison with other occurrences within -the text and consultation of external sources.</p> - -<p class="customcover">The cover image was created by the transcriber -and is placed in the public domain.</p> - -<p>More detail can be found at <a href="#TN">the end of the book.</a></p> -</div> - - -<hr class="full pg-brk" /> - - -<h1> -<span class="small">A</span><br /> - -<span class="xxl lsp">TREATISE</span><br /> - -<span class="xxs">ON</span><br /> - -<span class="large">THE ANATOMY AND PHYSIOLOGY</span><br /> - -<span class="xxs">OF THE</span><br /> - -<span class="antiqua">Mucous Membranes;</span></h1> - - -<p class="pfs60">WITH</p> - -<p class="pfs90">ILLUSTRATIVE PATHOLOGICAL OBSERVATIONS.</p> - - -<p class="p2 pfs100"><em>From the French</em></p> - -<p class="pfs60">OF</p> - -<p class="pfs135 lsp">XAVIER BICHAT.</p> - -<hr class="r20" /> - -<p class="pfs120 lsp">BY JOSEPH HOULTON,</p> - -<p class="pfs60">MEMBER OF THE ROYAL COLLEGE OF SURGEONS IN LONDON.</p> - -<p class="p2" /> -<hr class="r30a" /> -<hr class="r30a5" /> - -<p class="p2 pfs100 lsp">LONDON:</p> - - -<p class="pfs100 lsp">PRINTED FOR J. CALLOW,</p> - -<p class="pfs90 antiqua">Medical Library,</p> - -<p class="p1 pfs60">16, PRINCES STREET, CORNER OF GERRARD STREET, SOHO.</p> - -<p class="pfs60">MDCCCXXI.</p> - - -<hr class="full pg-brk" /> - -<p class="p6" /> - -<p class="pfs80">CHARLES WOOD, Printer,<br /> -Poppin's Court, Fleet Street, London.</p> - - -<hr class="full" /> -<p><span class="pagenum"><a name="Page_iii" id="Page_iii">[Pg iii]</a></span></p> - -<h2><span class="medium">THE</span><br /><br /> -TRANSLATOR'S PREFACE.</h2> - -<p class="p2" /> -<hr class="r20a" /> -<hr class="r20a5" /> -<p class="p2" /> - -<div class="fs120"> -<p>The works of no medical writer deserve -a more attentive perusal than those of the -illustrious <span class="smcap">Bichat</span>. Erudite, observant, -and industrious, he, at an early age, reared -a monument of science, which will perpetuate -his name and matchless talents. -From the rich treasures he has left, the -Translator presumes to present this Treatise -in an English costume. Where -all is excellent it is difficult to make -a satisfactory selection; yet this portion -of the author's productions merits<span class="pagenum"><a name="Page_iv" id="Page_iv">[Pg iv]</a></span> -the particular attention of medical students -and practitioners in general, as it -leads to the knowledge of the structure -and economy of that part of the animal -organization, which, more than any other, -is subject to morbid affections.</p> - -<p>The aim of the Translator has been -faithfulness, clearness, and conciseness, -rather than elegance: how he has fulfilled -his intention he must leave to the decision -of the candid Reader.</p> -</div> - -<p class="p2"> -<span class="smcap">Saffron Walden,</span><br /> -<span class="smcap pad2">July 1, 1821.</span><br /> -</p> - - -<hr class="full" /> -<p><span class="pagenum"><a name="Page_v" id="Page_v">[Pg v]</a></span></p> - -<h2 class="lsp5 pad1"><a name="CONTENTS" id="CONTENTS">CONTENTS.</a></h2> - -<p class="p2" /> -<hr class="r20a" /> -<hr class="r20a5" /> -<p class="p2" /> - -<div class="center"> -<table border="0" cellpadding="4" cellspacing="4" width="95%" summary=""> -<tr class="xs"><td class="tdr">SECT.</td><td class="tdl"></td><td class="tdr">PAGE</td></tr> -<tr><td class="tdr">I.</td><td class="tdl"><em>Of the Situation and Number of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_1">1</a></td></tr> -<tr><td class="tdr">II.</td><td class="tdl"><em>Of the Exterior Organization of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_9">9</a></td></tr> -<tr><td class="tdr">III.</td><td class="tdl"><em>Of the Interior Organization of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_20">20</a></td></tr> -<tr><td class="tdr">IV.</td><td class="tdl"><em>Of the Glands of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_37">37</a></td></tr> -<tr><td class="tdr">V.</td><td class="tdl"><em>Of the Vascular System of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_54">54</a></td></tr> -<tr><td class="tdr">VI.</td><td class="tdl"><em>Of the Variations in the Organization of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_64">64</a></td></tr> -<tr><td class="tdr">VII.</td><td class="tdl"><em>Of the Vital Powers of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_70">70</a></td></tr> -<tr><td class="tdr">VIII.</td><td class="tdl"><em>Of the Sympathies of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_81">81</a></td></tr> -<tr><td class="tdr">IX.</td><td class="tdl"><em>Of the Functions of Mucous Membranes</em></td><td class="tdrb"><a href="#Page_85">85</a></td></tr> -<tr><td class="tdr">X.</td><td class="tdl"><em>Remarks on the Affections of Mucous Membranes</em></td><td class="tdrb"><ins class="corr" title="Transcriber's Note—Original text: '101'"><a href="#Page_98">98</a></ins></td></tr> -</table></div> - - -<hr class="chap pg-brk" /> -<p><span class="pagenum"><a name="Page_vi" id="Page_vi">[Pg vi]</a></span><br /> - <span class="pagenum"><a name="Page_1" id="Page_1">[Pg 1]</a></span></p> - -<p class="pfs100">A</p> - -<p class="p2 pfs150 lsp5">TREATISE</p> - -<p class="p4 pfs60">ON</p> - -<p class="p2 pfs150 lsp">MUCOUS MEMBRANES.</p> - -<div class="figcenter"> -<img src="images/sep.jpg" width="100" alt="" /> -</div> - - <div class="chapter"></div> - -<h2 class="no-brk"><a name="SECTION_I" id="SECTION_I"></a><a href="#CONTENTS">SECTION I.</a><br /><br /> - -<span class="small">OF THE SITUATION AND NUMBER OF -MUCOUS MEMBRANES.</span></h2> - - -<p>1. The Mucous Membranes occupy the -interior of those cavities, which, by various -openings, communicate with the skin. -Their number, at the first view, appears -very considerable; for the organs within -which they are reflected are numerous.<span class="pagenum"><a name="Page_2" id="Page_2">[2]</a></span> -The stomach, bladder, urethra, uterus, ureters, -the intestines, &c., borrow from these -membranes a part of their structure: nevertheless, -if it be considered, that they -are continuous throughout, that everywhere -they are observed to be extended -from one organ to others, arising, as they -did at first, from the skin, their number -will appear to be singularly limited. In -fact, in thus contemplating them, not as -insulated in each part, but as continued -over various organs, it will appear that -they are reducible to two general surfaces.</p> - -<p>2. The first of these two surfaces, entering -by the mouth, nose, and anterior -surface of the eye, (1) lines the first and -second of these cavities: from the first it -extends into the excretory ducts of the -parotid and submaxillary glands; from the -other it is continued into all the sinuses, -it forms the tunica conjunctiva, descends<span class="pagenum"><a name="Page_3" id="Page_3">[3]</a></span> -by the puncta lacrymalia through the canal -and lacrymal sac to the nose. (2) It -descends into the pharynx, and there -furnishes the inner surface of the Eustachian -tube, and thence it penetrates and -lines the internal ear. (3) It sinks into -the trachea, and spreads itself over all -the air passages. (4) It enters the œsophagus -and stomach. (5) It extends into -the duodenum, where it furnishes two -branches, one destined to the ductus -communis choledochus, to the numerous -rami of the hepatic duct, to the cystic -duct and gall bladder; the other to the -pancreatic duct and its various ramifications. -(6) It is continued into the small -and large intestines, and finally terminates -at the anus, where it is identified with the -skin.</p> - -<p>3. The second general mucous membrane -enters, in men, by the urethra, and -thence spreads from one part through the<span class="pagenum"><a name="Page_4" id="Page_4">[4]</a></span> -bladder, ureters, pelves, calices, papillæ, -and uriniferous tubes; from the other it -sinks into the excretory ducts of the -prostate gland, into the ejaculatory ducts, -the vesicula seminales, the vassa defferentia, -and the infinitely convoluted branches -from which they arise. In women, this -membrane enters by the vulva, and from -one part penetrates the urethra, and is -distributed, as in men, through the urinary -organs; from the other part it extends -into the vagina, which it lines, as it also -does the uterus and the fallopian tubes, -and through the apertures at the extremities -of these ducts it comes in contact -with the peritoneum. This is the only -example in the economy, of a communication -between the mucous and serous surfaces.</p> - -<p>4. This manner of describing the track -of the mucous surfaces by saying that -they extend, sink, penetrate, &c., from<span class="pagenum"><a name="Page_5" id="Page_5">[5]</a></span> -one cavity to another, is certainly not -conformable to the march of nature, which -forms in each organ the membranes that -belong to it, and does not thus extend -them from one to the other; but our -manner of conceiving is best accommodated -by this language, of which the least -reflection will rectify the sense.</p> - -<p>5. In thus bringing all the mucous surfaces -to two general membranes, I am -supported, not only by anatomical inspection, -but pathological observation also -furnishes me with lines of demarcation -between the two, and with points of contact -between the different portions of the -membranes of which each is the assemblage. -In the various sketches of epidemic -catarrhs made by authors, we frequently -see one of these membranes has -been affected throughout its extent, whilst -the other, on the contrary, has remained -untouched. It is not uncommon to observe<span class="pagenum"><a name="Page_6" id="Page_6">[6]</a></span> -a general affection of the first, <em>viz.</em> that -which extends from the mouth, nose, and -anterior surface of the eye, into the alimentary -canal and bronchi. The last -epidemic observed at Paris, with which -M. Pinel was himself affected, bore this -character: that of 1761, described by -Rayons, presented the same feature: that -of 1732, described in the Memoirs of the -Edinburgh Society, was remarkable for a -like phenomenon. Now we do not see at -the same time a corresponding affection in -the mucous membrane which spreads over -the organs of urine and of generation. -Here is, therefore, (1) an analogy between -the different portions of the first, by the -uniformity of the affection; (2) a line of -demarcation between them, by the healthy -state of the one and the disease of the -other.</p> - -<p>6. We observe also, that irritation on -any one point of these membranes fre<span class="pagenum"><a name="Page_7" id="Page_7">[7]</a></span>quently -produces a pain in another point -of the same membrane, which is not irritated; -thus a stone in the bladder causes -a pain at the end of the glans, worms in -the intestines produce an itching at the -nose, &c. &c. Now in these phenomena, -which are purely sympathetic, it is extremely -rare that the partial irritation of -one of these two membranes produces -a painful affection in a part of the other.</p> - -<p>7. We ought, therefore, from inspection -and observation, to consider the mucous -surface in general as formed by two grand -membranes, spread over several organs, -and having no communication with each -other but by the skin, which is intermediate, -and which, being continuous with -both, thus concurs with them to form a -general membrane, entire throughout, enveloping -the exterior of the animal, and -extending to the interior over most of its<span class="pagenum"><a name="Page_8" id="Page_8">[8]</a></span> -essential parts. It should seem, that there -exists important relations between the internal -and external portions of this unique -membrane, and this we shall soon be -shown by ulterior researches.</p> - - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_9" id="Page_9">[9]</a></span></p> -<p class="p4" /> - -<h2><a name="SECTION_II" id="SECTION_II"></a><a href="#CONTENTS">SECTION II.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small">OF THE EXTERIOR ORGANIZATION OF -MUCOUS MEMBRANES.</span></h2> - - -<p>8. Every mucous membrane presents -two surfaces; the one adhering to the -adjacent organs; the other free, beset -with villosities, and always moist with a -mucous fluid: each of them deserves a -particular attention.</p> - -<p>9. The adherent surface is attached to -muscles almost throughout its extent. -The mouth, the pharynx, the whole of -the alimentary canal, the bladder, the vagina, -the uterus, and part of the urethra, -&c. present a muscular bed, embracing<span class="pagenum"><a name="Page_10" id="Page_10">[10]</a></span> -the exterior of their mucous coat. In -animals that have the panniculus carnosus, -this disposition perfectly coincides -with that of the skin, which, as we shall -see, is in other respects analogous in -structure to mucous membranes. In man -the cutaneous organ presents here and -there traces of this exterior muscle, as we -observe in the platysma myoides, the palmaris -brevis, the occipito frontalis, in -most of the muscles of the face, &c. This -disposition of mucous membranes places -them under the influence of those habitual -changes of contraction and dilatation, -which are favourable to their secretion, -and various other functions.</p> - -<p>10. This muscular bed is not immediately -inserted into the exterior surface -of the mucous membranes, but rather, -according to Albinus, into a dense layer -of cellular tissue, which all the ancient -authors have denominated, in the stomach,<span class="pagenum"><a name="Page_11" id="Page_11">[11]</a></span> -intestines, and bladder, the nervous coat; -but when well examined it presents no -character analogous to that which the -name indicates. The experiment of inflation, -by which it is brought into its -primitive state, is not so easy as Albinus -and others have pretended; which led me -to think that its nature might not be cellular, -but that it was probably of a fibrous -texture, formed by a web of extremely -delicate and scarcely visible tendons, offering -points of origin and insertion to all -the fleshy fibres of the muscular bed, -which, as we know, never describe entire -circles, but rather different segments of -that curve. I confess that this conjecture, -though very likely, is not founded upon -any decisive and rigorous experiment.</p> - -<p>11. Whatever may be the nature of -this intermediate membrane to the mucous -and muscular coats, it evidently has<span class="pagenum"><a name="Page_12" id="Page_12">[12]</a></span> -a dense, close texture, which gives it a -resistance very analogous to one of the -fibrous membranes. It is from this that -the organ receives its form; it is this -which maintains and controls its shape, -as may be proved by the following experiment. -Take a portion of intestine: remove -in any part of the bowel a part of -this membrane, with the serous and muscular -membranes: having applied a ligature -to the inferior end, inflate it, the air -will produce in the denuded part an hernia -of the mucous coat. Take another -portion of intestine, turn it, dissect off a -small part of the mucous membrane and -of this coat: inflation will produce upon -the serous and muscular coats the same -phenomenon as in the preceding case it -did in the mucous membrane. It is therefore -to this intermediate tunic that the -mucous membrane owes its power of re<span class="pagenum"><a name="Page_13" id="Page_13">[13]</a></span>sistance -to substances which distend it. -This applies equally to the stomach, bladder, -œsophagus, &c.</p> - -<p>12. The free surface of mucous membranes, -or that which is continually moistened -by the fluid from which they borrow -their name, presents two kinds of wrinkles -or folds, the one inherent in their structure -and which is constantly present, -whatever may be their state of contraction -or dilatation, such as the pylorus, the -valvula conniventes, the valve of the -colon, &c. These folds are formed, not -merely by the mucous membranes, but -also by the intermediate membrane mentioned -above, and which in these parts -takes a remarkable density and thickness.</p> - -<p>13. The other folds may be called accidental, -and are only observed during -the contraction of the organ; such are -those of the inner surface of the stomach,<span class="pagenum"><a name="Page_14" id="Page_14">[14]</a></span> -and of the large intestines, &c. In most -of the human subjects brought to our -amphitheatres, these folds in the stomach, -of which so much has been said, -are not perceptible, because generally the -subject has died of a disease which has -impaired the vital powers, without preventing -all the action of this viscus; so -that, although it is frequently found empty, -its fibres are not in the least contracted.</p> - -<p>14. In experiments on living animals, -on the contrary, these folds are very apparent; -and observe how they may be demonstrated. -Let a dog eat or drink copiously; -open it immediately, and make -an incision into the stomach the whole -length of its greater curvature, no fold -will then appear, but it soon contracts, its -edges are drawn in, and the whole of the -mucous surface is covered with numerous -prominent plicæ in the form of circumvolutions. -The same result may be observed<span class="pagenum"><a name="Page_15" id="Page_15">[15]</a></span> -in the stomach of a recently killed animal -by distending it with air, and then opening -it; or, what is still better, by laying it -open whilst empty, and stretching it, the -folds will disappear, and when we cease -to make the extension they immediately -form again and are very apparent.</p> - -<p>15. I would observe on the subject of -inflating the stomach, that by distending -it with oxygen gas the application of this -fluid does not produce more prominent -folds, and therefore no stronger contraction, -than when carbonic acid gas is used -for the same purpose. This experiment -presents a result very similar to what I -have observed when I have rendered animals -emphysematous by different æriform -fluids. Frogs and Guinea pigs (these are -the two kinds I have chosen, the one being -an animal of red and cold, and the -other of red and warm blood) presented -very little difference in their irritability, or<span class="pagenum"><a name="Page_16" id="Page_16">[16]</a></span> -their Galvanic susceptibility, whether inflated -with oxygen gas or with carbonic -acid gas. They live very well with this -artificial emphysema, which gradually disappears. -Inflation with nitrous gas is always -mortal, and its contact appears to -strike the muscles with atony. The stomach -distended with it very soon loses -its power of contracting, and its folds disappear. -Here, as in all the experiments -which have the vital powers for their object, -we frequently obtain very variable -results.</p> - -<p>16. It follows, from what we have said -respecting the folds of mucous membranes, -that in the contraction of the hollow organs, -which are lined by them, they suffer -but a very trifling diminution of surface, -they scarcely contract at all, but fold -themselves within; so that in dissecting -them upon their contracted organ, we -have an extent of surface nearly equal to<span class="pagenum"><a name="Page_17" id="Page_17">[17]</a></span> -that which they present during its dilatation. -This assertion, which is true concerning -the stomach, the œsophagus, and -the intestines, is, perhaps, not quite so as -respects the bladder, whose contraction -does not show within such prominent -folds, but they are sufficiently marked to -bring the mucous membrane of this organ -under the general law. It is, also, nearly -the same with the gall bladder; yet we -find here another cause; observed alternately, -in a state of hunger and during digestion, -it will be found to contain double -the quantity of bile in the former case -that it does in the latter, as I have had -the opportunity of seeing in numerous instances, -in experiments made with this -object in view, or with other intentions. -Now, when it has evacuated part of its -contents it does not contract upon the remainder -of the bile, with the energy of -the stomach when it contains but little<span class="pagenum"><a name="Page_18" id="Page_18">[18]</a></span> -food, nor with the power of the bladder -when it contains but a small quantity of -urine, but is then flaccid, so that its distention -or nondistention has but very -trifling influence upon the folds of its mucous -membranes.</p> - -<p>17. Moreover, in saying that the mucous -membranes present with trifling variation -the same extent of surface in the dilatations -as during the contraction of their -respective organs, I intend to speak of -the ordinary state of the functions only, -and not of those enormous dilatations -which are frequently seen in the stomach -and bladder, more rarely in the intestines. -In such cases there is doubtless a real -extension, which in the membrane coincides -with that of the organ.</p> - -<p>18. One remarkable observation that the -free surface of mucous membranes affords -us, and which I have already pointed out, -is, that this face is everywhere in contact<span class="pagenum"><a name="Page_19" id="Page_19">[19]</a></span> -with bodies of a different nature to that of -the animal: these bodies are either introduced -from without for its nourishment, and -are not yet assimilated to its substance, as -we see in the alimentary canal and in the -trachea, or they are produced within, as -we observe in the excretory ducts of the -glands, which all open into cavities lined -by mucous membranes, and discharge -those particles, which, after having for -some time formed a part of the composition -of the solids, become heterogeneous -to them, and are thrown off by that habitual -action of decomposition, which -takes place in living bodies. According -to this observation we must consider the -mucous membranes as defensive coats, -placed between our organs and foreign -bodies, and that they consequently serve -the same purpose internally which the -skin does externally, as respects bodies -that are in contact with it.</p> - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_20" id="Page_20">[20]</a></span></p> -<p class="p4" /> - -<h2><a name="SECTION_III" id="SECTION_III"></a><a href="#CONTENTS">SECTION III.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small">OF THE INTERIOR ORGANIZATION OF -MUCOUS MEMBRANES.</span></h2> - - -<p>19. Between the mucous and other -membranes, as respects their interior organization, -there is this essential difference, -that they are always formed by -several thin fibrous layers; these layers -or coats are, with the exception of the -rete mucosum, the same as those which -compose the skin with which these membranes -have the most exact analogy. We -are about to examine separately each -of these layers, which are the epidermis, -the corps papillaire, and the chorion,<span class="pagenum"><a name="Page_21" id="Page_21">[21]</a></span> -in their general attributes; we shall afterwards -consider the particular modifications -which they undergo in the different parts -of the mucous surfaces.</p> - -<p>20. All authors have admitted the -epidermis of mucous membranes: it appears, -even, that the greatest part of -them have believed that it is merely -that portion of the skin which descends -into the cavities to line them; Haller -in particular is of this opinion; but the -least inspection is sufficient to show, that -here, as in the skin, it forms but a layer -superficial to the corps papillaire and -chorion; boiling water, which detaches -it from the surface of the palate, the -tongue, and even from the pharynx, -leaves the two other coats denuded and -apparent.</p> - -<p>21. This epidermis is very distinct upon -the glans, at the anus, at the orifice -of the urethra, at the entrances of the<span class="pagenum"><a name="Page_22" id="Page_22">[22]</a></span> -nasal fossæ, and of the mouth, and in -general wherever the mucous membranes -arise from the skin. It is demonstrated -in these different places by the frequent -excoriations which occur on them; it -may be raised from the lips by a very -fine lancet by the action of boiling water, -a hot iron, or even by epispastics, as -the method of the ancients proves, who -employed them to produce a fresh raw -surface for the cure of the hare lip.</p> - -<p>22. But in proportion as we go into -the depth of the mucous membranes, the -existence of this coat becomes more difficult -to be demonstrated; it cannot be -raised by the finest instrument, nor detached -by boiling water, at least in -the gall bladder, in the stomach, and -intestines. I have made these experiments -in fresh slain animals, and also -in those where the natural heat had -quite left them. But what our experi<span class="pagenum"><a name="Page_23" id="Page_23">[23]</a></span>ments -cannot effect, inflammations will -often produce. All the authors, who have -written on the affections of the organs -which are lined by these membranes, -mention instances in which flakes, more -or less considerable, have been voided -by the urethra, anus, mouth, nostrils, &c. -Haller has collected a great number of -similar observations. Without doubt the -separation of the epidermis in these cases -is produced nearly in the same way as -we observe it in cutaneous inflammations. -In many subjects that have died with -symptoms of inflammation of the mucous -membranes, and which I have already -had the opportunity of dissecting, or of -seeing dissected, I have not yet been able -to observe this separation going on; that -is to say, the epidermis separated at -one point, and still remaining adherent -at others, as in erysipelas. I have tried -in vain to produce this effect by the<span class="pagenum"><a name="Page_24" id="Page_24">[24]</a></span> -application of an epispastic to the inner -surface of the intestines of a dog.</p> - -<p>23. This epidermis is subject, like that -of the skin, to become callous by pressure. -Choppart cites a case of a shepherd, -"<span lang="fr" xml:lang="fr">dont le canal de l'urètre présentoit -cette disposition, à la suite de l'introduction -fréquemment répétée d'une petite -baguette pour se procurer des jouissances -voluptueuses</span>." We know the density -that this envelope takes in the stomachs -of the gallinacea. In certain circumstances, -where the mucous membranes -are protruded from the body, as in prolapsus -ani, inversion of the vagina, in the -artificial anus, &c., sometimes the pressure -of the dress produces in this epidermis -a thickness evidently more considerable -than is natural to it.</p> - -<p>24. The epidermis is attached to the -hair on the skin, although it does not -afford its immediate origin; sometimes<span class="pagenum"><a name="Page_25" id="Page_25">[25]</a></span> -also piliform productions are observed in -the mucous membranes. The bladder, -the stomach, the intestines, and the pituitary -membrane have been in various -instances the seat of these unnatural excrescences: -Haller has cited various instances -of them.</p> - -<p>25. This envelope appears to have upon -the mucous surfaces the same texture as -on the skin, excepting in the delicacy of -the laminæ from which it is produced. -It is to this delicacy, which gives more -exposure to the nerves, that we must -doubtless refer the facility with which -we excite various remarkable modifications -in the sensibility, when by the Galvanic -process we apply zinc to the mucous -surface of the conjunctiva, the pituitary -membrane, the internal membrane of the -rectum, or of the gums, &c., and bring -these several metal plates into mediate or -immediate contact. The epidermis when<span class="pagenum"><a name="Page_26" id="Page_26">[26]</a></span> -removed is quickly reproduced; being -destitute of all kinds of sensibility, it in -this respect serves the same purpose as -the skin, by guarding the very sensible -corps papillaire which is subjacent to it. -To its presence over the mucous membranes -we must attribute the ability they -have of being exposed to the air, and -even to the contact of foreign bodies, -without excoriating or inflaming, as is seen -in cases of artificial anus, prolapsus ani, -&c., whilst serous and fibrous membranes -never suffer such exposure with impunity. -Hence there is no danger, in this respect, -from opening the bladder: hence, on the -contrary, that precept so justly recommended, -not to open the cavity of the -peritoneum, and to make the least possible -incision into the synovial capsules. I -would observe, that the existence of the -epidermis upon mucous membranes is an -important consideration, as respects the<span class="pagenum"><a name="Page_27" id="Page_27">[27]</a></span> -opinion of those who, like Séguin, believing -them to be without it, have said, -that contagion is always received by the -lungs, and not by the skin, which is, according -to them, defended by this envelope.</p> - -<p>26. In the organization of the skin, -immediately under the epidermis is placed -the corpus mucosum, particularly described -by Malpighi, and generally considered -as the seat of colour in the different -varieties of the human species. It -is described as a coat, pierced with holes -by the passage of the nervous papillæ: -M. Sabattier points out the manner of -demonstrating it. Sömmering has, it is -said, seen it separated from the epidermis -and chorion on the scrotum of an Ethiopian. -I confess that I have not yet been -able to perceive it: M. Portal does not -appear to have been more fortunate.</p> - -<p><span class="pagenum"><a name="Page_28" id="Page_28">[28]</a></span></p> - -<p>27. We distinguish only a kind of gelatinous -juice intermediate to the corps -papillaire and epidermis, and most commonly -it is not even apparent; I have -never been able to observe more with -certainty. In examining the skin of a -Negro with attention, the epidermis being -detached, I have seen the external surface -of the chorion tinged with black, and that -was all. Further, whatever this corpus -mucosum may be, it certainly does not -exist in mucous membranes, since they -do not participate in the colour of the -integuments. The heat of the sun, which -darkens these in white people, does not -appear to act upon the commencement -of these membranes, which are equally -exposed with them to its influence, as -is seen in the red borders of the lips, &c. -Nevertheless, I have many times remarked -on the palates of dogs, which have been<span class="pagenum"><a name="Page_29" id="Page_29">[29]</a></span> -the subjects of my experiments, similar -spots to those which have marked their -skin.</p> - -<p>28. The sensibility of the skin is principally -owing to the corps papillaire; that -of the mucous membranes, exactly analogous -to that of the skin, appears to me -to arise from the same cause. The nervous -papillæ of these membranes cannot -be questioned: at their origin, where they -dip into the cavities, even in the commencement -of these cavities, as on the -tongue, the palate, the internal surface -of the alæ nasi, on the glans, in the fossa -naviculare, on the inside of the lips, &c., -inspection is sufficient to demonstrate -them. But, we ask, do these papillæ -exist also in those parts of mucous membranes -which are more remote from the -surface of the body? Analogy answers -in the affirmative, since sensibility is the -same there as at their origin; but inspec<span class="pagenum"><a name="Page_30" id="Page_30">[30]</a></span>tion -proves it in a no less certain manner. -I believe, that the villosities with which -we see them everywhere thickly furnished -are nothing else than these papillæ.</p> - -<p>29. Very different notions have been -entertained concerning the nature of these -villosities: they have been considered, in -the œsophagus and in the stomach, as -destined to the exhalation of the gastric -juice, in the intestines as serving for the -absorption of chyle, &c. But (1) It is -difficult to conceive how an organ, so -nearly similar throughout its extent, should -fulfil, in different parts, such different -functions; I say so nearly similar, because -we know, that the villosities of the small -are more prominent than those of the -large intestines. (2) What would be the -functions of the villosities of the pituitary -membrane, of the internal coat of the -urethra, and of the bladder, if they had -no connection with the sensibility of these<span class="pagenum"><a name="Page_31" id="Page_31">[31]</a></span> -membranes. (3) The microscopic experiments -so boasted of by Leiberkuhn, on -the erection of the intestinal villosities, -have been contradicted by those of Hunter -and Cruikshank, and, above all, by those -of Hewson. I can assert, that I have -never seen any thing of the kind on the -surface of the small intestines during the -absorption of chyle, and yet it appears to -be a thing that cannot vary in different -examinations. (4) It is true that these -intestinal villosities are everywhere accompanied -by a vascular web, which gives -them a colour very different from that of -the cutaneous papillæ; but the nonappearance -of the cutaneous web is occasioned -only by atmospherical pressure, by means -of the contraction that it produces in the -minute vessels: see, for instance, the -newly-born infant; its cutaneous surface -is as red as that of its mucous membranes, -and if the papillæ were a little more<span class="pagenum"><a name="Page_32" id="Page_32">[32]</a></span> -elongated the skin would exactly resemble -the internal surface of the intestines: -moreover, who does not know, that the -vascular web surrounding the papillæ is -rendered so apparent by fine injections as -entirely to change the colour of the -skin?</p> - -<p>30. That in the stomach this vascular -web exhales the gastric juice, and in the -intestines it is interlaced with the origin of -the absorbents, so that they embrace the -villosities, are facts that we must admit, -after the experiments and observations of -the anatomists, who in these times have -been engaged with the lymphatic system: -but that does not contradict the assertion, -that the bases of these villosities are -nervous, and perform the same functions -only on the mucous membrane as the papillæ -do on the cutaneous organ. This -view of them, by explaining their existence -as observed generally over all the mucous<span class="pagenum"><a name="Page_33" id="Page_33">[33]</a></span> -surfaces, appears to me much more conformable -to the plan of nature than to -suppose that they perform, in their different -parts, diverse and frequently opposite -functions.</p> - -<p>31. However, it is difficult to decide the -question by ocular observation; the tenuity -of these prolongations conceals their -structure even from our microscopic instruments, -a kind of agents by which -physiology and anatomy do not appear to -me in other respects ever to have obtained -great assistance, because when parts are -so viewed each person sees in his own -way, and is impressed accordingly. It is -therefore the observing of the vital functions -that should above all guide us. -Now by judging of the villosities in this -way it appears evident, that they have the -nature which I have attributed to them. -The following experiment will serve to -demonstrate the influence of the corps<span class="pagenum"><a name="Page_34" id="Page_34">[34]</a></span> -papillaire upon the cutaneous sensibility: -it succeeds also with mucous membranes. -If we remove any part of the epidermis, -and irritate the corps papillaire with a -pointed instrument, the animal writhes, -cries, and gives signs of acute pain. If -afterwards the cutis be pierced, and with -the instrument the internal surface of the -chorion be irritated, the animal will not -appear to suffer pain, unless by accident -some nervous filaments should be touched. -Thence it follows very evidently, that the -sensibility of the skin resides in its external -surface, that the nerves pass through -the chorion without being interwoven with -its texture, and that their diffusion only -takes place on the corps papillaire. It is -the same in mucous surfaces.</p> - -<p>32. The length and form of the villosities -vary in the different mucous surfaces. -Their appearance is not the same in the -stomach, the intestines, the bladder, the<span class="pagenum"><a name="Page_35" id="Page_35">[35]</a></span> -gall bladder, on the glans, &c.; which -variation exactly coincides with the sensibility -peculiar to each organ, a sensibility -proved by numerous observations since -Bordeu, who was the first to direct the -attention of physiologists to the particular -modifications that this property undergoes -in the different parts.</p> - -<p>33. Like the skin, the mucous membranes -have their chorion: it is thick on -the palate, gums, and pituitary membrane, -delicate in the stomach and intestines, not -very distinct in the bladder, gall bladder, -and excretory ducts. It appears to be -formed of condensed cellular strata, -strongly united, as in the skin. Maceration -develops this texture in a very sensible -manner. There is nevertheless this -difference, that in dropsy the cutaneous -chorion rises and resolves itself into distinct -cellules, that become filled with -water, whilst no such change takes place<span class="pagenum"><a name="Page_36" id="Page_36">[36]</a></span> -in the mucous chorion under similar circumstances. -Does this difference in the -morbid state suppose a dissimilarity of -structure? Certainly not; for the synovial -membrane is evidently of the same -nature as the serous membranes; and nevertheless -it does not participate in the -hydropic diathesis which often affects them -universally. It would be curious to expose -mucous membranes to the action of tan, -to see if they would present the same -phenomena as the skin.</p> - - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_37" id="Page_37">[37]</a></span></p> -<p class="p4" /> - -<h2><a name="SECTION_IV" id="SECTION_IV"></a><a href="#CONTENTS">SECTION IV.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small">OF THE GLANDS OF MUCOUS MEMBRANES.</span></h2> - - -<p>34. Besides the three strata, which -we have just mentioned, the mucous -membranes present in their structure a -great number of glands and blood vessels. -The mucous glands exist in all membranes -which bear that appellation: they are -situate under their chorion, and even in -its substance: they continually discharge, -through imperceptible orifices, a mucilaginous -fluid, which lubricates their free -surface, and defends it from the impression -of the bodies with which it is in -contact, at the same time that it facilitates -the passage of those substances.</p> - -<p><span class="pagenum"><a name="Page_38" id="Page_38">[38]</a></span></p> - -<p>35. These glands, which are very apparent -in the bronchi, palate, œsophagus, and intestines, -where they take the name of the -anatomists who have particularly described -them, are less obvious in the bladder, the -gall bladder, uterus, vesiculæ seminales, -&c.; but the mucus which moistens the -membranes unequivocally demonstrates -their existence. In fact, since this fluid -is nearly of the same nature on all the -mucous surfaces, and, in those where the -glands are apparent, is evidently furnished -by them, it must be secreted in the same -manner in those where they are less evident. -The identity of secreted fluids, certainly, -supposes the identity of the secreting -organs. It should seem, that in situations -where these glands escape our observation, -nature makes up for their tenuity by increasing -their number. In the lower -animals, particularly in the intestines, -they form by their number a kind<span class="pagenum"><a name="Page_39" id="Page_39">[39]</a></span> -of new layer, in addition to those we -have described. The same may be observed -in the palate, velum, &c. in -man.</p> - -<p>36. There is therefore this great difference -between mucous and serous membranes; -that the fluid which lubricates -the former is furnished by secretion, whilst -that which moistens the latter is produced -by exhalation. We know but little of the -composition of mucous fluids, because in -the natural state it is difficult to collect -them, and in the morbid state, where their -quantity increases, as for instance in catarrhs, -their composition probably undergoes -some alteration: but their functions -in the animal economy are well ascertained.</p> - -<p>37. The first of these functions is to defend -the mucous membranes from the impressions -of the bodies with which they -are in contact, and which, as we have ob<span class="pagenum"><a name="Page_40" id="Page_40">[40]</a></span>served, -are all heterogeneous to the animal. -Here, without doubt, we see the -reason why the mucous fluids are more -abundant in the cavities where these -bodies remain for some time, as in the -bladder, at the extremity of the rectum, -&c., than in those organs through which -they merely pass, as in the ureters, and -in general in all the excretory ducts. -Observe again, why, when the impression -of these bodies might be hurtful, -these fluids are poured out upon their -surfaces in a much greater quantity. The -sound which is introduced into the urethra, -and is allowed to remain there; -the instrument that is left in the vagina -to secure a polypus; that which, with -a similar intention, remains some time -in the nasal fossæ; the canula, fixed -in the lacrymal sac, to remove the obstruction; -and the tube that is introduced -into the œsophagus, when deglutition is<span class="pagenum"><a name="Page_41" id="Page_41">[41]</a></span> -interrupted, always determine a more -plentiful secretion upon the corresponding -mucous surface. This is one of the principal -causes why it is so difficult to retain -elastic tubes in the trachea; the abundance -of mucous fluid, which is then separated, -chokes up the apertures of the instrument, -and renders its frequent removal -necessary, and may even threaten the patient -with suffocation, as Desault has himself -observed, although he has nevertheless -many times succeeded with that operation.</p> - -<p>38. It therefore appears, that every -acute excitement of mucous surfaces determines, -in the corresponding glands, a -remarkable augmentation of action. But -how can this excitement, which does not -take place immediately upon the glands, -have so great an influence over them? -For, as we have said, these glands are -always subjacent to the membrane, and<span class="pagenum"><a name="Page_42" id="Page_42">[42]</a></span> -are consequently separated by it from the -irritating bodies. It appears that the -above fact belongs to a general modification -of the glandular sensibility, which -is susceptible of being put into action by -every irritation upon the extremities of -the excretory ducts, which will be proved -by the following considerations: (1) The -presence of food in the mouth produces -a more abundant flow of saliva. (2) The -catheter fixed in the bladder, and irritating -the ureters, or their vicinity, increases -the flow of urine. (3) The introduction -of a bougie, but half way up -the urethra, will often be sufficient to -occasion the bladder to contract with a -power equal to force the urine through -the passage, and so to overcome an obstruction -in the canal. (4) The irritation -of the glans, and of the extremity of the -urethra, <span lang="la" xml:lang="la">sub coitu</span>, determines the contraction -of the vesiculæ seminales, and<span class="pagenum"><a name="Page_43" id="Page_43">[43]</a></span> -augments the secretory action of the -testes. (5) The action of an irritating -fluid on the tunica conjunctiva occasions -an abundant flow of tears. (6) In making -experiments upon the state of the abdominal -viscera during digestion, and under -the influence of hunger, I have observed, -that whilst the food is only in the stomach -there is very little flow of bile; but -it increases when the aliment passes -into the duodenum, so that then there -is a considerable quantity in the intestines. -During hunger the gall bladder -is distended, and but little bile flows into -the intestines. At the end of digestion, -and even when that process is half finished, -the gall bladder contains but half of its -full quantity; yet it might be expected -to empty itself more easily during abstinence, -for then the bile it contains is of -a deep green colour, very bitter, very -acrid, and likely to irritate the organ<span class="pagenum"><a name="Page_44" id="Page_44">[44]</a></span> -which encloses it. On the contrary, during, -or immediately after digestion, it -is more clear, mild, and less irritating; -there must, therefore, be, during digestion, -another stimulus: now this stimulus -is the aliment passing over the mouth of -the ductus communis choledochus<a name="FNanchor_A_1" id="FNanchor_A_1"></a><a href="#Footnote_A_1" class="fnanchor">[A]</a>.</p> -<p><span class="pagenum"><a name="Page_45" id="Page_45">[45]</a></span></p> -<p>39. Let us conclude, from these numerous -considerations, that one of the principal<span class="pagenum"><a name="Page_46" id="Page_46">[46]</a></span> -means that nature employs to augment -the action of the glands, and to excite<span class="pagenum"><a name="Page_47" id="Page_47">[47]</a></span> -that of their excretory ducts, is irritation -upon the extremities of these ducts. We -must refer to that cause the abundant -secretion and excretion of mucous fluids -in the cases above stated. It is also to -this susceptibility of the mucous glands, -to be excited by irritation at the extremities -of their excretory ducts, that we -must attribute the artificial catarrhs which -are occasioned by the respiration of chlorine -gas; the flow of mucus which attends -a polypus, any tumour in the vagina, -stone in the bladder, &c. The frequent -occurrence of leuchorrhea in women -who use coition immoderately, the abun<span class="pagenum"><a name="Page_48" id="Page_48">[48]</a></span>dant -flow of mucus from the noses of -those persons who take snuff, in all these -cases there is evidently an irritation of the -mouths of the mucous ducts.</p> - -<p>40. The mucous membranes, by the -continual secretion of which they are the -seat, perform a principal part in the animal -economy. They are to be regarded -as one of the grand emunctories, by which -the residue of the nutriment constantly -escapes from the body; and consequently -as one of the principal agents of that -habitual decomposition which carries away -from living bodies the particles which -for some time formed part of the solids, -but have at length become heterogeneous -to them.</p> - -<p>41. Remark the fact, that none of the -mucous fluids enter into the circulation, -but are thrown out externally; that of -the bladder, ureters, and urethra, with -the urine; that of the vesiculæ seminales<span class="pagenum"><a name="Page_49" id="Page_49">[49]</a></span> -and of the vassa defferentia with the semen; -that of the nostrils by the action -of blowing the nose; that of the mouth -partly by evaporation, and partly by the -anus with the excrements; that of the -bronchi by the pulmonary exhalation, which -is effected principally by the solution of -this mucous fluid in the air of respiration; -those of the œsophagus, of the stomach, -of the intestines, of the gall bladder, -&c., with the excrements of which they -frequently form, in the ordinary state, a -part nearly equal to the residue of the -aliment; and they even compose almost -the whole of the matter voided in certain -dysenteries and fevers, where the quantity -is evidently disproportionate to the food -that has been taken. Let us observe on -this subject, that in the analysis of the -fluids, in contact with the membranes of -which we speak, as the urine, bile, gastric -juice, &c., there are always some errors,<span class="pagenum"><a name="Page_50" id="Page_50">[50]</a></span> -because it is very difficult, impossible even, -to separate them from the mucous fluids.</p> - -<p>42. If we call to mind what has been -said above, upon the extent of the two -general mucous surfaces, that they are -equal and even superior to the extent of -the cutaneous organ; if we afterwards -contemplate these two grand surfaces, -constantly throwing off the mucous -fluids, we shall see of what importance -this evacuation must be in the economy, -and of what derangements its lesion may -become the source. It is doubtless to this -law of nature, which ordains that every -mucous fluid shall be rejected externally, -that in the fœtus we must attribute the -presence of the unctuous fluid, of which -the gall bladder is full, and of the meconium -choking up the intestines, &c., -kinds of fluids which appear to be only -a collection of mucous juices, which, as -they cannot be evacuated, remain, until<span class="pagenum"><a name="Page_51" id="Page_51">[51]</a></span> -birth, upon the organs where they have -been secreted.</p> - -<p>43. It is not the mucous fluids only -that are rejected externally; almost all the -fluids, separated from the mass of blood -by the means of secretion, have the same -destiny: this is evident in the most considerable -part of the bile. It is very probable, -also, that the saliva, the pancreatic -juice, and the tears, are discharged with -the fæces, and that it is their want of -colour alone that prevents them from -being distinguished like the bile. I do -not know even if, in reflecting on a crowd -of phenomena, one would not be tempted to -establish, as a general principle, that no -fluid, separated by secretion, returns into -the circulation; that this destination belongs -only to fluids separated by exhalation, -as those of the serous cavities, of -the articulations, of the medullary organ, -&c.; that all the fluids are thus excre<span class="pagenum"><a name="Page_52" id="Page_52">[52]</a></span>mental -or recremental, and that there is -no recremental excrement, as the common -division points out<a name="FNanchor_B_2" id="FNanchor_B_2"></a><a href="#Footnote_B_2" class="fnanchor">[B]</a>.</p> - -<p>44. What is certain, at least, is, (1) -that I have never been able to effect the -absorption of bile or saliva by the lymphatics. -When I have injected them into -the cellular tissue of an animal they have -always produced inflammation and suppuration. -(2) We know that the urine, when -infiltrated, does not become absorbed, and -that it strikes with death every part that it -touches; whilst the infiltrations of lymph, -or of blood, are readily absorbed. (3)<span class="pagenum"><a name="Page_53" id="Page_53">[53]</a></span> -There is an essential difference between -the blood and the secreted fluids as concerns -their decomposition, whilst exhaled -fluids and serum, &c., are in that respect -very similar.</p> - - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_54" id="Page_54">[54]</a></span></p> -<p class="p4" /> - - <div class="chapter"></div> - -<h2><a name="SECTION_V" id="SECTION_V"></a><a href="#CONTENTS">SECTION V.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small">OF THE VASCULAR SYSTEM OF MUCOUS -MEMBRANES.</span></h2> - - -<p>45. The mucous membranes receive a -great number of vessels: the remarkable -redness which distinguishes them would -be sufficient to prove it to us, if it could -not be demonstrated by injections. This -redness is not everywhere uniform; it is -less in the bladder, large intestines, and -frontal sinuses; very marked in <ins class="corr" title="Transcriber's Note—Original text: 'the mach, small'">the -stomach, small</ins> intestines, and vagina, &c. -It is produced by a web of very numerous -vessels, whose supplying branches, after -having passed through the chorion, finish<span class="pagenum"><a name="Page_55" id="Page_55">[55]</a></span> -on its surface by an infinite division, embracing -the corps papillaire, and is covered -only by the epidermis.</p> - -<p>46. It is the superficial position of these -vessels that frequently exposes them to -hæmorrhages, as we remark principally -in the nose, and as is seen in hæmoptysis, -hæmatemæsis, hæmaturia, in certain -dysenteries, where the blood escapes from -the parieties of the intestines, in uterine -hæmorrhages, &c.; so that those spontaneous -hæmorrhages, which are independent -of any external violence applied -to the open vessels, appear to be special -affections of the mucous membranes; they -are seldom observed but in these organs, -and they form at least one of the grand -characteristics which distinguishes them -from all the other membranes.</p> - -<p>47. It is also the superficial situation -of the vascular system of mucous membranes -that renders their visible portions,<span class="pagenum"><a name="Page_56" id="Page_56">[56]</a></span> -as on the lips, the glans, &c.; serviceable -in showing us the state of the circulation. -Thus, in various kinds of asphyxia, -in submersion, strangulation, &c., -these parts present a remarkable lividity; -the effect of the difficulty that the venous -blood finds in passing through the lungs, -and of its reflux towards the surfaces -where the venous system arises from that -of the arteries.</p> - -<p>48. I have already observed in the -fœtus, and newly born infant, that the -vascular system is as apparent in the cutaneous -organ as in the mucous membranes; -that the redness is there the -same; it is even in that part more marked -in the earlier periods of conception; but -soon after birth all the redness of the -skin seems to concentrate itself upon the -mucous membranes, which before, being -inactive, had no need of so considerable -a circulation, but which, becoming all at<span class="pagenum"><a name="Page_57" id="Page_57">[57]</a></span> -once the principal seat of the phenomena -of digestion, of the excretion of the bile, -of the urine, of the saliva, &c., demand -a larger quantity of blood. The long -continued exposure of mucous membranes -to the air frequently occasions them to -lose their characteristic redness, and they -then assume the colour of the skin (as -M. Sabattier has well observed in treating -on prolapses of the uterus and vagina). -By this circumstance some have been deceived -in believing such instances to be -cases of Hermaphrodism.</p> - -<p>49. An important question in the history -of the vascular system of the mucous -membranes presents itself, which is, does -this system admit more or less blood, -according to its various circumstances? -As the organs within which this sort of -<ins class="corr" title="Transcriber's Note—Original text: 'membranes is spread'">membrane is spread</ins> are nearly all of -them susceptible of contraction and dilatation, -as is observable in the stomach,<span class="pagenum"><a name="Page_58" id="Page_58">[58]</a></span> -intestines, bladder, &c., it has been believed, -that during their dilatation the -vessels, being more spread out, received -more blood, and that during their contraction, -on the contrary, being folded on -themselves, and as it were strangulated, -they admitted but a small portion of this -fluid, which then flows back into the -adjacent organs. M. Chaussier has applied -these principles to the stomach, the -circulation of which he has considered as -being alternately the inverse of that of the -omentum, which receives, during the vacuity -of that organ, the blood which it, -being in a state of contraction, cannot -admit. Since M. Lieutaud, an analogous -use has been attributed to the spleen. -Observe what I have ascertained on this -subject from the inspection of animals -opened during abstinence, and in the -various periods of digestion.</p> - -<p>50. (1) Whilst the stomach is in a<span class="pagenum"><a name="Page_59" id="Page_59">[59]</a></span> -state of repletion its vessels are more apparent -on its exterior surface than during -its vacuity; its mucous surface at this -time has no higher degree of redness, but -it has sometimes appeared to me to be -less red than when the viscus was empty. -(2) The omentum, being less extended -during the plenitude of the stomach, presents -nearly the same number of apparent -vessels, equal in length, but more folded -upon themselves than during the vacuity -of that organ<a name="FNanchor_C_3" id="FNanchor_C_3"></a><a href="#Footnote_C_3" class="fnanchor">[C]</a>. If they are then less -<span class="pagenum"><a name="Page_60" id="Page_60">[60]</a></span> -loaded with blood the difference is scarcely -perceptible. I would here observe, that -great care is requisite in opening the -animal, or the blood will fall upon the -omentum, and prevent us from ascertaining -its real state. (3) I am confident that -there is no such constant relation between -the volume of the spleen and the stomach -in its different states of vacuity or plenitude; -and if that organ increases and -diminishes under various circumstances, it -is not always in the inverse ratio of the -state of the stomach. Like Lieutaud, I -at first made experiments on dogs, in -order to satisfy myself respecting the facts -just stated; but the inequality in the size -and age of those which were brought to<span class="pagenum"><a name="Page_61" id="Page_61">[61]</a></span> -me leading me to fear that I might not be -able to compare their spleens correctly, I -repeated them on Guinea pigs, whose size -and condition corresponded, and examined, -at the same time, some whilst the -stomach was empty, and others whilst it -was full. I have almost always found the -volume of the spleen nearly equal, or at -least the difference has not been very perceptible. -Nevertheless, in other experiments -I have seen the spleen, under various -circumstances, to show variations -in its volume, but more particularly in -weight; and this was the same during -digestion as after that process was finished. -From what has been said it appears, that -if, whilst the stomach is empty, there is a -reflux of blood to the omentum and spleen, -it is less than has been commonly asserted. -Moreover, during this state of vacuity, -the numerous folds of the mucous membrane -of this viscus leaving it, as we have<span class="pagenum"><a name="Page_62" id="Page_62">[62]</a></span> -before said, almost as much extent of -surface, and consequently of vessels, as -during its plenitude, the blood must circulate -there nearly as freely as when the -viscus is in a contrary state; it has therefore -no real obstacles; the only impediment -is in consequence of the tortuous -direction the vessels are then thrown into. -Now this obstacle is easily surmounted, -since the vessels suffer no constriction or -diminution of calibre by the contraction -of the stomach.</p> - -<p>51. As respects the other hollow organs, -it is difficult to examine the circulation of -their adjacent viscera during their plenitude -or vacuity; for their vessels are not -superficial, as in the omentum, or insulated, -as in the spleen; therefore, to decide -this question concerning them, we -can only observe the state of the mucous -membranes upon their internal surface. -Now they have always appeared to me as<span class="pagenum"><a name="Page_63" id="Page_63">[63]</a></span> -red during the contraction as during the -dilatation of the organs. Finally, I give -this only as a fact, without pretending to -draw any inference from it opposed to the -common opinion. It is, in fact, possible, -that though the quantity of blood be always -nearly the same, the rapidity of the -circulation may increase; and consequently, -in a given time, more of this fluid -will be sent there during the plenitude of -the viscera. This appears to be necessary -for the secretion of the mucous fluids, -which are then more abundant.</p> - - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_64" id="Page_64">[64]</a></span></p> -<p class="p4" /> - -<h2><a name="SECTION_VI" id="SECTION_VI"></a><a href="#CONTENTS">SECTION VI.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small">OF THE VARIATIONS IN THE ORGANIZATION -OF MUCOUS MEMBRANES IN DIFFERENT -REGIONS.</span></h2> - - -<p>52. The assemblage of the epidermis, -corps papillaire, chorion, glands, and -vessels, constitutes in the mucous membranes -their intimate organization, which -presents very considerable variations in -the different regions in which they are -examined. I shall point out only the -principal of them; for in no different parts -do these membranes present the same appearance, -and in order to describe all their -differences they should all be examined.</p> - -<p><span class="pagenum"><a name="Page_65" id="Page_65">[65]</a></span></p> - -<p>53. One of these variations is that -which the aspect of mucous membranes -presents at their origin, when compared -with their appearance in the more remote -parts of the organs. Compare, for instance, -the surface of the glans, the inner -surface of the lips, the orifice of the urethra, -&c., with any portion of the inner -surfaces of the stomach, intestines, &c. -In the first the corps papillaire will be -seen slightly marked, and offering no villous -character, the epidermis thick, very -distinct, and easily separated, the chorion -very evident, the vessels rather less superficial, -the mucous glands numerous and -very large, more especially in the mouth; -in the other characters almost opposite -will be observed; we should say, that the -mucous membranes have at their origin a -structure of a middle kind between the -skin and their deeper portions.</p> - -<p>54. Another variation of structure, not<span class="pagenum"><a name="Page_66" id="Page_66">[66]</a></span> -less striking, is that which is met with in -that portion of mucous surface which lines -the sinuses. Here it has more redness, -and an extreme tenuity; the three layers -cannot be distinguished; and although -there is a considerable secretion of mucous -fluids, there are no perceptible mucous -glands. Such are the characters of those -portions of the pituitary membrane, which -are considered as adapted to augment the -sensation of smell, but which do not perform -that function in the manner generally understood. -In fact, the instant when an -odour enters the nose, having the air for -its vehicle, it cannot at once pass into the -sinuses, because the orifices by which -these cavities communicate with the nose -are very small; but it enters gradually, -impregnates all the air which they contain, -and not being able to escape readily, for -the same reason that rendered its entrance -difficult, the sensation is prolonged, which<span class="pagenum"><a name="Page_67" id="Page_67">[67]</a></span> -on the general pituitary membrane is soon -dissipated by the action of the fresh air. -Thus therefore the pituitary membrane is -destined to receive the impressions of -odours, and its extensions into the cavities -of the sinuses to retain them.</p> - -<p>55. With regard to the particular structure -of that portion of mucous membrane -which lines the sinuses I remark, that it -is absolutely the same as of that which -is spread over the surface of the internal -ear, with the exception of a still more -delicate tissue. All anatomists call this -membrane the periosteum of the bony -covering of the internal ear. The following -considerations prove that it is not a -fibrous membrane, analogous to that -which covers the bones, but a mucous -layer, like that of the sinuses. (1) It is -evidently seen to be a continuation of the -pituitary membrane by the medium of the -Eustachian tube. (2) It is found to be<span class="pagenum"><a name="Page_68" id="Page_68">[68]</a></span> -habitually moist with a mucous fluid, -which is discharged through that tube, a -property foreign to fibrous membranes, -both of whose surfaces are always attached -to some parts of the animal structure. -(3) No fibre can be distinguished -in it. (4) Its spongy appearance, though -whitish, its softness, the readiness with -which it gives way to the least agent directed -against it, with a view to tear it, -form a character not to be found in any -part of the periosteum.</p> - -<p>56. I pass over the other variations of -structure in mucous membranes in their -different regions; in all they have real -differences. I observe only, (1) That -these variations distinguish them from -serous membranes, whose aspect is everywhere -the same, as may be seen by comparing -the pericardium with the peritoneum, -&c. (2) The sensibility of mucous -membranes varies in a very peculiar man<span class="pagenum"><a name="Page_69" id="Page_69">[69]</a></span>ner -in their different portions: thus an emetic -irritates the stomach, but not the conjunctiva; -the pituitary membrane perceives -only odours; the mucous surface of the -tongue flavours, &c. On the contrary, -the contact of all kinds of bodies with -the naked serous membranes produces -phenomena exactly analogous.</p> - - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_70" id="Page_70">[70]</a></span></p> -<p class="p4" /> - -<h2><a name="SECTION_VII" id="SECTION_VII"></a><a href="#CONTENTS">SECTION VII.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small">OF THE VITAL POWERS OF THE MUCOUS -MEMBRANES.</span></h2> - - -<p>57. The sensibility of mucous membranes -is one of the principal characteristics -that distinguishes them from other -analogous organs. This power, which -belongs to organic bodies, is variable in -every part, prompt to develop itself in -some parts, under the influence of the least -excitement, roused with difficulty in -others, present in every part, liable to -proceed by means of inflammation from -the most obscure state to the last degree -of intensity—this power is here remark<span class="pagenum"><a name="Page_71" id="Page_71">[71]</a></span>able -for features very analogous to those -which it presents in the cutaneous surface -(to which, as we have stated, the mucous -surface has great traits of resemblance) -as respects its structure. It is to -this analogy of sensibility that we must -refer a crowd of phenomena, which are -alternately exhibited in an inverse order -upon both surfaces. I shall now point -out some of these phenomena in succession.</p> - -<p>58. (1) When the temperature of the surrounding -air deadens the sensibility of the -cutaneous organ, by contracting its tissue, -the sensibility of the mucous surface receives -a remarkable increase of energy. -Observe why in winter, and in cold climates, -where the functions of the skin -are singularly limited, all those of the -mucous membranes are in proportion augmented; -thence arises a more evident -pulmonary exhalation, the internal secre<span class="pagenum"><a name="Page_72" id="Page_72">[72]</a></span>tions -are more abundant, digestion is more -active and more ready to operate, consequently -the appetite is the more easily excited. -(2) When, on the contrary, the -heat of the climate, or of the season, &c. -relaxes and opens the cutaneous surface, -we should say, that the mucous surface is -in proportion constricted: during summer, -in the south, &c. there is a diminution in -the internal secretions, the urine for instance; -a tardiness in the digestive phenomena -by a default in the actions of the -stomach and intestines, and the appetite -is slow in returning. (3) The sudden -suppression of the functions of the cutaneous -organ often determines a morbid -increase of action in those of the mucous -membrane. Cold air, which checks the -perspiration, frequently produces colds -and catarrhs, affections which are marked -by the sensibility and increased action of -the mucous glands. (4) In various affec<span class="pagenum"><a name="Page_73" id="Page_73">[73]</a></span>tions -of the mucous membranes, baths, -which relax and determine to the skin, -produce beneficial effects.</p> - -<p>59. The foregoing considerations evidently -establish the influence, which the -vital powers of the skin have over those -of the mucous membranes. Others, -not less important, demonstrate the reciprocal -dependence in which the skin -is found with the same membranes, -as respects their vital powers. (1) During -digestion, when the mucous fluids -are poured out in abundance into the -stomach and intestines, when, consequently, -the mucous membranes of the -alimentary canal are in high action, the -fluid of insensible perspiration is evidently -diminished, according to the observation -of Santorius: it is very small in quantity -three hours after a meal, so that the action -of the cutaneous organ is visibly less -energetic. (2) During sleep, when all<span class="pagenum"><a name="Page_74" id="Page_74">[74]</a></span> -the internal functions become more -marked and are in full action, at which -time the sensibility of the mucous membranes -is consequently highly excited, the -skin appears to be seized by a manifest -debility—a debility, which is evinced by -the cold which it experiences when the -animal reposes at night uncovered, and -by its want of susceptibility of various -impressions.</p> - -<p>60. The sensibility of the mucous membranes, -like that of the cutaneous organ, -is essentially submissive to the immense -influence of habit, which, tending incessantly -to blunt the acuteness of the sensations -of which they are the seat, reduces -the pain and the pleasure that we -receive through them equally to indifference, -which is, as some say, the middle -state.</p> - -<p>61. I say, in the first place, that habit -reduces the painful sensations, which take<span class="pagenum"><a name="Page_75" id="Page_75">[75]</a></span> -place on mucous membranes, to indifference. -The presence of the catheter, -which is passed up the urethra for the -first time, is cruel the first day, painful -the second, inconvenient the third, scarcely -felt the fourth; pessaries introduced into -the vagina, bougies into the rectum, tents -in the nasal fossæ, the canula in the -nasal canal, produce, in different degrees, -the same phenomena. It is upon this -remark that is founded the possibility -of introducing instruments into the trachea -to aid respiration, and into the œsophagus -to afford artificial deglutition. -This law of habit may even transform -a painful into a pleasant impression; of -this fact the use of snuff, tobacco, and -various kinds of food, furnish us with -remarkable examples.</p> - -<p>62. In the second place I observe, -that habit produces indifference to those -sensations on the mucous membranes<span class="pagenum"><a name="Page_76" id="Page_76">[76]</a></span> -which were at first agreeable. The perfumer -placed in a fragrant atmosphere, -and the cook, whose palate is constantly affected -by delicious flavours, do not experience, -in their professions, the exquisite -pleasures that they prepare for -others. Habit may even change pleasant -sensations to painful ones, as in the preceding -paragraph we saw it changed painful -to pleasing sensations. I observe, further, -that this remarkable influence of -habit is exercised only over sensations -produced by simple contact, and not over -those produced by real lesion of the mucous -membranes: thus it does not ameliorate -the pain produced by stone in the -bladder, nor that which attends polypus -in the uterus.</p> - -<p>63. It is to this power of habit over -the vital energies of the mucous membranes -that we must, in part, refer the -gradual diminution of their functions which<span class="pagenum"><a name="Page_77" id="Page_77">[77]</a></span> -accompanies advancing age. All is susceptibility -in the infant: in old age all -is dull. In the one the very active sensibility -of the alimentary, biliary, urinary, -and salivary mucous surfaces, is that -which principally produces that rapidity -with which the digestive and secretory phenomena -succeed each other. In the other -this sensibility, weakened by the habit -of contact, does not so closely connect -the same phenomena.</p> - -<p>64. Does not the following remarkable -modification of the sensibility of the mucous -surfaces depend upon the same -cause, <em>viz.</em> that at their origin, as on the -pituitary membrane, the glans, the anus, -&c., they give us the sensations of bodies -with which they are in contact, and that -they do not produce this sensation in the -deeply seated organs which they line, as -the intestines, &c.? In the interior of -these organs this contact is always uni<span class="pagenum"><a name="Page_78" id="Page_78">[78]</a></span>form; -the bladder is in contact with the -urine only, the gall bladder with the bile, -the stomach with the aliments masticated -and reduced to an homogeneous, pulpy -paste, whatever may be their diversity. -This uniformity of sensation prevents perception, -because, in order to perceive, -we must compare, and here two terms -of comparison are wanting. Thus the -fœtus has no sensation of the liquor amnii: -the air is also very irritating at first -to the new-born infant, but at length it -is not felt. On the contrary, at the origins -of mucous membranes exciting agents -vary every instant: the mind can, therefore, -perceive their presence, because it -is able to establish relations between their -various modes of action. What I say is -so true, that if in the interior of the -organs the mucous membranes be in contact -with a foreign body differing from -that which is habitual to them, they<span class="pagenum"><a name="Page_79" id="Page_79">[79]</a></span> -transmit the sensation of it to the mind; -instruments introduced into bladder or -stomach are examples of it. Fresh air, -which in very hot weather is suddenly -introduced into the trachea, causes an -agreeable sensation over the surface of -the bronchi; but from habit we soon -become insensible to it, and the perception -ceases.</p> - -<p>65. It is very difficult to point out -with precision the character of the tonic -powers of mucous membranes, because, -being almost in every part united to a -muscular layer, we can hardly distinguish -what belongs to the tonicity of the one -from what depends upon the irritability of -the other; or otherwise, if the mucous -membranes be isolated, as in the nostrils, -yet their attachment renders the phenomena -of their tonic powers very obscure. -Nevertheless, the action of the excretory -ducts on their respective fluids, that of<span class="pagenum"><a name="Page_80" id="Page_80">[80]</a></span> -the gall bladder, and of the vesiculæ seminales, -which are destitute of muscular -attachments, and the spasmodic contraction -of the urethra, which sometimes takes -place when the sound is introduced, leave -no doubt of the energy of this tonic -power, doubtless similar in its various -modifications to that which is observed in -the cutaneous organ.</p> - - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_81" id="Page_81">[81]</a></span></p> -<p class="p4" /> - -<h2><a name="SECTION_VIII" id="SECTION_VIII"></a><a href="#CONTENTS">SECTION VIII.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small"><ins class="corr" title="Transcriber's Note—Original text: 'OF THE SYMPATHY'">OF THE SYMPATHIES</ins> OF MUCOUS MEMBRANES.</span></h2> - - -<p>66. I distribute the sympathies of -mucous membranes, like those of most -of the other organs, into three general -classes. In the first class are ranked the -sympathies in which irritation, on one part -of the mucous surface, produces a sensation -in a distant part. A stone in the -bladder occasions pain at the end of -glans; worms in the intestines excite an -itching at the nose. Whytt has seen a -painful affection induced over the whole -side of the head by a foreign body in the<span class="pagenum"><a name="Page_82" id="Page_82">[82]</a></span> -ear; an ulcer in the bladder produces a -pain in the superior parts of the thighs -every time that the patient passes his -urine.</p> - -<p>67. I refer to the second class those -sympathies in which the irritation of one -point on mucous surfaces produces irritability -in a different structure; thus, too -lively an impression on the pituitary membrane -occasions sneezing; the irritation -of the bronchi coughing; biliary concretions -produce spasmodic vomiting; stones -in the bladder occasion retraction of the -testicle towards the ring. In all these -cases there is contraction of the muscles -produced by the irritation of the mucous -surface, distant from the place in which -that contraction occurs.</p> - -<p>68. The last class of the sympathies -of mucous membranes embraces those in -which the irritation of any part of their -extension determines elsewhere the exer<span class="pagenum"><a name="Page_83" id="Page_83">[83]</a></span>cise -of their tonicity. Here we must refer -to what we have said upon glandular -action being augmented by the irritation -of the extremities of the excretory ducts. -Thus it is evident, that the increase of -the tonic power of the parotid for the -secretion of the saliva, and of its excretory -duct in order to transmit it, when the -extremity of this duct is irritated by food, -sialogogue medicines, &c.,—it is evident, -I say, that this augmentation is a phenomenon -purely sympathetic. We may designate -each of these three classes by the -name of the vital power which they bring -into action, calling the first sympathy of -sensibility; the second, sympathy of irritability; -and the third, sympathy of tonicity.</p> - -<p>69. This manner of classing the sympathies -is entirely borrowed from the state -of the vital powers, of which they are but -irregular modifications, and only aberra<span class="pagenum"><a name="Page_84" id="Page_84">[84]</a></span>tions, -still unknown in their nature. Nevertheless -it is subject to very great inconveniences: -yet it appears to me to -be preferable to that of Whytt, who simply -follows the order of the regions; and -even to that of Barthy, who, more methodical, -examines them successively in -the organs connected by systems, in -those which are insulated, and in those -situated in symmetrical halves of the -body.</p> - - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_85" id="Page_85">[85]</a></span></p> -<p class="p4" /> - -<h2><a name="SECTION_IX" id="SECTION_IX"></a><a href="#CONTENTS">SECTION IX.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small">OF THE FUNCTIONS OF MUCOUS MEMBRANES.</span></h2> - - -<p>70. I have already examined many of -the functions of mucous membranes. I -have considered them (1) As one of the -grand emunctories of the animal economy. -(2) As performing the same functions with -respect to heterogeneous bodies, which -may be within our organs, as the skin -does with regard to the bodies with which -it may be in contact. (3) As facilitating -the passage of foreign bodies by means of -the mucous fluid by which they are lubricated. -It remains for me to examine three<span class="pagenum"><a name="Page_86" id="Page_86">[86]</a></span> -questions much agitated at this time. -(1) If the mucous membranes have any -influence over the redness of the blood. -(2) If they exhale. (3) If the absorbents -arise from them; and if absorption consequently -takes place there.</p> - -<p>71. The remarkable redness of these -membranes, the analogy of respiration, -during which the blood becomes changed -in colour through the mucous surface of -the bronchi, the well-known experiment -of a bladder filled with blood and placed -in oxygen gas, by which this fluid becomes -also changed in colour,—have led to the -belief, that the blood, being separated -from the atmospheric air merely by a very -<ins class="corr" title="Transcriber's Note—Original text: 'fine pelicle'">fine pellicle</ins> on certain mucous surfaces, as -the pituitary membrane, the palatine, the -glans, &c., would there also take a -brighter red colour, either by parting with -a portion of carbonic acid gas, or by combining -with the oxygen of the atmosphere,<span class="pagenum"><a name="Page_87" id="Page_87">[87]</a></span> -and that these membranes thus fulfilled -functions accessory to those of the lungs. -The experiments of Jurine upon the cutaneous -organ, experiments adopted by -many celebrated physicians, appear also to -favour the reality of that conjecture.</p> - -<p>72. Observe the experiment that I have -tried, in order to ascertain the validity of -that fact. Through a wound in the abdomen -I drew out a portion of intestine, -which I tied at one point. I then returned -it, keeping back a part, which I punctured, -and introduced into it sufficient -atmospheric air to distend all that portion -of the bowel between the ligature and the -orifice. I then confined the air by another -ligature, and reduced the whole. At the -end of an hour the animal was opened. -I compared the blood of the mesenteric -veins, which arise from that portion of -intestine distended by air, with the blood -of the other mesenteric veins arising from<span class="pagenum"><a name="Page_88" id="Page_88">[88]</a></span> -the remainder of the canal: no difference -of colour could be observed: the internal -surface of the inflated intestine did not -exhibit a brighter red. I expected to -obtain a more marked effect by repeating -the same experiment on another animal -with oxygen gas, but I did not perceive -any variation in the colour of the blood. -As on the mucous membranes, which are -ordinarily in contact with the air, this -fluid is constantly renewed, and is agitated -by a perpetual movement, I tried to produce -the same effect in the intestines; for -which purpose I made two openings into -the abdomen, through each of which I -drew a portion of the intestinal tube. I -opened these two portions, adapting to -one the tube of a bladder filled with oxygen -gas, and to the other that of an empty -bladder. I then pressed the full bladder -so as to make the oxygen gas pass into -the empty one through the intermediate<span class="pagenum"><a name="Page_89" id="Page_89">[89]</a></span> -portion of intestine which was in the abdomen, -so that the warmth there might -encourage the circulation. The oxygen -gas was in this manner sent many times -from one bladder to the other, making a -current through the intestine, which from -its contraction was more difficult than it -at first appeared to be. The abdomen -was then opened, but no difference was -found between the venous blood returning -from that portion of the intestine, and -that which flowed from the other parts of -the canal. The superficial situation of -the mesenteric veins, which are covered -by only a fine transparent lamina of peritoneum, -and their volume when the animal -is not fat, render these comparisons -very easy to be made.</p> - -<p>73. I think, that from what occurs in -the intestines we cannot infer what takes -place in the pituitary and palatine membranes, -&c.; because, although analogous,<span class="pagenum"><a name="Page_90" id="Page_90">[90]</a></span> -their organization may be different. In -these parts we cannot examine the venous -blood returning from them, as in the intestines: -but, (1) If we consider, that -in animals, which have for some time -respired oxygen gas, the mucous membrane -of the fauces does not exhibit any -increase of redness; (2) If we bear in -mind, that the lividity of different parts of -this membrane, <ins class="corr" title="Transcriber's Note—Original text: 'in those asphyxies'">in those asphyxias</ins> which -are produced by carbonic acid gas, is not -occasioned by the immediate contact of -this gas with the membranes, but by the reflux -towards the surface, of the venous blood -which cannot pass through the heart, as -occurs in submersion, as demonstrated by -Godwin, and as takes place in all those -cases in which the blood, previous to -death, has found difficulty in passing -through the lungs; (3) If we remark -lastly, that in these circumstances the -contact of the air, after death, does not<span class="pagenum"><a name="Page_91" id="Page_91">[91]</a></span> -alter the lividity that the venous blood -gives to the mucous membranes, although -the skin is then more permeable to every -kind of æriform fluid;—we shall see that -we must at least suspend our judgment, -respecting the colouring of the blood -through mucous membranes, until farther -observations shall have decided the question.</p> - -<p>74. Observe another experiment, which -may throw more light still upon the subject. -I have distended the peritoneal -cavity of different Guinea pigs with carbonic -acid gas, with hydrogen gas, with -oxygen gas, and with atmospheric air, to -see if I could obtain, through a serous -membrane, what I had not been able to -effect through a mucous surface. In -these experiments I have found no difference -in the colour of the blood of the -abdominal system: it was the same as in -fresh animals of the same kind, that I<span class="pagenum"><a name="Page_92" id="Page_92">[92]</a></span> -always used to compare with those on -which the experiments were made.</p> - -<p>75. I believe, nevertheless, that I have -observed many times, both in frogs and in -animals with warm and red blood, such -as cats and Guinea pigs, that the infiltration -of oxygen gas into the cellular tissue -gives, after a certain time, a brighter -colour to the blood than this fluid presents -in the artificial emphysemas which may be -produced by carbonic acid gas, hydrogen -gas, or by atmospheric air, in which circumstances -the blood differs very little in -colour from its natural shade. But in -other cases oxygen gas has had no influence -over the colour of the blood; so -that, notwithstanding the many experiments -that have been made on this point, -I cannot state any general result. It -appears, that the tonic powers of the cellular -tissue, and of the coats of the -vessels which ramify in it, receive a very<span class="pagenum"><a name="Page_93" id="Page_93">[93]</a></span> -varied influence from the contact of the -gases, and that, according to the nature -of that influence, the fibres contracting -and becoming more or less firm render -these parts more or less permeable, both -to the æriform fluids, which have a tendency -to escape from the blood to unite -with that of the emphysema, and to this -last fluid, if it tends to combine with the -blood. This will doubtless explain the -variations that I have observed.</p> - -<p>76. Do the mucous surfaces exhale? -The analogy of the skin would seem to -lead to the belief of it; for it appears well -proved, that the perspiration is not a -transudation by the inorganic pores of the -cutaneous surface, but a true transmission -by vessels of a particular nature, and continuous -with the arterial system.</p> - -<p>77. It appears, at first, that the pulmonary -perspiration which takes place on -the surface of the bronchi, which has<span class="pagenum"><a name="Page_94" id="Page_94">[94]</a></span> -such connection with that of the skin, -which increases or diminishes according -to the decrease or augmentation of the -other, and of which the composition is -apparently of the same nature—it appears, -I say, that the pulmonary perspiration -is produced, at least in part, by -the system of exhalent vessels; and that -if the combination of the oxygen of the -air concurs with the hydrogen of the -blood to produce it, during the act of respiration, -it is but in a very small quantity, -and for that portion only which is -purely aqueous. It is necessary to observe -further on this subject, that the dissolution -of the mucous fluid, which lubricates -the bronchi, in the air that is constantly -inspired and expired, furnishes a considerable -portion of that vapour which rises -from the lungs, and which is insensible in -summer, but very apparent in winter.</p> - -<p>78. The intestinal juice, that Haller<span class="pagenum"><a name="Page_95" id="Page_95">[95]</a></span> -has particularly considered, but which -appears to be less in quantity than he had -estimated, the gastric juice, and that of -the œsophagus, are very probably disposed -of by way of exhalation on their respective -mucous surfaces; but in general it is -very difficult to distinguish with precision, -in these organs, what belongs to the -exhalent system from what is furnished -by the system of mucous glands, which, as -we have said, are everywhere subjacent to -them. Thus we constantly see the mucous -fluids of the œsophagus, stomach, and -intestines, mix themselves with the other -fluids of these parts.</p> - -<p>79. That mucous membranes absorb is -evidently proved by the absorption of the -chyle upon the intestinal surfaces, of venereal -virus upon the glans and urethra, -of variolous poison which is sometimes -rubbed upon the gums, of the serous -portions of the bile, of the urine, and of<span class="pagenum"><a name="Page_96" id="Page_96">[96]</a></span> -the semen, when they remain in their -respective reservoirs. When, from paralysis -of the fleshy fibres which terminate -the rectum, the fæces accumulate at the -extremity of that intestine (a very common -case in aged persons, and of which -Desault has cited many instances), these -accumulations frequently become hard, -probably from the absorption of their -juices, which are obstructed there. We -have many cases in which the urine has -been almost entirely absorbed by the mucous -surface of the bladder, when there -has been absolute obstruction in the urethra. -Whatever may be the mode of this -absorption, it appears that it is not performed -in a constant, uninterrupted manner, -like that of the serous membranes, -in which the exhalent and absorbent systems -are in a continual alternate action; -but that it occurs only under certain circumstances, -of which perhaps the greatest<span class="pagenum"><a name="Page_97" id="Page_97">[97]</a></span> -part are not in the natural order of the -functions. Finally, we have yet fewer -data respecting the mode of mucous absorption -than on that of cutaneous absorption: -we confess it is very little understood, -and many even question its existence.</p> - - -<hr class="chap" /> -<p><span class="pagenum"><a name="Page_98" id="Page_98">[98]</a></span></p> -<p class="p4" /> - -<h2><a name="SECTION_X" id="SECTION_X"></a><a href="#CONTENTS">SECTION X.</a><br /> -<br /><br /> -<img src="images/sep.jpg" width="100" alt="" /><br /> -<br /> -<span class="small">REMARKS ON THE AFFECTIONS OF MUCOUS MEMBRANES.</span></h2> - - -<p>80. It is not my design to examine the -affections of mucous membranes; I shall -notice only some phenomena, which in -these affections I believe deserve a particular -attention, and the explanation of -which I propose to physiological physicians.</p> - -<p>81. Why do mucous membranes seldom -contract adhesions from inflammation, -since that occurs so frequently in serous -surfaces under the same circumstances? -Why does not the internal surface of the<span class="pagenum"><a name="Page_99" id="Page_99">[99]</a></span> -inflamed stomach, intestines, or bladder, -adhere in its various portions like the -pleura, tunica vaginalis, testis, &c.</p> - -<p>82. Why, in inflammations of mucous -membranes, is there an abundant flow of -that fluid which habitually moistens them, -and which constitutes the different kinds -of catarrhs, whilst the source of the fluid -that exhales from serous membranes is -generally dried up in analogous cases?</p> - -<p>83. Why do polypi, a kind of affection -peculiar to mucous membranes, seldom -arise but at the origins of these membranes -in the vicinity of the skin, as in -the nose, pharynx, vagina, &c., and not -in their more internal portions, as in the -stomach, intestines, &c.? Does this arise -from the peculiarity of the texture that I -have shown mucous membranes to have in -the vicinity of those places where they -arise from the skin, or must we attribute -this fact to the more numerous causes of<span class="pagenum"><a name="Page_100" id="Page_100">[100]</a></span> -irritation which act upon the origins of -these cavities?</p> - -<p>84. Are not aphthæ an isolated inflammatory -affection of the glands of the mucous -membranes, whilst catarrhs are characterized -by a general inflammation of all -the parts of these membranes?</p> - - -<p class="p4 pfs80 lsp5">THE END.</p> - -<p class="p4" /> -<hr class="r30a" /> -<p class="pfs80">CHARLES WOOD, Printer,</p> -<p class="pfs90">Poppin's Court, Fleet Street, London.</p> - - - -<hr class="chap" /> - -<div class="footnotes"> -<h2>FOOTNOTES:</h2> - -<div class="footnote"> - -<p><a name="Footnote_A_1" id="Footnote_A_1"></a><a href="#FNanchor_A_1"><span class="label">[A]</span></a> The following questions have been much disputed: -Is there a cystic and an hepatic bile? Is the one of -a different nature from the other? Does their quantity -increase or vary? &c. Contrary, and even opposite, -opinions have been supported by numerous experiments -made upon living animals, as Haller as well observed. -These experiments, though at first sight contradictory, -in reality are not so, as I have had the opportunity of -convincing myself, by repeating them in the different -stages of digestion, and during the abstinence of the -animal, which previously had never been done with -precision. The following are what I have observed in -dogs that I have used in my experiments. (1) During -abstinence, the stomach and the small intestines being -empty, yellowish clear bile was found in the hepatic -duct and ductus communis choledochus; the surface -of the duodenum and jejunum were stained by a bile -which had the same appearance; the gall bladder was -very much distended by a greenish bitter bile, which -was deeper in colour and more in quantity, according -to the length of the abstinence. (2) During the gastric -digestion, which may be prolonged for a sufficient length -of time by giving the dog large pieces of meat, which -he swallows without chewing, appearances were -similar. (3) At the commencement of intestinal -digestion, the bile in the hepatic duct was always found -yellowish; that of the ductus communis choledochus -deeper in colour; the gall bladder not so full, and its -bile becoming already more clear. (4) Towards the -end of digestion, and immediately after it, the bile of -the hepatic duct, of the ductus communis choledochus, -that contained in the gall bladder, and that which was -spread over the duodenum, were exactly of the same -colour as the common hepatic bile, a clear yellow, having -but little bitterness. The gall bladder was but half full; -it was not contracted, but flaccid. -</p> -<p> -These observations, repeated a great number of times, -evidently prove, that such is the manner in which the -bile flows during abstinence and during digestion. (1) It -appears that the liver is continually separating from itself -a sensible quantity of bile, which increases during digestion. -(2) That which is secreted during abstinence -is divided between the intestine, which is always found -coloured with it, and the gall bladder, which retains -it without transmitting any portion of it through the -cystic duct, and where, thus retained, it acquires a -deeper colour and a character of acrimony, necessary, -without doubt, to the digestion which is soon to -follow. (3) When the food, having been digested by -the stomach, passes into the duodenum, then all the -hepatic bile, which was before divided, flows into the -intestine, and even in greater abundance; the gall bladder -also pours that which it contains upon the alimentary -pulp, and with which it is then found quite incorporated. -(4) After the intestinal digestion the hepatic bile diminishes, -and begins to flow, part into the duodenum and -part into the gall bladder, where, being then examined, -it is clear and in small quantity, because it has not yet -had time either to become coloured, or to collect. -</p> -<p> -There is, therefore, this difference between the two -kinds of bile, that the hepatic flows in a continual manner -into the intestine, and the cystic, during the absence of -digestion, flows back into the gall bladder; and whilst -that function is going on it passes towards the duodenum; -or rather it is always the same fluid, of which one part -preserves the character it has when it leaves the liver, -and the other part undergoes a change in the gall bladder. -The difference of colour in the cystic bile, according -to the time that it has remained in the gall bladder, -is analogous to the colour of the urine, which becomes -deeper as it is retained longer in its receptacle.</p></div> - -<div class="footnote"> - -<p><a name="Footnote_B_2" id="Footnote_B_2"></a><a href="#FNanchor_B_2"><span class="label">[B]</span></a> The bile in the gall bladder, the urine in the bladder, -and the semen in the vesicula seminales, are certainly -absorbed; but it is not the fluid itself that re-enters -the circulation, but only its finest parts, some of its principles -that we are not well acquainted with, probably its -aqueous or lymphatic portion. This does not resemble the -absorption in the pleura and other analogous membranes, -in which the fluid rejoins the blood in the same state as -it left it.</p></div> - -<div class="footnote"> - -<p><a name="Footnote_C_3" id="Footnote_C_3"></a><a href="#FNanchor_C_3"><span class="label">[C]</span></a> This is a necessary consequence of the disposition of -the vascular system of the stomach. The arteria coronaria -ventriculi superior being situated transversely between the -stomach and the omentum, and furnishing branches to -both, it is evident, that when the stomach, by separating -the duplicatures of the omentum, lodges itself between -them, and this in applying itself over the stomach becomes -shortened, the branches that it receives from that -artery cannot in the same manner apply themselves to it. -To effect this it would be necessary, that they should -proceed from the one to the other without the intermediate -trunk that cuts them at right angles; then the -stomach, by distending itself, would separate them in the -same way that it does the omentum, and would lodge -between them, instead of pushing them before it with -their common trunk, and folding them upon themselves.</p></div> -</div> - - -<div class="transnote pg-brk"> -<a name="TN" id="TN"></a> -<p><strong>TRANSCRIBER'S NOTE</strong></p> - -<p>Obvious typographical errors and punctuation errors have been -corrected after careful comparison with other occurrences within -the text and consultation of external sources.</p> - -<p>Except for those changes noted below, all misspellings in the text, -and inconsistent or archaic usage, have been retained. For example, -newly-born, newly born; circumvolutions; atmospherical.</p> - -<p> -<a href="#Page_v">Pg v</a> (TOC), page '101' replaced by '98'.<br /> -<a href="#Page_54">Pg 54</a>, 'the mach, small' replaced by 'the stomach, small'.<br /> -<a href="#Page_57">Pg 57</a>, 'membranes is spread' replaced by 'membrane is spread'.<br /> -<a href="#Page_81">Pg 81</a>, 'OF THE SYMPATHY' replaced by 'OF THE SYMPATHIES'.<br /> -<a href="#Page_86">Pg 86</a>, 'fine pelicle' replaced by 'fine pellicle'.<br /> -<a href="#Page_90">Pg 90</a>, 'those asphyxies' replaced by 'those asphyxias'.<br /> -</p> -</div> - - - - - - - - -<pre> - - - - - -End of the Project Gutenberg EBook of Treatise on the Anatomy and Physiology -of the Mucous Membranes, by Xavier Bichat - -*** END OF THIS PROJECT GUTENBERG EBOOK TREATISE ANATOMY OF MUCOUS MEMBRANES *** - -***** This file should be named 52987-h.htm or 52987-h.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/5/2/9/8/52987/ - -Produced by Sonya Schermann, John Campbell and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - -Updated editions will replace the previous one--the old editions will -be renamed. - -Creating the works from print editions not protected by U.S. copyright -law 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. 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