initial commit of ebook 2925HEADmain

2 files changed, 1010 insertions, 0 deletions

diff --git a/old/thx0510.txt b/old/thx0510.txt
new file mode 100644
index 0000000..17042d8
--- /dev/null
+++ b/old/thx0510.txt
@@ -0,0 +1,1010 @@
+***The Project Gutenberg Etext of The Conditions of Existence***
+#15 in our series by Thomas H. Huxley
+
+Copyright laws are changing all over the world, be sure to check
+the laws for your country before redistributing these files!!!
+
+Please take a look at the important information in this header.
+We encourage you to keep this file on your own disk, keeping an
+electronic path open for the next readers.
+
+Please do not remove this.
+
+This should be the first thing seen when anyone opens the book.
+Do not change or edit it without written permission.  The words
+are carefully chosen to provide users with the information they
+need about what they can legally do with the texts.
+
+
+**Welcome To The World of Free Plain Vanilla Electronic Texts**
+
+**Etexts Readable By Both Humans and By Computers, Since 1971**
+
+*These Etexts Prepared By Hundreds of Volunteers and Donations*
+
+Information on contacting Project Gutenberg to get Etexts, and
+further information is included below.  We need your donations.
+
+Presently, contributions are only being solicited from people in:
+Texas, Nevada, Idaho, Montana, Wyoming, Colorado, South Dakota,
+Iowa, Indiana, and Vermont. As the requirements for other states
+are met, additions to this list will be made and fund raising will
+begin in the additional states. These donations should be made to:
+
+Project Gutenberg Literary Archive Foundation
+PMB 113
+1739 University Ave.
+Oxford, MS 38655
+
+
+Title:  The Conditions of Existence
+
+Author:  Thomas H. Huxley
+
+Release Date:  October, 2001  [Etext #XXXX]
+[Yes, we are about one year ahead of schedule]
+
+Edition:  10
+
+***The Project Gutenberg Etext of The Conditions of Existence***
+******This file should be named thx0510.txt or thx0510.zip******
+
+Corrected EDITIONS of our etexts get a new NUMBER, thx0511.txt
+VERSIONS based on separate sources get new LETTER, thx0510a.txt
+
+This etext was prepared by Amy E. Zelmer.
+
+Project Gutenberg Etexts are usually created from multiple editions,
+all of which are in the Public Domain in the United States, unless a
+copyright notice is included.  Therefore, we usually do NOT keep any
+of these books in compliance with any particular paper edition.
+
+We are now trying to release all our books one year in advance
+of the official release dates, leaving time for better editing.
+Please be encouraged to send us error messages even years after
+the official publication date.
+
+Please note:  neither this list nor its contents are final till
+midnight of the last day of the month of any such announcement.
+The official release date of all Project Gutenberg Etexts is at
+Midnight, Central Time, of the last day of the stated month.  A
+preliminary version may often be posted for suggestion, comment
+and editing by those who wish to do so.
+
+Most people start at our sites at:
+http://gutenberg.net
+http://promo.net/pg
+
+
+Those of you who want to download any Etext before announcement
+can surf to them as follows, and just download by date; this is
+also a good way to get them instantly upon announcement, as the
+indexes our cataloguers produce obviously take a while after an
+announcement goes out in the Project Gutenberg Newsletter.
+
+http://metalab.unc.edu/pub/docs/books/gutenberg/etext01
+or
+ftp://metalab.unc.edu/pub/docs/books/gutenberg/etext01
+
+Or /etext00, 99, 98, 97, 96, 95, 94, 93, 92, 92, 91 or 90
+
+Just search by the first five letters of the filename you want,
+as it appears in our Newsletters.
+
+
+Information about Project Gutenberg (one page)
+
+We produce about two million dollars for each hour we work.  The
+time it takes us, a rather conservative estimate, is fifty hours
+to get any etext selected, entered, proofread, edited, copyright
+searched and analyzed, the copyright letters written, etc.  This
+projected audience is one hundred million readers.  If our value
+per text is nominally estimated at one dollar then we produce $2
+million dollars per hour this year as we release fifty new Etext
+files per month, or 500 more Etexts in 2000 for a total of 3000+
+If they reach just 1-2% of the world's population then the total
+should reach over 300 billion Etexts given away by year's end.
+
+The Goal of Project Gutenberg is to Give Away One Trillion Etext
+Files by December 31, 2001.  [10,000 x 100,000,000 = 1 Trillion]
+This is ten thousand titles each to one hundred million readers,
+which is only about 4% of the present number of computer users.
+
+At our revised rates of production, we will reach only one-third
+of that goal by the end of 2001, or about 3,333 Etexts unless we
+manage to get some real funding.
+
+Something is needed to create a future for Project Gutenberg for
+the next 100 years.
+
+We need your donations more than ever!
+
+Presently, contributions are only being solicited from people in:
+Texas, Nevada, Idaho, Montana, Wyoming, Colorado, South Dakota,
+Iowa, Indiana, and Vermont. As the requirements for other states
+are met, additions to this list will be made and fund raising will
+begin in the additional states.
+
+All donations should be made to the Project Gutenberg Literary
+Archive Foundation and will be tax deductible to the extent
+permitted by law.
+
+Mail to:
+
+Project Gutenberg Literary Archive Foundation
+PMB 113
+1739 University Avenue
+Oxford, MS 38655  [USA]
+
+We are working with the Project Gutenberg Literary Archive
+Foundation to build more stable support and ensure the
+future of Project Gutenberg.
+
+We need your donations more than ever!
+
+You can get up to date donation information at:
+
+http://www.gutenberg.net/donation.html
+
+
+***
+
+You can always email directly to:
+
+Michael S. Hart <hart@pobox.com>
+
+hart@pobox.com forwards to hart@prairienet.org and archive.org
+if your mail bounces from archive.org, I will still see it, if
+it bounces from prairienet.org, better resend later on. . . .
+
+We would prefer to send you this information by email.
+
+
+Example command-line FTP session:
+
+ftp metalab.unc.edu
+login: anonymous
+password: your@login
+cd pub/docs/books/gutenberg
+cd etext90 through etext99 or etext00 through etext01, etc.
+dir [to see files]
+get or mget [to get files. . .set bin for zip files]
+GET GUTINDEX.??  [to get a year's listing of books, e.g., GUTINDEX.99]
+GET GUTINDEX.ALL [to get a listing of ALL books]
+
+
+**The Legal Small Print**
+
+
+(Three Pages)
+
+***START**THE SMALL PRINT!**FOR PUBLIC DOMAIN ETEXTS**START***
+Why is this "Small Print!" statement here?  You know: lawyers.
+They tell us you might sue us if there is something wrong with
+your copy of this etext, even if you got it for free from
+someone other than us, and even if what's wrong is not our
+fault.  So, among other things, this "Small Print!" statement
+disclaims most of our liability to you.  It also tells you how
+you can distribute copies of this etext if you want to.
+
+*BEFORE!* YOU USE OR READ THIS ETEXT
+By using or reading any part of this PROJECT GUTENBERG-tm
+etext, you indicate that you understand, agree to and accept
+this "Small Print!" statement.  If you do not, you can receive
+a refund of the money (if any) you paid for this etext by
+sending a request within 30 days of receiving it to the person
+you got it from.  If you received this etext on a physical
+medium (such as a disk), you must return it with your request.
+
+ABOUT PROJECT GUTENBERG-TM ETEXTS
+This PROJECT GUTENBERG-tm etext, like most PROJECT GUTENBERG-tm etexts,
+is a "public domain" work distributed by Professor Michael S. Hart
+through the Project Gutenberg Association (the "Project").
+Among other things, this means that no one owns a United States copyright
+on or for this work, so the Project (and you!) can copy and
+distribute it in the United States without permission and
+without paying copyright royalties.  Special rules, set forth
+below, apply if you wish to copy and distribute this etext
+under the Project's "PROJECT GUTENBERG" trademark.
+
+To create these etexts, the Project expends considerable
+efforts to identify, transcribe and proofread public domain
+works.  Despite these efforts, the Project's etexts and any
+medium they may be on may contain "Defects".  Among other
+things, Defects may take the form of incomplete, inaccurate or
+corrupt data, transcription errors, a copyright or other
+intellectual property infringement, a defective or damaged
+disk or other etext medium, a computer virus, or computer
+codes that damage or cannot be read by your equipment.
+
+LIMITED WARRANTY; DISCLAIMER OF DAMAGES
+But for the "Right of Replacement or Refund" described below,
+[1] the Project (and any other party you may receive this
+etext from as a PROJECT GUTENBERG-tm etext) disclaims all
+liability to you for damages, costs and expenses, including
+legal fees, and [2] YOU HAVE NO REMEDIES FOR NEGLIGENCE OR
+UNDER STRICT LIABILITY, OR FOR BREACH OF WARRANTY OR CONTRACT,
+INCLUDING BUT NOT LIMITED TO INDIRECT, CONSEQUENTIAL, PUNITIVE
+OR INCIDENTAL DAMAGES, EVEN IF YOU GIVE NOTICE OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+If you discover a Defect in this etext within 90 days of
+receiving it, you can receive a refund of the money (if any)
+you paid for it by sending an explanatory note within that
+time to the person you received it from.  If you received it
+on a physical medium, you must return it with your note, and
+such person may choose to alternatively give you a replacement
+copy.  If you received it electronically, such person may
+choose to alternatively give you a second opportunity to
+receive it electronically.
+
+THIS ETEXT IS OTHERWISE PROVIDED TO YOU "AS-IS".  NO OTHER
+WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, ARE MADE TO YOU AS
+TO THE ETEXT OR ANY MEDIUM IT MAY BE ON, INCLUDING BUT NOT
+LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
+PARTICULAR PURPOSE.
+
+Some states do not allow disclaimers of implied warranties or
+the exclusion or limitation of consequential damages, so the
+above disclaimers and exclusions may not apply to you, and you
+may have other legal rights.
+
+INDEMNITY
+You will indemnify and hold the Project, its directors,
+officers, members and agents harmless from all liability, cost
+and expense, including legal fees, that arise directly or
+indirectly from any of the following that you do or cause:
+[1] distribution of this etext, [2] alteration, modification,
+or addition to the etext, or [3] any Defect.
+
+DISTRIBUTION UNDER "PROJECT GUTENBERG-tm"
+You may distribute copies of this etext electronically, or by
+disk, book or any other medium if you either delete this
+"Small Print!" and all other references to Project Gutenberg,
+or:
+
+[1]  Only give exact copies of it.  Among other things, this
+     requires that you do not remove, alter or modify the
+     etext or this "small print!" statement.  You may however,
+     if you wish, distribute this etext in machine readable
+     binary, compressed, mark-up, or proprietary form,
+     including any form resulting from conversion by word
+     processing or hypertext software, but only so long as
+     *EITHER*:
+
+     [*]  The etext, when displayed, is clearly readable, and
+          does *not* contain characters other than those
+          intended by the author of the work, although tilde
+          (~), asterisk (*) and underline (_) characters may
+          be used to convey punctuation intended by the
+          author, and additional characters may be used to
+          indicate hypertext links; OR
+
+     [*]  The etext may be readily converted by the reader at
+          no expense into plain ASCII, EBCDIC or equivalent
+          form by the program that displays the etext (as is
+          the case, for instance, with most word processors);
+          OR
+
+     [*]  You provide, or agree to also provide on request at
+          no additional cost, fee or expense, a copy of the
+          etext in its original plain ASCII form (or in EBCDIC
+          or other equivalent proprietary form).
+
+[2]  Honor the etext refund and replacement provisions of this
+     "Small Print!" statement.
+
+[3]  Pay a trademark license fee to the Project of 20% of the
+     gross profits you derive calculated using the method you
+     already use to calculate your applicable taxes.  If you
+     don't derive profits, no royalty is due.  Royalties are
+     payable to "Project Gutenberg Literary Archive Foundation"
+     the 60 days following each date you prepare (or were
+     legally required to prepare) your annual (or equivalent
+     periodic) tax return.  Please contact us beforehand to
+     let us know your plans and to work out the details.
+
+WHAT IF YOU *WANT* TO SEND MONEY EVEN IF YOU DON'T HAVE TO?
+The Project gratefully accepts contributions of money, time,
+public domain etexts, and royalty free copyright licenses.
+If you are interested in contributing scanning equipment or
+software or other items, please contact Michael Hart at:
+hart@pobox.com
+
+*END THE SMALL PRINT! FOR PUBLIC DOMAIN ETEXTS*Ver.04.07.00*END*
+
+
+
+
+
+This etext was prepared by Amy E. Zelmer.
+
+
+
+
+
+THE CONDITIONS OF EXISTENCE AS AFFECTING THE PERPETUATION OF
+LIVING BEINGS
+
+#15 in our series by Thomas H. Huxley
+
+
+
+
+IN the last Lecture I endeavoured to prove to you that, while, as a
+general rule, organic beings tend to reproduce their kind, there is in
+them, also, a constantly recurring tendency to vary--to vary to a
+greater or to a less extent.  Such a variety, I pointed out to you,
+might arise from causes which we do not understand; we therefore called
+it spontaneous; and it might come into existence as a definite and
+marked thing, without any gradations between itself and the form which
+preceded it.  I further pointed out, that such a variety having once
+arisen, might be perpetuated to some extent, and indeed to a very
+marked extent, without any direct interference, or without any exercise
+of that process which we called selection.  And then I stated further,
+that by such selection, when exercised artificially--if you took care to
+breed only from those forms which presented the same peculiarities of
+any variety which had arisen in this manner--the variation might be
+perpetuated, as far as we can see, indefinitely.
+
+The next question, and it is an important one for us, is this: Is there
+any limit to the amount of variation from the primitive stock which can
+be produced by this process of selective breeding?  In considering this
+question, it will be useful to class the characteristics, in respect of
+which organic beings vary, under two heads: we may consider structural
+characteristics, and we may consider physiological characteristics.
+
+In the first place, as regards structural characteristics, I endeavoured
+to show you, by the skeletons which I had upon the table, and by
+reference to a great many well-ascertained facts, that the different
+breeds of Pigeons, the Carriers, Pouters, and Tumblers, might vary in
+any of their internal and important structural characters to a very
+great degree; not only might there be changes in the proportions of the
+skull, and the characters of the feet and beaks, and so on; but that
+there might be an absolute difference in the number of the vertebrae of
+the back, as in the sacral vertebrae of the Pouter; and so great is the
+extent of the variation in these and similar characters that I pointed
+out to you, by reference to the skeletons and the diagrams, that these
+extreme varieties may absolutely differ more from one another in their
+structural characters than do what naturalists call distinct SPECIES of
+pigeons; that is to say, that they differ so much in structure that
+there is a greater difference between the Pouter and the Tumbler than
+there is between such wild and distinct forms as the Rock Pigeon or the
+Ring Pigeon, or the Ring Pigeon and the Stock Dove; and indeed the
+differences are of greater value than this, for the structural
+differences between these domesticated pigeons are such as would be
+admitted by a naturalist, supposing he knew nothing at all about their
+origin, to entitle them to constitute even distinct genera.
+
+As I have used this term SPECIES, and shall probably use it a good deal,
+I had better perhaps devote a word or two to explaining what I mean by
+it.
+
+Animals and plants are divided into groups, which become gradually
+smaller, beginning with a KINGDOM, which is divided into SUB-KINGDOMS;
+then come the smaller divisions called PROVINCES; and so on from a
+PROVINCE to a CLASS from a CLASS to an ORDER, from ORDERS to FAMILIES,
+and from these to GENERA, until we come at length to the smallest
+groups of animals which can be defined one from the other by constant
+characters, which are not sexual; and these are what naturalists call
+SPECIES in practice, whatever they may do in theory.
+
+If, in a state of nature, you find any two groups of living beings,
+which are separated one from the other by some constantly-recurring
+characteristic, I don't care how slight and trivial, so long as it is
+defined and constant, and does not depend on sexual peculiarities, then
+all naturalists agree in calling them two species; that is what is
+meant by the use of the word species--that is to say, it is, for the
+practical naturalist, a mere question of structural differences.*
+
+    [footnote]* I lay stress here on the 'practical'
+    signification of "Species."  Whether a physiological test
+    between species exist or not, it is hardly ever applicable
+    by the practical naturalist.
+
+We have seen now--to repeat this point once more, and it is very
+essential that we should rightly understand it--we have seen that
+breeds, known to have been derived from a common stock by selection,
+may be as different in their structure from the original stock as
+species may be distinct from each other.
+
+But is the like true of the physiological characteristics of animals?
+Do the physiological differences of varieties amount in degree to those
+observed between forms which naturalists call distinct species?  This
+is a most important point for us to consider.
+
+As regards the great majority of physiological characteristics, there is
+no doubt that they are capable of being developed, increased, and
+modified by selection.
+
+There is no doubt that breeds may be made as different as species in
+many physiological characters.  I have already pointed out to you very
+briefly the different habits of the breeds of Pigeons, all of which
+depend upon their physiological peculiarities,--as the peculiar habit
+of tumbling, in the Tumbler--the peculiarities of flight, in the
+"homing" birds,--the strange habit of spreading out the tail, and
+walking in a peculiar fashion, in the Fantail,--and, lastly, the habit
+of blowing out the gullet, so characteristic of the Pouter. These are
+all due to physiological modifications, and in all these respects these
+birds differ as much from each other as any two ordinary species do.
+
+So with Dogs in their habits and instincts.  It is a physiological
+peculiarity which leads the Greyhound to chase its prey by sight,--that
+enables the Beagle to track it by the scent,--that impels the Terrier
+to its rat-hunting propensity,--and that leads the Retriever to its
+habit of retrieving.  These habits and instincts are all the results of
+physiological differences and peculiarities, which have been developed
+from a common stock, at least there is every reason to believe so.  But
+it is a most singular circumstance, that while you may run through
+almost the whole series of physiological processes, without finding a
+check to your argument, you come at last to a point where you do find a
+check, and that is in the reproductive processes. For there is a most
+singular circumstance in respect to natural species--at least about some
+of them--and it would be sufficient for the purposes of this argument
+if it were true of only one of them, but there is, in fact, a great
+number of such cases--and that is, that, similar as they may appear to
+be to mere races or breeds, they present a marked peculiarity in the
+reproductive process. If you breed from the male and female of the same
+race, you of course have offspring of the like kind, and if you make
+the offspring breed together, you obtain the same result, and if you
+breed from these again, you will still have the same kind of offspring;
+there is no check. But if you take members of two distinct species,
+however similar they may be to each other and make them breed together,
+you will find a check, with some modifications and exceptions, however,
+which I shall speak of presently.  If you cross two such species with
+each other, then,--although you may get offspring in the case of the
+first cross, yet, if you attempt to breed from the products of that
+crossing, which are what are called HYBRIDS--that is, if you couple a
+male and a female hybrid--then the result is that in ninety-nine cases
+out of a hundred you will get no offspring at all; there will be no
+result whatsoever.
+
+The reason of this is quite obvious in some cases; the male hybrids,
+although possessing all the external appearances and characteristics of
+perfect animals, are physiologically imperfect and deficient in the
+structural parts of the reproductive elements necessary to generation.
+It is said to be invariably the case with the male mule, the cross
+between the Ass and the Mare; and hence it is, that, although crossing
+the Horse with the Ass is easy enough, and is constantly done, as far
+as I am aware, if you take two mules, a male and a female, and endeavour
+to breed from them, you get no offspring whatever; no generation will
+take place.  This is what is called the sterility of the hybrids
+between two distinct species.
+
+You see that this is a very extraordinary circumstance; one does not see
+why it should be.  The common teleological explanation is, that it is
+to prevent the impurity of the blood resulting from the crossing of one
+species with another, but you see it does not in reality do anything of
+the kind.  There is nothing in this fact that hybrids cannot breed with
+each other, to establish such a theory; there is nothing to prevent the
+Horse breeding with the Ass, or the Ass with the Horse.  So that this
+explanation breaks down, as a great many explanations of this kind do,
+that are only founded on mere assumptions.
+
+Thus you see that there is a great difference between "mongrels," which
+are crosses between distinct races, and "hybrids," which are crosses
+between distinct species.  The mongrels are, so far as we know, fertile
+with one another.  But between species, in many cases, you cannot
+succeed in obtaining even the first cross: at any rate it is quite
+certain that the hybrids are often absolutely infertile one with
+another.
+
+Here is a feature, then, great or small as it may be, which
+distinguishes natural species of animals.  Can we find any
+approximation to this in the different races known to be produced by
+selective breeding from a common stock?  Up to the present time the
+answer to that question is absolutely a negative one.  As far as we
+know at present, there is nothing approximating to this check.  In
+crossing the breeds between the Fantail and the Pouter, the Carrier and
+the Tumbler, or any other variety or race you may name--so far as we
+know at present--there is no difficulty in breeding together the
+mongrels.  Take the Carrier and the Fantail, for instance, and let them
+represent the Horse and the Ass in the case of distinct species; then
+you have, as the result of their breeding, the Carrier-Fantail
+mongrel,--we will say the male and female mongrel,--and, as far as we
+know, these two when crossed would not be less fertile than the
+original cross, or than Carrier with Carrier.  Here, you see, is a
+physiological contrast between the races produced by selective
+modification and natural species.  I shall inquire into the value of
+this fact, and of some modifying circumstances by and by; for the
+present I merely put it broadly before you.
+
+But while considering this question of the limitations of species, a
+word must be said about what is called RECURRENCE--the tendency of
+races which have been developed by selective breeding from varieties to
+return to their primitive type.  This is supposed by many to put an
+absolute limit to the extent of selective and all other variations.
+People say, "It is all very well to talk about producing these
+different races, but you know very well that if you turned all these
+birds wild, these Pouters, and Carriers, and so on, they would all
+return to their primitive stock."  This is very commonly assumed to be
+a fact, and it is an argument that is commonly brought forward as
+conclusive; but if you will take the trouble to inquire into it rather
+closely, I think you will find that it is not worth very much.  The
+first question of course is, Do they thus return to the primitive
+stock?  And commonly as the thing is assumed and accepted, it is
+extremely difficult to get anything like good evidence of it.  It is
+constantly said, for example, that if domesticated Horses are turned
+wild, as they have been in some parts of Asia Minor and South America,
+that they return at once to the primitive stock from which they were
+bred. But the first answer that you make to this assumption is, to ask
+who knows what the primitive stock was; and the second answer is, that
+in that case the wild Horses of Asia Minor ought to be exactly like the
+wild Horses of South America.  If they are both like the same thing,
+they ought manifestly to be like each other!  The best authorities,
+however, tell you that it is quite different.  The wild Horse of Asia
+is said to be of a dun colour, with a largish head, and a great many
+other peculiarities; while the best authorities on the wild Horses of
+South America tell you that there is no similarity between their wild
+Horses and those of Asia Minor; the cut of their heads is very
+different, and they are commonly chestnut or bay-coloured.  It is quite
+clear, therefore, that as by these facts there ought to have been two
+primitive stocks, they go for nothing in support of the assumption that
+races recur to one primitive stock, and so far as this evidence is
+concerned, it falls to the ground.
+
+Suppose for a moment that it were so, and that domesticated races, when
+turned wild, did return to some common condition, I cannot see that
+this would prove much more than that similar conditions are likely to
+produce similar results; and that when you take back domesticated
+animals into what we call natural conditions, you do exactly the same
+thing as if you carefully undid all the work you had gone through, for
+the purpose of bringing the animal from its wild to its domesticated
+state.  I do not see anything very wonderful in the fact, if it took
+all that trouble to get it from a wild state, that it should go back
+into its original state as soon as you removed the conditions which
+produced the variation to the domesticated form. There is an important
+fact, however, forcibly brought forward by Mr. Darwin, which has been
+noticed in connection with the breeding of domesticated pigeons; and it
+is, that however different these breeds of pigeons may be from each
+other, and we have already noticed the great differences in these
+breeds, that if, among any of those variations, you chance to have a
+blue pigeon turn up, it will be sure to have the black bars across the
+wings, which are characteristic of the original wild stock, the Rock
+Pigeon.
+
+Now, this is certainly a very remarkable circumstance; but I do not see
+myself how it tells very strongly either one way or the other.  I
+think, in fact, that this argument in favour of recurrence to the
+primitive type might prove a great deal too much for those who so
+constantly bring it forward.  For example, Mr. Darwin has very forcibly
+urged, that nothing is commoner than if you examine a dun horse--and I
+had an opportunity of verifying this illustration lately, while in the
+islands of the West Highlands, where there are a great many dun
+horses--to find that horse exhibit a long black stripe down his back,
+very often stripes on his shoulder, and very often stripes on his
+legs.  I, myself, saw a pony of this description a short time ago, in a
+baker's cart, near Rothesay, in Bute: it had the long stripe down the
+back, and stripes on the shoulders and legs, just like those of the
+Ass, the Quagga, and the Zebra.  Now, if we interpret the theory of
+recurrence as applied to this case, might it not be said that here was
+a case of a variation exhibiting the characters and conditions of an
+animal occupying something like an intermediate position between the
+Horse, the Ass, the Quagga, and the Zebra, and from which these had
+been developed?  In the same way with regard even to Man. Every
+anatomist will tell you that there is nothing commoner, in dissecting
+the human body, than to meet with what are called muscular
+variations--that is, if you dissect two bodies very carefully, you will
+probably find that the modes of attachment and insertion of the muscles
+are not exactly the same in both, there being great peculiarities in
+the mode in which the muscles are arranged; and it is very singular,
+that in some dissections of the human body you will come upon
+arrangements of the muscles very similar indeed to the same parts in the
+Apes.  Is the conclusion in that case to be, that this is like the
+black bars in the case of the Pigeon, and that it indicates a
+recurrence to the primitive type from which the animals have been
+probably developed?  Truly, I think that the opponents of modification
+and variation had better leave the argument of recurrence alone, or it
+may prove altogether too strong for them.
+
+To sum up,--the evidence as far as we have gone is against the argument
+as to any limit to divergences, so far as structure is concerned; and
+in favour of a physiological limitation.  By selective breeding we can
+produce structural divergences as great as those of species, but we
+cannot produce equal physiological divergences.  For the present I leave
+the question there.
+
+Now, the next problem that lies before us--and it is an extremely
+important one--is this: Does this selective breeding occur in nature?
+Because, if there is no proof of it, all that I have been telling you
+goes for nothing in accounting for the origin of species.  Are natural
+causes competent to play the part of selection in perpetuating
+varieties?  Here we labour under very great difficulties.  In the last
+lecture I had occasion to point out to you the extreme difficulty of
+obtaining evidence even of the first origin of those varieties which we
+know to have occurred in domesticated animals.  I told you, that almost
+always the origin of these varieties is overlooked, so that I could
+only produce two of three cases, as that of Gratio Kelleia and of the
+Ancon sheep.  People forget, or do not take notice of them until they
+come to have a prominence; and if that is true of artificial cases,
+under our own eyes, and in animals in our own care, how much more
+difficult it must be to have at first hand good evidence of the origin
+of varieties in nature!  Indeed, I do not know that it is possible by
+direct evidence to prove the origin of a variety in nature, or to prove
+selective breeding; but I will tell you what we can prove--and this
+comes to the same thing--that varieties exist in nature within the
+limits of species, and, what is more, that when a variety has come into
+existence in nature, there are natural causes and conditions, which are
+amply competent to play the part of a selective breeder; and although
+that is not quite the evidence that one would like to have--though it
+is not direct testimony--yet it is exceeding good and exceedingly
+powerful evidence in its way.
+
+As to the first point, of varieties existing among natural species, I
+might appeal to the universal experience of every naturalist, and of
+any person who has ever turned any attention at all to the
+characteristics of plants and animals in a state of nature; but I may as
+well take a few definite cases, and I will begin with Man himself.
+
+I am one of those who believe that, at present, there is no evidence
+whatever for saying, that mankind sprang originally from any more than
+a single pair; I must say, that I cannot see any good ground whatever,
+or even any tenable sort of evidence, for believing that there is more
+than one species of Man.  Nevertheless, as you know, just as there are
+numbers of varieties in animals, so there are remarkable varieties of
+men.  I speak not merely of those broad and distinct variations which
+you see at a glance.  Everybody, of course, knows the difference
+between a Negro and a white man, and can tell a Chinaman from an
+Englishman.  They each have peculiar characteristics of colour and
+physiognomy; but you must recollect that the characters of these races
+go very far deeper--they extend to the bony structure, and to the
+characters of that most important of all organs to us--the brain; so
+that, among men belonging to different races, or even within the same
+race, one man shall have a brain a third, or half, or even seventy per
+cent. bigger than another; and if you take the whole range of human
+brains, you will find a variation in some cases of a hundred per cent.
+Apart from these variations in the size of the brain, the characters of
+the skull vary.  Thus if I draw the figures of a Mongul and of a Negro
+head on the blackboard, in the case of the last the breadth would be
+about seven-tenths, and in the other it would be nine-tenths of the
+total length.  So that you see there is abundant evidence of variation
+among men in their natural condition.  And if you turn to other animals
+there is just the same thing.  The fox, for example, which has a very
+large geographical distribution all over Europe, and parts of Asia, and
+on the American Continent, varies greatly.  There are mostly large
+foxes in the North, and smaller ones in the South.  In Germany alone,
+the foresters reckon some eight different sorts.
+
+Of the tiger, no one supposes that there is more than one species; they
+extend from the hottest parts of Bengal, into the dry, cold, bitter
+steppes of Siberia, into a latitude of 50 degrees,--so that they may
+even prey upon the reindeer.  These tigers have exceedingly different
+characteristics, but still they all keep their general features, so that
+there is no doubt as to their being tigers.  The Siberian tiger has a
+thick fur, a small mane, and a longitudinal stripe down the back, while
+the tigers of Java and Sumatra differ in many important respects from
+the tigers of Northern Asia.  So lions vary; so birds vary; and so, if
+you go further back and lower down in creation, you find that fishes
+vary.  In different streams, in the same country even, you will find
+the trout to be quite different to each other and easily recognisable by
+those who fish in the particular streams.  There is the same
+differences in leeches; leech collectors can easily point out to you
+the differences and the peculiarities which you yourself would probably
+pass by; so with fresh-water mussels; so, in fact, with every animal
+you can mention.
+
+In plants there is the same kind of variation.  Take such a case even as
+the common bramble. The botanists are all at war about it; some of them
+wanting to make out that there are many species of it, and others
+maintaining that they are but many varieties of one species; and they
+cannot settle to this day which is a species and which is a variety!
+
+So that there can be no doubt whatsoever that any plant and any animal
+may vary in nature; that varieties may arise in the way I have
+described,--as spontaneous varieties,--and that those varieties may be
+perpetuated in the same way that I have shown you spontaneous varieties
+are perpetuated; I say, therefore, that there can be no doubt as to the
+origin and perpetuation of varieties in nature.
+
+But the question now is:--Does selection take place in nature?  is there
+anything like the operation of man in exercising selective breeding,
+taking place in nature?  You will observe that, at present, I say
+nothing about species; I wish to confine myself to the consideration of
+the production of those natural races which everybody admits to exist.
+The question is, whether in nature there are causes competent to
+produce races, just in the same way as man is able to produce by
+selection, such races of animals as we have already noticed.
+
+When a variety has arisen, the CONDITIONS OF EXISTENCE are such as to
+exercise an influence which is exactly comparable to that of artificial
+selection.  By Conditions of Existence I mean two things,--there are
+conditions which are furnished by the physical, the inorganic world,
+and there are conditions of existence which are furnished by the
+organic world.  There is, in the first place, CLIMATE; under that head
+I include only temperature and the varied amount of moisture of
+particular places.  In the next place there is what is technically
+called STATION, which means--given the climate, the particular kind of
+place in which an animal or a plant lives or grows; for example, the
+station of a fish is in the water, of a fresh-water fish in fresh
+water; the station of a marine fish is in the sea, and a marine animal
+may have a station higher or deeper.  So again with land animals: the
+differences in their stations are those of different soils and
+neighbourhoods; some being best adapted to a calcareous, and others to
+an arenaceous soil.  The third condition of existence is FOOD, by which
+I mean food in the broadest sense, the supply of the materials necessary
+to the existence of an organic being; in the case of a plant the
+inorganic matters, such as carbonic acid, water, ammonia, and the
+earthy salts or salines; in the case of the animal the inorganic and
+organic matters, which we have seen they require; then these are all,
+at least the two first, what we may call the inorganic or physical
+conditions of existence.  Food takes a mid-place, and then come the
+organic conditions; by which I mean the conditions which depend upon the
+state of the rest of the organic creation, upon the number and kind of
+living beings, with which an animal is surrounded.  You may class these
+under two heads: there are organic beings, which operate as
+'opponents', and there are organic beings which operate as 'helpers' to
+any given organic creature.  The opponents may be of two kinds: there
+are the 'indirect opponents', which are what we may call 'rivals'; and
+there are the 'direct opponents', those which strive to destroy the
+creature; and these we call 'enemies'. By rivals I mean, of course, in
+the case of plants, those which require for their support the same kind
+of soil and station, and, among animals, those which require the same
+kind of station, or food, or climate; those are the indirect opponents;
+the direct opponents are, of course, those which prey upon an animal or
+vegetable.  The 'helpers' may also be regarded as direct and indirect:
+in the case of a carnivorous animal, for example, a particular
+herbaceous plant may in multiplying be an indirect helper, by enabling
+the herbivora on which the carnivore preys to get more food, and thus
+to nourish the carnivore more abundantly; the direct helper may be best
+illustrated by reference to some parasitic creature, such as the
+tape-worm.  The tape-worm exists in the human intestines, so that the
+fewer there are of men the fewer there will be of tape-worms, other
+things being alike.  It is a humiliating reflection, perhaps, that we
+may be classed as direct helpers to the tape-worm, but the fact is so:
+we can all see that if there were no men there would be no tape-worms.
+
+It is extremely difficult to estimate, in a proper way, the importance
+and the working of the Conditions of Existence.  I do not think there
+were any of us who had the remotest notion of properly estimating them
+until the publication of Mr. Darwin's work, which has placed them
+before us with remarkable clearness; and I must endeavour, as far as I
+can in my own fashion, to give you some notion of how they work.  We
+shall find it easiest to take a simple case, and one as free as
+possible from every kind of complication.
+
+I will suppose, therefore, that all the habitable part of this
+globe--the dry land, amounting to about 51,000,000 square miles,--I
+will suppose that the whole of that dry land has the same climate, and
+that it is composed of the same kind of rock or soil, so that there will
+be the same station everywhere; we thus get rid of the peculiar
+influence of different climates and stations. I will then imagine that
+there shall be but one organic being in the world, and that shall be a
+plant.  In this we start fair.  Its food is to be carbonic acid, water
+and ammonia, and the saline matters in the soil, which are, by the
+supposition, everywhere alike.  We take one single plant, with no
+opponents, no helpers, and no rivals; it is to be a "fair field, and no
+favour".  Now, I will ask you to imagine further that it shall be a
+plant which shall produce every year fifty seeds, which is a very
+moderate number for a plant to produce; and that, by the action of the
+winds and currents, these seeds shall be equally and gradually
+distributed over the whole surface of the land.  I want you now to
+trace out what will occur, and you will observe that I am not talking
+fallaciously any more than a mathematician does when he expounds his
+problem.  If you show that the conditions of your problem are such as
+may actually occur in nature and do not transgress any of the known
+laws of nature in working out your proposition, then you are as safe in
+the conclusion you arrive at as is the mathematician in arriving at the
+solution of his problem.  In science, the only way of getting rid of the
+complications with which a subject of this kind is environed, is to
+work in this deductive method.  What will be the result, then?  I will
+suppose that every plant requires one square foot of ground to live
+upon; and the result will be that, in the course of nine years, the
+plant will have occupied every single available spot in the whole
+globe!  I have chalked upon the blackboard the figures by which I
+arrive at the result:-
+
+Plants.                                                Plants
+                  1 x 50 in 1st year =                     50
+                 50 x 50 "  2nd   "  =                  2,500
+              2,500 x 50 "  3rd   "  =                125,000
+            125,000 x 50 "  4th   "  =              6,250,000
+          6,250,000 x 50 "  5th   "  =            312,500,000
+        312,500,000 x 50 "  6th   "  =         15,625,000,000
+     15,625,000,000 x 50 "  7th   "  =        781,250,000,000
+    781,250,000,000 x 50 "  8th   "  =     39,062,500,000,000
+39,062,500,000,000 x 50& "  9th   "  =  1,953,125,000,000,000
+
+51,000,000 sq. miles--the dry surface of the earth x 27,878,400--the
+number of sq. ft. in 1 sq.  mile = sq. ft. 1,421,798,400,000,000 being
+531,326,600,000,000 square feet less than would be required at the end
+of the ninth year.
+
+You will see from this that, at the end of the first year the single
+plant will have produced fifty more of its kind; by the end of the
+second year these will have increased to 2,500; and so on, in
+succeeding years, you get beyond even trillions; and I am not at all
+sure that I could tell you what the proper arithmetical denomination of
+the total number really is; but, at any rate, you will understand the
+meaning of all those noughts.  Then you see that, at the bottom, I have
+taken the 51,000,000 of square miles, constituting the surface of the
+dry land; and as the number of square feet are placed under and
+subtracted from the number of seeds that would be produced in the ninth
+year, you can see at once that there would be an immense number more of
+plants than there would be square feet of ground for their
+accommodation.  This is certainly quite enough to prove my point; that
+between the eighth and ninth year after being planted the single plant
+would have stocked the whole available surface of the earth.
+
+This is a thing which is hardly conceivable--it seems hardly
+imaginable--yet it is so.  It is indeed simply the law of Malthus
+exemplified.  Mr. Malthus was a clergyman, who worked out this subject
+most minutely and truthfully some years ago; he showed quite
+clearly,--and although he was much abused for his conclusions at the
+time, they have never yet been disproved and never will be--he showed
+that in consequence of the increase in the number of organic beings in
+a geometrical ratio, while the means of existence cannot be made to
+increase in the same ratio, that there must come a time when the number
+of organic beings will be in excess of the power of production of
+nutriment, and that thus some check must arise to the further increase
+of those organic beings.  At the end of the ninth year we have seen that
+each plant would not be able to get its full square foot of ground, and
+at the end of another year it would have to share that space with fifty
+others the produce of the seeds which it would give off.
+
+What, then, takes place?  Every plant grows up, flourishes, occupies its
+square foot of ground, and gives off its fifty seeds; but notice this,
+that out of this number only one can come to anything; there is thus,
+as it were, forty-nine chances to one against its growing up; it
+depends upon the most fortuitous circumstances whether any one of these
+fifty seeds shall grow up and flourish, or whether it shall die and
+perish.  This is what Mr. Darwin has drawn attention to, and called the
+"STRUGGLE FOR EXISTENCE"; and I have taken this simple case of a plant
+because some people imagine that the phrase seems to imply a sort of
+fight.
+
+I have taken this plant and shown you that this is the result of the
+ratio of the increase, the necessary result of the arrival of a time
+coming for every species when exactly as many members must be destroyed
+as are born; that is the inevitable ultimate result of the rate of
+production.  Now, what is the result of all this?  I have said that
+there are forty-nine struggling against every one; and it amounts to
+this, that the smallest possible start given to any one seed may give
+it an advantage which will enable it to get ahead of all the others;
+anything that will enable any one of these seeds to germinate six hours
+before any of the others will, other things being alike, enable it to
+choke them out altogether.  I have shown you that there is no
+particular in which plants will not vary from each other; it is quite
+possible that one of our imaginary plants may vary in such a character
+as the thickness of the integument of its seeds; it might happen that
+one of the plants might produce seeds having a thinner integument, and
+that would enable the seeds of that plant to germinate a little quicker
+than those of any of the others, and those seeds would most inevitably
+extinguish the forty-nine times as many that were struggling with them.
+
+I have put it in this way, but you see the practical result of the
+process is the same as if some person had nurtured the one and
+destroyed the other seeds.  It does not matter how the variation is
+produced, so long as it is once allowed to occur.  The variation in the
+plant once fairly started tends to become hereditary and reproduce
+itself; the seeds would spread themselves in the same way and take part
+in the struggle with the forty-nine hundred, or forty-nine thousand,
+with which they might be exposed.  Thus, by degrees, this variety, with
+some slight organic change or modification, must spread itself over the
+whole surface of the habitable globe, and extirpate or replace the
+other kinds.  That is what is meant by NATURAL SELECTION; that is the
+kind of argument by which it is perfectly demonstrable that the
+conditions of existence may play exactly the same part for natural
+varieties as man does for domesticated varieties.  No one doubts at all
+that particular circumstances may be more favourable for one plant and
+less so for another, and the moment you admit that, you admit the
+selective power of nature.  Now, although I have been putting a
+hypothetical case, you must not suppose that I have been reasoning
+hypothetically.  There are plenty of direct experiments which bear out
+what we may call the theory of natural selection; there is extremely
+good authority for the statement that if you take the seed of mixed
+varieties of wheat and sow it, collecting the seed next year and sowing
+it again, at length you will find that out of all your varieties only
+two or three have lived, or perhaps even only one.  There were one or
+two varieties which were best fitted to get on, and they have killed
+out the other kinds in just the same way and with just the same
+certainty as if you had taken the trouble to remove them.  As I have
+already said, the operation of nature is exactly the same as the
+artificial operation of man.
+
+But if this be true of that simple case, which I put before you, where
+there is nothing but the rivalry of one member of a species with
+others, what must be the operation of selective conditions, when you
+recollect as a matter of fact, that for every species of animal or
+plant there are fifty or a hundred species which might all, more or
+less, be comprehended in the same climate, food, and station;--that
+every plant has multitudinous animals which prey upon it, and which are
+its direct opponents; and that these have other animals preying upon
+them,--that every plant has its indirect helpers in the birds that
+scatter abroad its seed, and the animals that manure it with their
+dung;--I say, when these things are considered, it seems impossible
+that any variation which may arise in a species in nature should not
+tend in some way or other either to be a little better or worse than
+the previous stock; if it is a little better it will have an advantage
+over and tend to extirpate the latter in this crush and struggle; and if
+it is a little worse it will itself be extirpated.
+
+I know nothing that more appropriately expresses this, than the phrase,
+"the struggle for existence"; because it brings before your minds, in a
+vivid sort of way, some of the simplest possible circumstances
+connected with it.  When a struggle is intense there must be some who
+are sure to be trodden down, crushed, and overpowered by others; and
+there will be some who just manage to get through only by the help of
+the slightest accident.  I recollect reading an account of the famous
+retreat of the French troops, under Napoleon, from Moscow.  Worn out,
+tired, and dejected, they at length came to a great river over which
+there was but one bridge for the passage of the vast army. Disorganised
+and demoralised as that army was, the struggle must certainly have been
+a terrible one--every one heeding only himself, and crushing through
+the ranks and treading down his fellows.  The writer of the narrative,
+who was himself one of those who were fortunate enough to succeed in
+getting over, and not among the thousands who were left behind or
+forced into the river, ascribed his escape to the fact that he saw
+striding onward through the mass a great strong fellow,--one of the
+French Cuirassiers, who had on a large blue cloak--and he had enough
+presence of mind to catch and retain a hold of this strong man's
+cloak.  He says, "I caught hold of his cloak, and although he swore at
+me and cut at and struck me by turns, and at last, when he found he
+could not shake me off, fell to entreating me to leave go or I should
+prevent him from escaping, besides not assisting myself, I still kept
+tight hold of him, and would not quit my grasp until he had at last
+dragged me through."  Here you see was a case of selective saving--if
+we may so term it--depending for its success on the strength of the
+cloth of the Cuirassier's cloak.  It is the same in nature; every
+species has its bridge of Beresina; it has to fight its way through and
+struggle with other species; and when well nigh overpowered, it may be
+that the smallest chance, something in its colour, perhaps--the
+minutest circumstance--will turn the scale one way or the other.
+
+Suppose that by a variation of the black race it had produced the white
+man at any time--you know that the Negroes are said to believe this to
+have been the case, and to imagine that Cain was the first white man,
+and that we are his descendants--suppose that this had ever happened,
+and that the first residence of this human being was on the West Coast
+of Africa.  There is no great structural difference between the white
+man and the Negro, and yet there is something so singularly different
+in the constitution of the two, that the malarias of that country, which
+do not hurt the black at all, cut off and destroy the white.  Then you
+see there would have been a selective operation performed; if the white
+man had risen in that way, he would have been selected out and removed
+by means of the malaria.  Now there really is a very curious case of
+selection of this sort among pigs, and it is a case of selection of
+colour too.  In the woods of Florida there are a great many pigs, and
+it is a very curious thing that they are all black, every one of them.
+Professor Wyman was there some years ago, and on noticing no pigs but
+these black ones, he asked some of the people how it was that they had
+no white pigs, and the reply was that in the woods of Florida there was
+a root which they called the Paint Root, and that if the white pigs
+were to eat any of it, it had the effect of making their hoofs crack,
+and they died, but if the black pigs eat any of it, it did not hurt
+them at all.  Here was a very simple case of natural selection.  A
+skilful breeder could not more carefully develope the black breed of
+pigs, and weed out all the white pigs, than the Paint Root does.
+
+To show you how remarkably indirect may be such natural selective
+agencies as I have referred to, I will conclude by noticing a case
+mentioned by Mr. Darwin, and which is certainly one of the most curious
+of its kind.  It is that of the Humble Bee.  It has been noticed that
+there are a great many more humble bees in the neighbourhood of towns,
+than out in the open country; and the explanation of the matter is
+this: the humble bees build nests, in which they store their honey and
+deposit the larvae and eggs.  The field mice are amazingly fond of the
+honey and larvae; therefore, wherever there are plenty of field mice, as
+in the country, the humble bees are kept down; but in the neighbourhood
+of towns, the number of cats which prowl about the fields eat up the
+field mice, and of course the more mice they eat up the less there are
+to prey upon the larvae of the bees--the cats are therefore the INDIRECT
+HELPERS of the bees!*  Coming back a step farther we may say that the
+old maids are also indirect friends of the humble bees, and indirect
+enemies of the field mice, as they keep the cats which eat up the
+latter!  This is an illustration somewhat beneath the dignity of the
+subject, perhaps, but it occurs to me in passing, and with it I will
+conclude this lecture.
+
+[footnote] *The humble bees, on the other hand, are direct helpers of
+some plants, such as the heartsease and red clover, which are
+fertilized by the visits of the bees; and they are indirect helpers of
+the numerous insects which are more or less completely supported by the
+heartsease and red clover.
+
+
+
+
+
+End of The Project Gutenberg Etext of The Conditions of Existence
+by Thomas H. Huxley
+
diff --git a/old/thx0510.zip b/old/thx0510.zip
new file mode 100644
index 0000000..8c1161d
--- /dev/null
+++ b/old/thx0510.zip