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diff --git a/old/65779-0.txt b/old/65779-0.txt deleted file mode 100644 index bdb512b..0000000 --- a/old/65779-0.txt +++ /dev/null @@ -1,7312 +0,0 @@ -The Project Gutenberg eBook, Charles Darwin and the Theory of Natural -Selection, by Sir Edward Bagnall Poulton - - -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: Charles Darwin and the Theory of Natural Selection - - -Author: Sir Edward Bagnall Poulton - - - -Release Date: July 6, 2021 [eBook #65779] - -Language: English - -Character set encoding: UTF-8 - - -***START OF THE PROJECT GUTENBERG EBOOK CHARLES DARWIN AND THE THEORY OF -NATURAL SELECTION*** - - -E-text prepared by Fay Dunn, Charlie Howard, and the Online Distributed -Proofreading Team (http://www.pgdp.net) from page images generously made -available by Internet Archive (https://archive.org) - - - -Note: Project Gutenberg also has an HTML version of this - file which includes the original illustration. - See 65779-h.htm or 65779-h.zip: - (http://www.gutenberg.org/files/65779/65779-h/65779-h.htm) - or - (http://www.gutenberg.org/files/65779/65779-h.zip) - - - Images of the original pages are available through - Internet Archive. See - https://archive.org/details/charlesdarwinthe00poulrich - - -Transcriber’s Note - - Text enclosed by underscores is in italics (_italics_). - - A caret character is used to denote superscription. A - single character following the caret is superscripted - (example: individ^l). Multiple superscripted characters are - enclosed by curly brackets (example: affect^{te}). - - - - - -THE CENTURY SCIENCE SERIES - -Edited by Sir Henry E. Roscoe, D.C.L., LL.D., F.R.S. - - - -CHARLES DARWIN -AND THE THEORY OF NATURAL SELECTION - - - * * * * * * - -The Century Science Series. - -EDITED BY - -SIR HENRY E. ROSCOE, D.C.L., F.R.S. - - -John Dalton and the Rise of Modern Chemistry. - - By Sir HENRY E. ROSCOE, F.R.S., &c. - - -Major Rennell, F.R.S., and the Rise of Modern English Geography. - - By Sir CLEMENTS R. MARKHAM, C.B., F.R.S., President of the Royal - Geographical Society. - - -Justus von Liebig: his Life and Work (1803–1873). - - By W. A. SHENSTONE, F.I.C., Lecturer on Chemistry in Clifton College. - - -The Herschels and Modern Astronomy. - - By AGNES M. CLERKE, Author of “A Popular History of Astronomy during - the 19th Century,” &c. - - -Charles Lyell and Modern Geology. - - By Professor T. G. BONNEY, F.R.S., &c. - - -James Clerk Maxwell and Modern Physics. - - By R. T. GLAZEBROOK, F.R.S., Fellow of Trinity College, Cambridge. - - -Humphry Davy, Poet and Philosopher. - - By T. E. THORPE, LL.D., F.R.S. - - -Charles Darwin and the Theory of Natural Selection. - - By EDWARD B. POULTON, M.A., F.R.S., Hope Professor of Zoology at the - University of Oxford, &c. - - -_In Preparation._ - -Michael Faraday: his Life and Work. - - By Professor SILVANUS P. THOMPSON, F.R.S. - - -Pasteur: his Life and Work. - - By M. ARMAND RUFFER, M.D., Director of the British Institute of - Preventive Medicine. - - -Hermann von Helmholtz. - - By A. W. RÜCKER, F.R.S., Professor of Physics in the Royal College of - Science, London. - - -CASSELL & COMPANY, LIMITED, _London; Paris & Melbourne_. - - * * * * * * - - -[Illustration: - - _Photo by Mr. James C. Christie, F.G.S., Glasgow._ - -STATUE OF CHARLES DARWIN. - -(_By Boehm._) - -CENTRAL HALL OF THE BRITISH MUSEUM OF NATURAL HISTORY.] - - -The Century Science Series - -CHARLES DARWIN -AND THE THEORY OF NATURAL SELECTION - -by - -EDWARD B. POULTON -M.A., F.R.S., F.G.S., F.L.S., ETC. - -Hope Professor of Zoology at the University of Oxford -Corresp. Memb. of the New York Academy of Sciences -Corresp. Memb. of the Boston Society of Nat. Hist. - - - - - - -Cassell and Company, Limited -London, Paris & Melbourne -1896 -All Rights Reserved - - -[Illustration] - - - - -INTRODUCTION - - -In the following pages I have tried to express a sense of the greatness -of my subject by simplicity and directness of statement. The limits -of the work necessarily prevented any detailed treatment, the subject -of the work prevented originality. We have had the great “Life and -Letters” with us for nine years, and this I have used as a mine, -extracting what I believed to be the statements of chief importance for -the work in hand, and grouping them so as to present what I hope is -a connected account of Darwin’s life, when considered in relation to -his marvellous work; and especially to the great central discovery of -Natural Selection and its exposition in the “Origin of Species.” - -In addition to the invaluable volumes which we owe to the industry, -taste, and skill of Francis Darwin, an immense number of other works -have been consulted. We live in an age of writing, and of speeches and -addresses; and the many sides of Darwin’s life and work have again and -again inspired the ablest men of our time to write and speak their -best--a justification for the freedom with which quotations are spread -over the following pages. - -It is my pleasant duty to express my hearty thanks to many kind friends -who have helped in the production of this little work. Mr. Francis -Darwin has kindly permitted the use of many of Darwin’s letters, -which have not as yet been published, and he has given me valuable -information and criticism on many points. I have also gained much -by discussion and correspondence with my friends Dr. A. R. Wallace, -Professor E. Ray Lankester, and Professor Meldola. The latter has -freely given me the use of his valuable series of letters; and I owe -to my friend, Mr. Rowland H. Wedgwood, the opportunity of publishing a -single letter of very great interest. - -The greater part of the volume formed the subject of two short courses -of lectures delivered in the Hope Department of the Oxford University -Museum in Michaelmas Term 1894 and Lent Term 1895. - - EDWARD B. POULTON. - -Oxford, _October, 1896_. - - - - -CONTENTS - - - CHAPTER PAGE - - I.--THE SECRET OF DARWIN’S GREATNESS 9 - - II.--BOYHOOD--EDINBURGH--CAMBRIDGE (1817–31) 16 - - III.--VOYAGE OF THE “BEAGLE” (1831–36) 21 - - IV.--CAMBRIDGE--LONDON--WORK UPON THE - COLLECTIONS--MARRIAGE--GEOLOGICAL WORK--JOURNAL OF - THE VOYAGE--CORAL REEFS--FIRST RECORDED THOUGHTS ON - EVOLUTION (1837–42) 25 - - V.--DOWN--GEOLOGY OF THE VOYAGE--WORK ON CIRRIPEDES (1842–54) 35 - - VI.--THE GROWTH OF THE “ORIGIN OF SPECIES” (1837–58) 42 - - VII.--GROWTH OF THE “ORIGIN” (_continued_)--CORRESPONDENCE WITH - FRIENDS 50 - - VIII.--DARWIN AND WALLACE (1858) 60 - - IX.--DARWIN’S SECTION OF THE JOINT MEMOIR READ BEFORE THE - LINNEAN SOCIETY JULY 1, 1858 65 - - X.--WALLACE’S SECTION OF THE JOINT MEMOIR READ BEFORE THE - LINNEAN SOCIETY JULY 1, 1858 71 - - XI.--COMPARISON OF DARWIN’S AND WALLACE’S SECTIONS OF THE JOINT - MEMOIR--RECEPTION OF THEIR VIEWS--THEIR FRIENDSHIP 78 - - XII.--THE GROWTH OF WALLACE’S CONVICTIONS ON EVOLUTION AND - DISCOVERY OF NATURAL SELECTION--BORNEO 1855--TERNATE - 1858 87 - - XIII.--CANON TRISTRAM THE FIRST PUBLICLY TO ACCEPT THE THEORY - OF NATURAL SELECTION (1859) 92 - - XIV.--THE PREPARATION OF THE “ORIGIN OF SPECIES” (1858–59) 95 - - XV.--THE ORIGIN OF SPECIES (1859) 100 - - XVI.--THE INFLUENCE OF DARWIN UPON LYELL (1859–64) 105 - - XVII.--INFLUENCE OF DARWIN UPON HOOKER AND ASA GRAY--NATURAL - SELECTION AND DESIGN IN NATURE (1860–68) 111 - - XVIII.--INFLUENCE OF DARWIN UPON HUXLEY 119 - - XIX.--THE DIFFICULTY WITH WHICH THE “ORIGIN” WAS UNDERSTOOD 144 - - XX.--THE DIFFICULTY WITH WHICH THE “ORIGIN” WAS UNDERSTOOD - (_continued_)--VIEWS ON SPONTANEOUS GENERATION 153 - - XXI.--VARIATION OF ANIMALS AND PLANTS UNDER DOMESTICATION: - PANGENESIS (1868) 161 - - XXII.--PANGENESIS AND CONTINUITY OF THE GERM-PLASM: DARWIN’S - CONFIDENCE IN PANGENESIS 178 - - XXIII.--DESCENT OF MAN--EXPRESSION OF EMOTIONS--EARTH-WORMS - (1871–81) 186 - - XXIV.--BOTANICAL WORKS (1862–86) 193 - - XXV.--LETTERS FROM DARWIN TO PROFESSOR MELDOLA (1871–82) 199 - - XXVI.--HIS LAST ILLNESS (1882) 219 - - INDEX 221 - - - - - CHARLES DARWIN - AND - THE THEORY OF NATURAL SELECTION. - - - - -CHAPTER I. - -THE SECRET OF DARWIN’S GREATNESS. - - -Charles Robert Darwin was born at Shrewsbury on February 12th, 1809, -the year which witnessed the birth of Alfred Tennyson, W. E. Gladstone, -and Abraham Lincoln. - -Oliver Wendell Holmes, born in the same year, delighted to speak of the -good company in which he came into the world. On January 27th, 1894, -I had the great pleasure of sitting next to him at a dinner of the -Saturday Club in Boston, and he then spoke of the subject with the same -enthusiasm with which he deals with it in his writings; mentioning the -four distinguished names, and giving a brief epigrammatic description -of each with characteristic felicity. Dr. Holmes further said that he -remembered with much satisfaction an occasion on which he was able to -correct Darwin on a matter of scientific fact. He could not remember -the details, but we may hope for their ultimate recovery, for he said -that Darwin had written a courteous reply accepting the correction. - -[Sidenote: HIS FAMILY.] - -Charles Darwin’s grandfather, Erasmus Darwin (1731–1802), was a man of -great genius. He speculated upon the origin of species, and arrived at -views which were afterwards independently enunciated by Lamarck. He -resembled this great zoologist in fertility of imagination, and also in -the boldness with which he put forward suggestions, many of which were -crude and entirely untested by an appeal to facts. The poetical form in -which a part of his work was written was, doubtless, largely due to the -traditions and customs of the age in which he lived. - -Robert Waring (1766–1848), the father of Charles Darwin, was the second -son of Erasmus. He married a daughter of the great Josiah Wedgwood. -Although his mother died when he was only eight years old, and Darwin -remembered very little of her, there is evidence that she directed his -attention to Nature (“Autobiography,” p. 28, footnote). Dr. Darwin -followed his father’s profession, commencing a very successful medical -practice at Shrewsbury before he was twenty-one. He was a man of great -penetration, especially in the discernment of character--a power which -was of the utmost value to him in his profession. Dr. Darwin had two -sons and four daughters: Charles was the younger son and fourth child, -his brother Erasmus being the third. - -Even in this mere outline there is evidence of hereditary genius -in the Darwin family--evidence which becomes irresistible when all -available details of every member of the family are brought together, -as they are in the great “Life and Letters.” When it is further -remembered that two of Charles Darwin’s sons have achieved distinction -as scientific investigators, it will be admitted that the history of -the family affords a most striking example of hereditary intellectual -power. - -There is nothing in this history to warrant the belief that the nature -and direction of hereditary genius receive any bias from the line of -intellectual effort pursued by a parent. We recognise the strongest -evidence for hereditary capacity, but none at all for the transmission -of results which follow the employment of capacity. Thus Erasmus -inherited high intellectual power, with a bias entirely different from -that of his younger brother Charles--his interests being literary -and artistic rather than scientific. The wide difference between the -brothers seems to have made a great impression upon Charles, for he -wrote:-- - - “Our minds and tastes were, however, so different, that I do not - think I owe much to him intellectually. I am inclined to agree - with Francis Galton in believing that education and environment - produce only a small effect on the mind of anyone, and that most - of our qualities are innate” (“Life and Letters,” 1887, p. 22). - -Equally significant is the fact that Professor George Darwin’s -important researches in mathematics have been applied to -astronomy--subjects which were not pursued by his father. - -[Sidenote: CHARACTER AND POWERS.] - -It appears probable that Charles Darwin’s unique power was largely -due to the inheritance of the imagination of his grandfather combined -with the acute observation of his father. Although he possessed an -even larger share of both these qualities than his predecessors, it -is probable that he owed more to their co-operation than to the high -degree of their development. - -It is a common error to suppose that the intellectual powers which -make the poet or the historian are essentially different from those -which make the man of science. Powers of observation, however acute, -could never make a scientific discoverer; for discovery requires the -creative effort of the imagination. The scientific man does not stumble -upon new facts or conclusions by accident; he finds what he looks for. -The problem before him is essentially similar to that of the historian -who tries to create an accurate and complete picture of an epoch out -of scattered records of contemporary impressions more or less true, -and none wholly true. Fertility of imagination is absolutely essential -for that step from the less to the more perfectly known which we call -discovery. - -But fertility of imagination alone is insufficient for the highest -achievement in poetry, history, or science; for in all these subjects -the strictest self-criticism and the soundest judgment are necessary -in order to ensure that the results are an advance in the direction -of the truth. A delicately-adjusted balance between the powers of -imagination and the powers which hold imagination in check, is -essential in the historian who is to provide us with a picture of a -past age, which explains the mistaken impression gained by a more or -less prejudiced observer who saw but a small part of it from a limited -standpoint, and has handed down his impression to us. A poem which -sheds new light upon the relation between mind and mind, requires to -be tested and controlled by constant and correct observation, like a -hypothesis in the domain of the natural sciences. - -It is probable, then, that the secret of Darwin’s strength lay in the -perfect balance between his powers of imagination and those of accurate -observation, the creative efforts of the one being ever subjected to -the most relentless criticism by the employment of the other. We shall -never know, I have heard Professor Michael Foster say, the countless -hypotheses which passed through the mind of Darwin, and which, however -wild and improbable, were tested by an appeal to Nature, and were then -dismissed for ever. - -Darwin’s estimate of his own powers is given with characteristic -candour and modesty in the concluding paragraph of his “Autobiography” -(“Life and Letters,” 1887, p. 107):-- - - “Therefore my success as a man of science, whatever this - may have amounted to, has been determined, as far as I can - judge, by complex and diversified mental qualities and - conditions. Of these, the most important have been--the love - of science--unbounded patience in long reflecting over any - subject--industry in observing and collecting facts--and a fair - share of invention as well as of common sense. With such moderate - abilities as I possess, it is truly surprising that I should have - influenced to a considerable extent the belief of scientific men - on some important points.” - -We also know from other sources that Darwin looked upon the creative -powers as essential to scientific progress. Thus he wrote to Wallace -in 1857: “I am a firm believer that without speculation there is no -good and original observation.” He also says in the “Autobiography”: -“I have steadily endeavoured to keep my mind free so as to give up any -hypothesis, however much beloved (and I cannot resist forming one on -every subject), as soon as facts are shown to be opposed to it.” - -[Sidenote: VALUE OF HYPOTHESIS.] - -I have thought it worth while to insist thus strongly on the high value -attached by Darwin to hypothesis, controlled by observation, in view -of certain recent attacks upon this necessary weapon for scientific -advance. Thus Bateson, in his “Materials for the Study of Variation” -(London, 1894), p. 7, says: “In the old time the facts of Nature -were beautiful in themselves and needed not the rouge of speculation -to quicken their charm, but that was long ago before Modern Science -was born.” The author does not specify the period in the history of -science when discovery proceeded without hypothesis. A study of the -earlier volumes of the _Philosophical Transactions_ reveals a far -greater interest in speculation than in the facts of Nature. We can -hardly call those ages anything but speculative which received with -approval the suggestions that geese were developed from barnacles which -grew upon trees; that swallows hibernated at the bottom of lakes; -that the Trade-winds were due to the breath of a sea-weed. Bateson’s -statement requires to be reversed in order to become correct. Modern -science differs from the science of long ago in its greater attention -to the facts of Nature and its more rigid control over the tendency -to hypothesis; although hypothesis remains, and must ever remain, as -the guide and inspirer of observation and the discovery of fact.[A] -Although Darwin has kindled the imagination of hundreds of workers, and -has thus been the cause of an immense amount of speculation, science -owes him an even larger debt for the innumerable facts discovered under -the guidance of this faculty. - - - - -CHAPTER II. - -BOYHOOD--EDINBURGH--CAMBRIDGE (1817–31). - - -Of Darwin’s boyhood and school-life we only know the facts given in his -brief “Autobiography,” written when he was sixty-seven, together with -those collected by his son Francis and appended in the form of notes. -He first went to Mr. Case’s day-school in Shrewsbury in 1817, the year -of his mother’s death. At this time, although only eight years old, his -interest in natural history and in collecting was well established. -“The passion for collecting, which leads a man to be a systematic -naturalist, a virtuoso, or a miser, was very strong in me, and was -clearly innate, as none of my sisters or brother had this taste.” - -In the following year he went to Dr. Butler’s school in Shrewsbury, -where he remained seven years. He does not appear to have profited -much by the classical instruction which at that time received -almost exclusive attention. His interest seems to have been chiefly -concentrated upon sport; but whenever a subject attracted him he -worked hard at it, and it is probable that he would have conveyed a -very different impression of his powers to the masters and his father -if scientific subjects had been taught, as they are now to a moderate -extent in many schools. - -That he was a keen observer for his age is clear from the fact that, -when he was only ten, he was much interested and surprised to notice -that the insects he found on the Welsh coast were different from those -in Shropshire. His most valuable education was received out of school -hours--collecting, and working at chemistry with his brother Erasmus, -although this latter study drew down upon him the rebukes of Dr. Butler -for wasting time on such useless subjects. - -[Sidenote: AT EDINBURGH.] - -He was removed from school early, and in 1825 went to Edinburgh to -study medicine--a subject for which he seemed to be unfitted by nature. -The methods of instruction by lectures did not benefit him; he was -disgusted at dissection, and could not endure to witness an operation. -And yet here it was evident, as it became afterwards at Cambridge, -that Darwin--although seeming to be by no means above the average when -judged by ordinary standards--possessed in reality a very remarkable -and attractive personality. There can be no other explanation of the -impression he made upon distinguished men who were much older than -himself, and the friendships he formed with those of his own age who -were afterwards to become eminent. - -Thus at Edinburgh he was well acquainted with Dr. Grant and Mr. -Macgillivray, the curator of the museum, and worked at marine zoology -in company with the former. Here, too, in 1826, he made his first -scientific discovery, and read a paper before the Plinian Society, -proving that so-called eggs of Flustra were in reality free-swimming -larvæ. And it is evident from his “Autobiography” that he took every -opportunity of hearing and learning about scientific subjects. - -Darwin’s love of sport remained as keen as ever at this period and at -Cambridge, and he speaks with especial enthusiasm of his visits in the -autumn to Maer, the home of his uncle, Josiah Wedgwood, who afterwards -exerted so important an influence upon his life. - -[Sidenote: AT CAMBRIDGE.] - -After Darwin had been at Edinburgh for two sessions, his father -realised that he did not like the thought of the medical profession, -and suggested that he should become a clergyman. With this intention -he was sent to Cambridge in the beginning of 1828, after spending some -months in recovering the classics he had learnt at school. - -He joined Christ’s College, and passed his final examination in -January, 1831, being tenth in the list of those who do not seek -honours. The immense, and in many respects disastrous, development -of the competitive examination system since that time has almost -banished from our universities the type of student represented by -Darwin--the man who takes the easiest road to a degree and obtains it -with the minimum of effort, but who all the time is being benefited by -residence, studying, without any thought of examinations, the subjects -which are of special interest to him, and seeking personal contact -with older men who have reached the highest eminence in those subjects. - -He seems to have led a somewhat double life at Cambridge, his -intense love of sport taking him into a pleasure-loving set, while -his intellectual interests made him the intimate friend of Whitley, -who became Senior Wrangler, and of Professor Henslow, to whom he -was introduced by his second cousin, W. Darwin Fox, who also first -interested him in entomology. He became so keen a collector of beetles -that his successes and experiences in this direction seem to have -impressed him more deeply than anything else at Cambridge. Entomology, -and especially beetles, form the chief subject of those of his -Cambridge letters which have been recovered. - -Darwin’s friendship with Henslow, which was to have a most important -effect on his life, very soon deepened. They often went long walks -together, so that he was called “the man who walks with Henslow.” This -fact and the subsequent rapidly formed intimacy with Professor Adam -Sedgwick, indicate that he was remarkable among the young men of his -standing. - -One of his undergraduate friends, J. M. Herbert, afterwards County -Court Judge for South Wales, retained the most vivid recollection of -Darwin at Cambridge, and contributed the following impression of his -character to the “Life and Letters”:-- - - “It would be idle for me to speak of his vast intellectual powers - ... but I cannot end this cursory and rambling sketch without - testifying, and I doubt not all his surviving college friends - would concur with me, that he was the most genial, warm-hearted, - generous and affectionate of friends; that his sympathies were - with all that was good and true; and that he had a cordial - hatred for everything false, or vile, or cruel, or mean, or - dishonourable. He was not only great, but pre-eminently good, and - just, and loveable.” - -Two books greatly influenced Darwin--Herschel’s “Introduction to the -Study of Natural Philosophy,” which, he said, “stirred up in me a -burning zeal to add even the most humble contribution to the noble -structure of Natural Science”; and Humboldt’s “Personal Narrative,” -which roused in him the longing to travel--a desire which was soon -afterwards gratified by his voyage in the _Beagle_. - -“Upon the whole,” he says, “the three years which I spent at Cambridge -were the most joyful in my happy life; for I was then in excellent -health, and almost always in high spirits.” - -After passing his last examination, Darwin had still two terms’ -residence to keep, and was advised by Henslow to study geology. To -this end Henslow asked Sedgwick to allow Darwin to go with him on a -geological excursion in North Wales in August, 1831. He thus gained -experience which was of the utmost value during the voyage of the -_Beagle_. - - - - -CHAPTER III. - -VOYAGE OF THE “BEAGLE” (1831–36). - - -About the time of the excursion with Sedgwick (the exact date is -uncertain) Professor Henslow received a letter from George Peacock -(formerly Dean of Ely and Lowndean Professor of Astronomy at Cambridge) -stating that he had the offer to recommend a young man as naturalist -to accompany Captain Fitzroy on a surveying expedition to many parts -of the world. Leonard Jenyns (afterwards Blomefield) was evidently -considered to be the most suitable person for the position, but he -was unable to accept it. Henslow at once wrote (August 24th, 1831) to -Darwin, and advised him to do his utmost to obtain the position, and -Darwin found the letter waiting for him on his return home after the -geological excursion with Sedgwick. As his father greatly disliked the -idea, Darwin at once wrote (August 30th) and declined, and the next -day went to Maer to be ready for the shooting on September 1st. Here, -however, his uncle, Josiah Wedgwood, took a very different view from -that adopted by his father, with the result that both he and Darwin -wrote (August 31st) to Shrewsbury and reopened the question. Darwin’s -letter shows the most touching deference to his father’s wishes, and -the gravest apprehension lest he should be rendered “uncomfortable” or -“uneasy” by any further suggestion as to the possibility of the voyage, -although his father had said, “If you can find any man of common-sense -who advises you to go, I will give my consent.” We also learn from the -“Autobiography” that his uncle sent for him whilst out shooting and -drove him the thirty miles to Shrewsbury, in order that they might talk -with his father, who then at once consented. This must have been on -September 1st, 1831. - -From this time until he went to Plymouth, on October 24th--the final -start was not until December 27th--his letters show that he had a very -busy time making purchases and preparing for the voyage. These letters -breathe the warmest affection to the members of his family and his -friends, together with the keenest enthusiasm for Captain Fitzroy, the -ship, and the voyage. - -The voyage of the _Beagle_ lasted from December 27th, 1831, to October -2nd, 1836. Darwin says that it was “by far the most important event in -my life, and has determined my whole career.... I have always felt that -I owe to the voyage the first real training or education of my mind” -(_l. c._, p. 61). He attributes the greatest share in this training to -geology, among the special sciences, because of the reasoning involved -in making out the structure of a new and unknown district; but he -considers that the habits of “energetic industry and of concentrated -attention” which he then acquired were of the utmost importance, and -the secret of all his success in science. He tells us that the love of -sport was present at first in all its keenness, but that he gradually -abandoned it for scientific work. - -Among his numerous observations and discoveries during the voyage, -those which appear to stand out in his mind so that he quotes them -in his “Autobiography” are--the explanation of the forms of coral -islands, the geological structure of St. Helena and other islands, and -the relations between the animals and plants of the several Galapagos -islands to each other and to those of South America. His letters and -the collections which he sent home attracted much attention; and -Sedgwick told Dr. Darwin that his son would take a place among the -leading scientific men. When Darwin heard this from his sisters, he -says, “I clambered over the mountains of Ascension with a bounding -step, and made the volcanic rocks resound under my geological hammer.” -His letters during the voyage are full of enthusiasm and of longing to -return to his family and friends. - -There was the same conflict between the naval and scientific -departments of the _Beagle_ on the untidiness of the decks which was -afterwards repeated on the _Challenger_, where I have been told that -one of the naval authorities used to say, with resigned disgust, “Oh, -no, we’re not a man-of-war, we’re only a ---- dredger!” - -In the course of the voyage the following countries and islands were -visited in the order given:--The Cape de Verde Islands, St. Paul’s -Rocks, Fernando Noronha, South America (including the Galapagos -Archipelago, the Falkland Islands, and Tierra del Fuego), Tahiti, New -Zealand, Australia, Tasmania, Keeling Island, Maldive Coral Atolls, -Mauritius, St. Helena, Ascension. Brazil was then visited again for a -short time, the _Beagle_ touching at the Cape de Verde Islands and the -Azores on the voyage home. - -Darwin says, concerning the intellectual effect of his work during the -voyage:-- - - “That my mind became developed through my pursuits during the - voyage is rendered probable by a remark made by my father, who - was the most acute observer whom I ever saw, of a sceptical - disposition, and far from being a believer in phrenology; for on - first seeing me after the voyage he turned round to my sisters, - and exclaimed, ‘Why the shape of his head is quite altered!’” - (_l. c._, pp. 63, 64). - - - - -CHAPTER IV. - -CAMBRIDGE--LONDON--WORK UPON THE COLLECTIONS--MARRIAGE--GEOLOGICAL -WORK--JOURNAL OF THE VOYAGE--CORAL REEFS--FIRST RECORDED THOUGHTS ON -EVOLUTION (1837–42). - - -Darwin reached England October 2nd, 1836, and was home at Shrewsbury -October 5th (according to his Letters; the 4th is the date given by -Francis Darwin in the “Life and Letters”). The two years and three -months which followed he describes as the most active ones he ever -spent. After visiting his family, he stayed three months in Cambridge, -working at his collection of rocks, writing his “Naturalist’s Voyage,” -and one or two scientific papers. He then (March 7th, 1837) took -lodgings in 36, Great Marlborough Street, London, where he remained -until his marriage, January 29th, 1839. The apathy of scientific -men--even those in charge of museums--caused him much depression, -and he found great difficulty in getting specialists to work out his -collections, although the botanists seem to have been keener than the -zoologists. - -The commencement of his London residence is of the deepest interest, -as the time at which he began to reflect seriously on the origin of -species. Thus he says in the “Autobiography”:--“In July I opened my -first note-book for facts in relation to the Origin of Species, about -which I had long reflected, and never ceased working for the next -twenty years.” Furthermore, his pocket-book for 1837 contained the -words:--“In July opened first note-book on Transmutation of Species. -Had been greatly struck from about the month of previous March” (he was -then just over twenty-eight years old) “on character of South American -fossils, and species on Galapagos Archipelago. These facts (especially -latter) origin of all my views.” It is, perhaps, worth while to -explain in greater detail the nature of this evidence which appealed -so strongly to Darwin’s mind. The Edentata (sloths, ant-eaters, -armadilloes, etc.) have their metropolis in South America, and in the -later geological formations of this country the skeletons of gigantic -extinct animals of the same order (Megatherium, Mylodon, Glyptodon, -etc.) are found; and Darwin was doubtless all the more impressed by -discovering such remains for himself. In his “Autobiography” he says: -“During the voyage of the _Beagle_ I had been deeply impressed by -discovering in the Pampean formation great fossil animals covered with -armour like that on existing armadilloes;...” - -Darwin was thus led to conclude that there was some genetic connection -between the animals which have succeeded each other in the same -district; for in a theory of destructive cataclysms, followed by -re-creations--or, indeed, in any theory of special creation--there -seemed no adequate reason why the successive forms should belong -to the same order. In his “Naturalist’s Voyage Round the World” he -says, speaking of this subject: “This wonderful relationship in the -same continent between the dead and the living will, I do not doubt, -hereafter throw more light on the appearance of organic beings on our -earth, and their disappearance from it, than any other class of facts” -(p. 173 in the third edition). - -[Sidenote: THE GALAPAGOS.] - -The other class of evidence which impressed him even more strongly -was afforded by the relations between the animals and plants of the -several islands of the Galapagos Archipelago and between those of -the Archipelago and of South America, nearly 600 miles to the East. -Although the inhabitants of the separate islands show an astonishing -amount of peculiarity, the species are nearly related, and also exhibit -American affinities. Concerning this, Darwin writes in his “Voyage” -(p. 398 in the third edition): “Reviewing the facts here given, one -is astonished at the amount of creative force--if such an expression -may be used--displayed on these small, barren, and rocky islands; and -still more so at its diverse and yet analogous action on points so near -each other.” Here, too, the facts were unintelligible on a theory of -separate creation of species, but were at once explained if we suppose -that the inhabitants were the modified descendants of species which -had migrated from South America--the migrations to the Archipelago and -between the separate islands being rendered extremely rare from the -depth of the sea, the direction of the currents, and the absence of -gales. In this way time for specific modification was provided before -the partially modified form could interbreed with the parent species -and thus lose its own newly-acquired characteristics. - -Although Darwin made these observations on the _Beagle_, they -required, as Huxley has suggested (Obituary [1888], “Darwiniana”: -Collected Essays, vol. ii., pp. 274–275. London, 1893), careful and -systematic working out before they could be trusted as a basis on -which to speculate; and this could not be done until the return home. -The following letter written by Darwin to Dr. Otto Zacharias in 1877 -confirms this opinion. It was sent to Huxley by Francis Darwin, and is -printed in “Darwiniana” (_l. c._, p. 275):-- - - “When I was on board the ‘Beagle,’ I believed in the permanence - of species, but, as far as I can remember, vague doubts - occasionally flitted across my mind. On my return home in the - autumn of 1836, I immediately began to prepare my journal for - publication, and then saw how many facts indicated the common - descent of species, so that in July, 1837, I opened a note-book - to record any facts which might bear on the question. But I did - not become convinced that species were mutable until I think two - or three years had elapsed.” - -It is interesting to note that both the lines of evidence which -appealed to Darwin so strongly, point to evolution, but not to any -causes of evolution. The majority of mankind were only convinced of -this process when some conception as to its causes had been offered to -them; Darwin took the more logical course of first requiring evidence -that the process takes place, and then inquiring for its causes. - -[Sidenote: EARLY NOTES ON SPECIES.] - -The first indication of these thoughts in any of his published letters -is in one to his cousin Fox written in June, 1838, in which, after -alluding to some questions he had previously asked about the crossing -of animals, he says, “It is my prime hobby, and I really think some day -I shall be able to do something in that most intricate subject--species -and varieties.” - -He is rather more definite in a letter to Sir Charles Lyell, written -September 13th in the same year:-- - - “I have lately been sadly tempted to be idle--that is, as far - as pure geology is concerned--by the delightful number of new - views which have been coming in thickly and steadily,--on the - classification and affinities and instincts of animals--bearing - on the question of species. Note-book after note-book has been - filled with facts which begin to group themselves _clearly_ under - sub-laws.” - -On February 16th, 1838, he was appointed Secretary of the Geological -Society, a position which he retained until February 1st, 1841. During -these two years after the voyage he saw much of Sir Charles Lyell, -whose teachings had been of the greatest help to him during the -voyage, and whose method of appealing to natural causes rather than -supernatural cataclysms undoubtedly had a most important influence -on the development of Darwin’s mind. This influence he delighted to -acknowledge, dedicating to Lyell the second edition of his “Voyage,” -“as an acknowledgment that the chief part of whatever scientific merit -this ‘Journal’ and the other works of the author may possess has been -derived from studying the well-known and admirable ‘Principles of -Geology.’” - -[Sidenote: EARLY WORKS.] - -At this period he finished his “Journal,” which was published in -1839 as Vol. III. of the “Narrative of the Surveying Voyages of Her -Majesty’s Ships _Adventure_ and _Beagle_.” A second edition was -published in a separate form in 1845 as the “Journal of Researches into -the Natural History and Geology of the Countries visited during the -Voyage of H.M.S. _Beagle_ round the World, under the command of Captain -Fitz-Roy, R.N.”; and a third edition--but very slightly altered--in -1860, under the title “A Naturalist’s Voyage: Journal of Researches, -etc.” This book is generally admitted to deserve above all others the -generous description which Darwin gave to Sir Joseph Hooker of Belt’s -admirable “Naturalist in Nicaragua”--as “the best of all Natural -History journals which have ever been published.” - -A comparison between the first and second editions indicates, but by -no means expresses, his growing convictions on evolution and natural -selection. Natural selection he had not discovered when the MS. of the -first edition was complete; and if we had no further evidence we could -not, from any passage in the work, maintain that he was convinced of -evolution. His great caution in dealing with so tremendous a problem -explains why the second edition does not reflect the state of his mind -at the time of its publication. He tells us (“Autobiography”) that in -the preparation of this second edition he “took much pains,” and we may -feel confident that much of this care was given to the decision as to -how much he should reveal and how much withhold of the thoughts which -were occupying his mind, and the conclusions to which he had at that -time arrived. That he did attribute much importance to the evolutionary -passages added in the second edition is shown by his letter to Lyell -(July, 1845), in which he alludes to some of them, and specially asks -Lyell to read the pages on the causes of extinction. - -He also edited and superintended the “Zoology of the Voyage of H.M.S. -_Beagle_,” the special parts of which were written by various eminent -systematists, and appeared separately between 1839 and 1843. - -He also read several papers before the Geological Society, including -two (1838 and 1840) on the Formation of Mould by the Action of -Earth-Worms--a subject to which he returned, and upon which his last -volume (published in 1881) was written. He also read a paper on the -Parallel Roads of Glen Roy before the Royal Society (published in -the _Phil. Trans._, 1839). These wonderful parallel terraces are now -admitted to be due to the changes of level in a lake following those of -an ice-barrier at the mouth of the valley. At the time Darwin studied -them, the terraces were believed to have been formed by a lake dammed -back by a barrier of rock and alluvium; this he proved to be wrong, and -as no other barrier was then available--for the evidences of glaciation -had not then been discovered by Agassiz--he was driven, on the method -of exclusion, to the action of the sea. Upon this subject he says, in -the “Autobiography,” “My error has been a good lesson to me never to -trust in science to the principle of exclusion.” - -On January 29th, 1839, he married his cousin, Emma Wedgwood, the -daughter of Josiah Wedgwood, of Maer. They resided at 12, Upper Gower -Street until September 14th, 1842, when they settled at Down. - -The few graceful and touching words in which Francis Darwin, in the -“Life and Letters,” alludes to his father’s married life show how deep -is the debt of gratitude which the world owes to Mrs. Darwin; for -without her constant and loving care it would have been impossible for -Darwin to have accomplished his life-work. - -[Sidenote: ON CORAL REEFS.] - -During these years in London his health broke down many times; so that -he says, in the “Autobiography”: “I did less scientific work, though I -worked as hard as I possibly could, than during any other equal length -of time in my life.” He chiefly worked at his book on “The Structure -and Distribution of Coral Reefs,” published in 1842 (second edition in -1874). This work contains an account of Darwin’s well-known theory upon -the origin of the various coral formations--fringing reefs, barrier -reefs, and atolls--by the upward growth of the reef keeping pace with -the gradual sinking of the island upon which it is based, so that the -living corals always remain at the surface under the most favourable -conditions, while beneath them is an ever-thickening reef formed of -dead coral, until at length, by continuing this process, the climax -is reached in the atoll, in which the original island has altogether -disappeared beneath the surface of a central lagoon enclosed in a -ring formed by the living edge of the reef. This theory, after being -accepted for many years, has recently been disputed, chiefly as the -result of the observations made on the _Challenger_ expedition. It -is contended by Dr. John Murray “that it is not necessary to call in -subsidence to explain any of the characteristic features of barrier -reefs or atolls, and that all these features would exist alike in areas -of slow elevation, of rest, or of slow subsidence” (_Nature_, August -12th, 1880, p. 337). It cannot be said that this controversy is yet -settled, or that the supporters of either theory have proved that the -other does not hold--at any rate, in certain cases. - -Among his geological papers written at this time was one describing the -glacial phenomena observed during a tour in North Wales. This paper -(_Philosophical Magazine_, 1842, p. 352) is placed by Sir Archibald -Geikie “almost at the top of the long list of English contributions to -the history of the Ice Age.” - -At this time, too, he was reflecting and collecting evidence for -the great work of his life. Thus in January, 1841, he writes to his -cousin, Darwin Fox, asking for “all kinds of facts about ‘Varieties and -Species.’” - - - - -CHAPTER V. - -DOWN--GEOLOGY OF THE VOYAGE--WORK ON CIRRIPEDES (1842–54). - - -From September 14th, 1842, until his death, Darwin resided at Down, -living a very retired life, and almost exclusively engaged in his -scientific researches. Although Down is only twenty miles from London, -it is three miles from the nearest railway station (Orpington), and is -only now for the first time receiving a telegraph office. A home in -such a place enabled Darwin to pursue his work without interruption, -remaining, at the same time, within easy reach of all the advantages of -London. Here, too, he had no difficulty in avoiding social engagements, -which always injured his very precarious health, and thus interfered -with work; although, at the same time, he could entertain in his own -house at such times as he felt able to do so. - -In 1844, and again in 1846, he published works on the geology of the -voyage of the _Beagle_; the first on the Volcanic Islands visited, the -second on South America. A second edition, in which both were combined -in a single work, appeared in 1876. He seemed somewhat disappointed -at the small amount of attention they at first attracted, and wrote -with much humour to J. M. Herbert:--“I have long discovered that -geologists never read each other’s works, and that the only object in -writing a book is a proof of earnestness, and that you do not form -your opinions without undergoing labour of some kind.” All geologists -were, nevertheless, soon agreed in attaching the highest value to these -researches. - -[Sidenote: ON CIRRIPEDES.] - -From this time forward his work was almost exclusively zoological. The -four monographs on the Cirripedia, recent and fossil, occupied eight -years--from October, 1846, to October, 1854. The works on the recent -forms were published by the Ray Society (1851 and 1854), and those on -the fossil forms by the Palæontographical Society (1851 and 1854). -These researches grew directly out of his observations on the _Beagle_, -but it is evident that they reached far greater dimensions than he had -at first intended. Thus, at the very beginning of the work, he wrote -(October, 1846) to Hooker:-- - - “I am going to begin some papers on the lower marine animals, - which will last me some months, perhaps a year, and then I shall - begin looking over my ten-year-long accumulation of notes on - species and varieties, which, with writing, I dare say will take - me five years, and then, when published, I dare say I shall stand - infinitely low in the opinion of all sound Naturalists--so this - is my prospect for the future.” - -Darwin himself, at any rate towards the end of his life, when he -wrote his “Autobiography,” doubted “whether this work was worth -the consumption of so much time,” although admitting that it was -of “considerable value” when he had “to discuss in the ‘Origin of -Species’ the principles of a natural classification.” Sir Joseph Hooker -remembers that Darwin at an earlier time “recognised three stages -in his career as a biologist: the mere collector at Cambridge; the -collector and observer in the _Beagle_ and for some years afterwards; -and the trained naturalist after, and only after, the Cirripede work” -(Letter to F. Darwin). - -Professor Huxley considers that just as by Darwin’s practical -experience of physical geography, geology, etc., on the _Beagle_, “he -knew of his own knowledge the way in which the raw materials of these -branches of science are acquired, and was, therefore, a most competent -judge of the speculative strain they would bear,” so his Cirripede work -fitted him for his subsequent speculations upon the deepest biological -problems. “It was a piece of critical self-discipline, the effect of -which manifested itself in everything your father wrote afterwards, -and saved him from endless errors of detail” (Letter to F. Darwin, -“Life and Letters”). The history of Darwin’s career has often been -used as an argument against those who, not having passed through a -similar training as regards systematic zoological work, have ventured -to concern themselves with the problems of evolution. Professor Meldola -has recently treated of this subject in his interesting presidential -address to the Entomological Society (1896). He says:-- - - “It used formerly to be asserted that he only is worthy of - attention who has done systematic, _i.e._ taxonomic, work. - I do not know whether this view is still entertained by - entomologists; if so, I feel bound to express my dissent. It - has been pointed out that the great theorisers have all done - such work--that Darwin monographed the Cirripedia, and Huxley - the oceanic Hydrozoa, and it has been said that Wallace’s and - Bates’s contributions in this field have been their biological - salvation. I yield to nobody in my recognition of the value - and importance of taxonomic work, but the possibilities of - biological investigation have developed to such an extent - since Darwin’s time that I do not think this position can any - longer be seriously maintained. It must be borne in mind that - the illustrious author of the ‘Origin of Species’ had none of - the opportunities for systematic training in biology which any - student can now avail himself of. To him the monographing of the - Cirripedia was, as Huxley states in a communication to Francis - Darwin, ‘a piece of critical self-discipline,’ and there can be - no reasonable doubt that this value of systematic work will be - generally conceded. That this kind of work gives the sole right - to speculate at the present time is, however, quite another - point.” - -Meldola then goes on to argue that the systematic work of those who -know nothing of the living state of the species they are describing -does not specially fit them for theorising, and he concludes by quoting -the following passage from a letter recently received from A. R. -Wallace:-- - - “I do not think species-describing is of any special use to the - philosophical generaliser, but I do think the collecting, naming, - and classifying some extensive group of organisms is of great - use, is, in fact, almost essential to any thorough grasp of the - whole subject of the evolution of species through variation - and natural selection. I had described nothing when I wrote my - papers on variation, etc. (except a few fishes and palms from the - Amazon), but I had collected and made out species very largely - and had seen to some extent how curiously useful and protective - their forms and colours often were, and all this was of great use - to me.” - -Towards the end of this long period of hard taxonomic labour, we know -from Darwin’s letters that he was extremely tired of the work; but -with marvellous resolution--and in spite of the trouble of his health, -which was perhaps worse than at any other time--he clung to and carried -through this stupendous task, although all the time attracted away from -it by the weightier problems which he could never thrust aside after -they had once made their claim upon him. - -[Sidenote: ON NAMING SPECIES.] - -Darwin was evidently greatly disconcerted at the task of making out -those special difficulties which man has added to the difficulties of -Nature herself--the disheartening tangle of nomenclature. He thought -that the custom of appending the name of the systematist after that of -the species or genus he had named was injurious to the interests of -science--inducing men to name quickly rather than describe accurately. -Some of his remarks on this subject indicate the state of his mind. -Thus he wrote to Hooker, October 6th, 1848:-- - - “I have lately been trying to get up an agitation ... against - the practice of Naturalists appending for perpetuity the name - of the _first_ describer to species. I look at this as a direct - premium to hasty work, to _naming_ instead of _describing_. A - species ought to have a name so well known that the addition of - the author’s name would be superfluous, and ... empty vanity.... - Botany, I fancy, has not suffered so much as zoology from mere - _naming_; the characters, fortunately, are more obscure.... Why - should Naturalists append their own names to new species, when - Mineralogists and chemists do not do so to new substances?” - -And again he wrote to Hugh Strickland, January 29th, 1849:-- - - “I have come to a fixed opinion that the plan of the first - describer’s name, being appended for perpetuity to a species, has - been the greatest curse to Natural History.... I feel sure as - long as species-mongers have their vanity tickled by seeing their - own names appended to a species, because they miserably described - it in two or three lines, we shall have the same _vast_ amount of - bad work as at present, and which is enough to dishearten any man - who is willing to work out any branch with care and time.” - -And in another letter (February 4th) to the same correspondent:-- - - “In mineralogy I have myself found there is no rage to merely - name; a person does not take up the subject without he intends - to work it out, as he knows that his _only_ claim to merit rests - on his work being ably done, and has no relation whatever to - _naming_.... I do not think more credit is due to a man for - defining a species, than to a carpenter for making a box. But I - am foolish and rabid against species-mongers, or rather against - their vanity; it is useful and necessary work which must be done; - but they act as if they had actually made the species, and it was - their own property.” - -A little later in the same year (1849) his health seems to have -determined him to give up the crusade, for he writes to Hooker (April -29th):-- - - “With health and vigour, I would not have shewn a white feather, - [and] with aid of half-a-dozen really good Naturalists, I - believe something might have been done against the miserable and - degrading passion of mere species naming.” - -Anyone whose researches have been among the species of any much-worked -and much-collected zoological group will quite agree that synonymy is, -as Darwin found it, heart-breaking work; and although there may be -good reasons why the system of appending the describer’s name must be -retained, such a protest as that raised in these letters cannot fail to -do good in drawing attention to an abuse which is only too common, and -which introduces unnecessary difficulty and gratuitous confusion into -the study of Nature. - -[Sidenote: DEATH OF HIS FATHER.] - -His father, Dr. Darwin, died November 13th, 1848, at the age of -eighty-three, when he was so much out of health that he was unable to -attend the funeral. In 1851 he lost his little daughter Annie, who died -at Malvern, April 23rd. A few days after her death he wrote a most -affecting account of her--a composition of great beauty and pathos. - - - - -CHAPTER VI. - -THE GROWTH OF THE “ORIGIN OF SPECIES” (1837–58). - - -In dealing with this subject in his “Autobiography,” Darwin tells us -of his reflections whilst on the voyage of the _Beagle_, and here -mentions another observation which deeply impressed him in addition -to those which he again repeats, on the relation between the living -and the dead in the same area and on the productions of the Galapagos -Archipelago--viz. “the manner in which closely allied animals replace -one another in proceeding southwards over the continent” (of South -America). On the theory of separate creation the existence of such -representative species received no explanation, although it became -perfectly intelligible on the theory that a single species may be -modified into distinct, although nearly related, species in the course -of its range over a wide geographical area. Here, too, the evidence -is in favour of evolution simply, and does not point to any cause of -evolution. - -He also implies that even at this time he regarded the beautiful -adaptations or contrivances of nature by which organisms are fitted -to their habits of life--“for instance, a woodpecker or a tree-frog -to climb trees, or a seed for dispersal by hooks or plumes”--as the -most striking and important phenomena of the organic world, and the -one great difficulty in the path of any naturalist who should attempt -to supply a motive force for evolution. And he regarded the previous -attempts at an explanation--the direct action of surroundings and the -will of the organism--as inadequate because they could not account for -such adaptations. - -Therefore being convinced of evolution, but as yet unprovided with a -motive cause which in any way satisfied him, he began in July, 1837, -shortly after his return home from the _Beagle_, to collect all facts -which bore upon the modifications which man has induced in the animals -and plants which he has subjugated, following, as he tells us, the -example of Lyell in geology. He goes on to say in his “Autobiography”:-- - - “I soon perceived that selection was the key-stone of man’s - success in making useful races of animals and plants. But how - selection could be applied to organisms living in a state of - nature remained for some time a mystery to me.” - -[Sidenote: COLLECTION OF NOTES.] - -We see indications in the extracts from his note-book at this period -(viz. between July, 1837, and February, 1838), and before he had -arrived at the conception of Natural Selection, that he had the idea -of “laws of change” affecting species to some extent like the laws of -change which compel the individuals of every species to work out their -own development, the extinction of the one corresponding in a measure -to the death of the other. Thus he says, “It is a wonderful fact, -horse, elephant, and mastodon dying out about the same time in such -different quarters. Will Mr. Lyell say that some [same?] circumstance -killed it over a tract from Spain to South America? Never.” We know -that a few months later he would have himself accepted the view he -imputes to Lyell, and would have regarded the extinction as due to -some circumstance affecting the competition for food or some other -relationship with the organic life of the same district. It is probable -that the above quotation from his Diary was written in connection with -the conclusion of Chapter IX. of the first edition of the “Journal of -the Voyage” (pp. 211, 212); for the latter is a fuller exposition of -the same argument.[B] - - “One is tempted to believe,” he says, “in such simple relations, - as variation of climate and food, or introduction of enemies, - or the increased numbers of other species, as the cause of the - succession of races. But it may be asked whether it is probable - that [“than” is an evident misprint in the original] any such - cause should have been in action during the same epoch over - the whole northern hemisphere, so as to destroy the _Elephas - primigenius_ on the shores of Spain, on the plains of Siberia, - and in Northern America.... These cases of extinction forcibly - recall the idea (I do not wish to draw any close analogy) of - certain fruit-trees, which, it has been asserted, though grafted - on young stems, planted in varied situations, and fertilized by - the richest manures, yet at one period have all withered away and - perished. A fixed and determined length of life has in such cases - been given to thousands and thousands of buds (or individual - germs), although produced in long succession.” - -He then concludes that the animals of one species, although “each -individual appears nearly independent of its kind,” may be bound -together by common laws. He ends by arguing that the adaptations -of animals confined to certain areas cannot be related to the -peculiarities of climate or country, because other animals introduced -by man are often so much more successful than the aborigines. As to the -causes of extinction, “all that at present can be said with certainty -is that, as with the individual, so with the species, the hour of life -has run its course, and is spent.” - -[Sidenote: EARLY VIEWS.] - -At this time he had the conception--as we see in the succeeding -extracts from his Diary--of species being so constituted that they -must give rise to other species; or, if not, that they must die out, -just as an individual dies unrepresented if it has no offspring; that -change--and evidently change in some fixed direction--or extinction, is -inevitable in the history of a species after a certain period of time. -With this view, which presented much resemblance to that of the author -of the “Vestiges,” and which seemed uppermost in his mind at this time, -there are traces of others. Thus in one extract the “wish of parents” -was thought of as a very doubtful explanation of adaptation, while in -another we meet a tolerably clear indication of natural selection, a -variety which is not well adapted being doomed to extinction, while a -favourable one is perpetuated, the death of a species being regarded as -“a consequence ... of non-adaptation of circumstances.” - -It seems certain that for fifteen months after July, 1837, he was -keenly considering the various causes of evolution which were -suggested to him by the facts of nature, and that some general idea of -natural selection presented itself to him at times, although without -any of the force and importance it assumed in his mind at a later time. - -In October, 1838, he read “Malthus on Population,” and as he says:-- - - “Being well prepared to appreciate the struggle for existence - which everywhere goes on from long-continued observation of the - habits of animals and plants, it at once struck me that under - these circumstances favourable variations would tend to be - preserved, and unfavourable ones to be destroyed. The result of - this would be the formation of new species. Here then I had a - theory by which to work.” - -[Sidenote: SKETCH OF THE “ORIGIN.”] - -In June, 1842, he wrote a brief account of the theory, occupying -thirty-five pages. In Lyell’s and Hooker’s introduction to the joint -paper by Darwin and Wallace in the Linnean Society’s Journal (1858) it -is stated that the first sketch was made in 1839, but Francis Darwin -shows (“Life and Letters,” 1887, Vol. II. pp. 11, 12) that in all -probability this is an error--a note of Darwin’s referring to the first -complete grasp of the theory after reading Malthus, being mistaken for -a reference to the first written account. - -In 1844 the sketch was enlarged to a written essay occupying 231 pages -folio--“a surprisingly complete presentation of the argument afterwards -familiar to us in the ‘Origin of Species’” published fifteen years -later. Professor Huxley, after reading this essay, observed that “much -more weight is attached to the influence of external conditions in -producing variation, and to the inheritance of acquired habits than in -the ‘Origin,’” while Professor Newton pointed out that the remarks on -the migration of birds anticipate the views of later writers.[C] - -The explanation of divergence of species during modification -(divergence of character) had not then occurred to him, and he tells us -in the “Autobiography”:-- - - “I can remember the very spot in the road, whilst in my carriage, - when to my joy the solution occurred to me; and this was long - after I had come to Down. The solution, as I believe, is that - the modified offspring of all dominant and increasing forms tend - to become adapted to many and highly diversified places in the - economy of nature.” - -A good example of this tendency is seen in the relations of three great -vertebrate classes--mammals, birds, and fishes--to the environments for -which they are respectively fitted: earth, air, and water. Competition -is most severe between forms most nearly alike, and hence some measure -of relief from competition is afforded when certain members of each of -these classes enter the domain of one of the others. Hence, we observe -that although mammals as a whole are terrestrial, a small minority -are aërial and aquatic; although birds are aërial, a minority are -terrestrial and aquatic; although fishes are aquatic, a minority tend -to be, at any rate largely, terrestrial and aërial. - -Huxley considered it “curious that so much importance should be -attached to this supplementary idea. It seems obvious that the theory -of the origin of species by natural selection necessarily involves -the divergence of the forms selected” (“Obituary,” 1888, reprinted -in “Darwiniana,” 1893; see pp. 280, 281). But Darwin showed that -divergence might be a great advantage in itself, and would then be -directly (and not merely incidentally and indirectly) encouraged and -increased by natural selection. - -[Sidenote: RESOLVE TO PUBLISH.] - -As soon as the 1844 sketch was finished, Darwin wrote a letter (July -5th) as his “solemn and last request” that his wife would, in the -case of his death, devote £400, or if necessary £500, in publishing -it, and would take trouble in promoting it. He suggests Lyell as the -best editor, then Edward Forbes, then Henslow (“quite the best in many -respects”), then Hooker (“would be _very_ good”), then Strickland. -After Strickland he had thought of Owen as “very good,” but added, -“I presume he would not undertake such a work.” If no editor could -be obtained, he requested that the essay should be published as it -was--stating that it was not intended for publication in its present -form. In August, 1854, he wrote on the back of the letter: “Hooker by -far best man to edit my Species volume.” - -All this shows how certain he felt that he was on firm ground, and that -his theory of natural selection was of vast importance to science. This -same strong conviction appears clearly in the first edition of the -“Origin,” and is undoubtedly one of the secrets of its power to move -the minds of men. Although the author is above all others fair-minded; -although he is most keen to discover and to bring forward all opposing -evidence, and to criticise most minutely everything favourable; -nevertheless, looking at the evidence as a whole, he has no doubt as -to its bearing, and feels, and shows that he feels, a magnificent -confidence in the truth and the importance of his theory. - - - - -CHAPTER VII. - -GROWTH OF THE “ORIGIN” (_continued_)--CORRESPONDENCE WITH FRIENDS. - - -The great periods of Darwin’s scientific career are marked by intimate -friendships, which must be taken into account in attempting to trace -his mental development. Henslow was his intimate friend at Cambridge -and during the voyage of the _Beagle_. The influence of Lyell, through -his writings, was of the utmost importance during the voyage, and was -deepened by the close personal contact which took place on Darwin’s -return. Sir Joseph Hooker was his most intimate friend during the -growth of the “Origin of Species.” - -Although Hooker met Darwin in 1839, their friendship did not begin -until four years later, when the former returned from the Antarctic -Expedition. On January 11th, 1844, Darwin wrote admitting his -conclusions on the question of evolution:--“At last gleams of light -have come,” he says, “and I am almost convinced (quite contrary to the -opinion I started with) that species are not (it is like confessing a -murder) immutable” (“Life and Letters,” Vol. II. p. 23). - -[Sidenote: INQUIRIES AND EXPERIMENTS.] - -From this point onwards his letters, especially to Hooker, indicate -the course he was following and the various problems he was considering -as they arose. Thus we find that he had finished reading Wollaston’s -“Insecta Maderensia” in 1855 (writing March 7th), and had been struck -with the very large proportion of wingless beetles, and had interpreted -the observation, viz. “that powers of flight would be injurious to -insects inhabiting a confined locality, and expose them to be blown -to the sea.” It is of great interest thus to witness the origin of a -theory which has since been universally accepted, and has received -confirmation from many parts of the world. - -On April 11th of the same year he is experimenting on the powers of -resistance to immersion in salt water possessed by seeds, and he -writes an account of it to Hooker. The object of these experiments was -to throw light on the means by which plants have been transported to -islands. - -In the same year began his correspondence with Asa Gray, who soon -became one of his warmest friends. He had numerous questions to ask -about the geographical range of plants, and in 1857 he wrote explaining -in some detail the views at which he had arrived as to the causes of -evolution. - -My friend Rowland H. Wedgwood, a nephew of Darwin, has given me -the following interesting letter to his father, which was written, -he believes, probably before 1855. By kind permission, it is here -published for the first time. The letter is of great interest, as -throwing light upon his work, and also because of this early reference -to Huxley:-- - - “Down, _Sept. 5_. - - “MY DEAR HARRY,--I am very much obliged for the Columbine seed - and for your note which made us laugh heartily. - - “I had no idea what trouble the counting must have been, I had - not the least conception that there would have been so many pods. - I am very much interested on this point, and therefore to make - assurance sure, I repeat your figures viz. 560 and 742 pods on - two plants and 7200 on another. Does the latter number really - mean pods and not seeds? Upon my life I am sorry to give so much - trouble, but I should be VERY MUCH obliged for a few _average_ - size pods, put up separately that I may count the seeds in each - pod: for though I counted the seeds in the pods sent before, I - hardly dare trust them without counting more. Moreover I sadly - want more seed itself for one of my experiments. - - “The young cabbages are coming up already. Thank you much about - the asparagus seeds; as it is so rare a plant, you are my only - chance. - - “We have been grieved to hear about poor Anne and Tom.--Your - affect^{te} screw - - “C. DARWIN. - - “Have you been acquainted with Mr. Huxley; I think you would find - him a pleasant acquaintance. He is a very clever man.” - -Mr. Francis Darwin believes that the asparagus and cabbage seeds were -for the experiments to determine the time during which immersion in -salt water could be endured. The object of such experiments was to -throw light on the means by which plants are distributed over the -earth’s surface. He also informs me that the use of the word “screw” is -unique and incomprehensible. - -Darwin tells us in the “Autobiography” that “early in 1856 Lyell -advised me to write out my views pretty fully, and I began at once to -do so on a scale three or four times as extensive as that which was -afterwards followed in my ‘Origin of Species.’” This work he began on -May 14th, and, after working steadily until June, 1858, had written -about half the book, in ten chapters, when he received the celebrated -letter from Wallace, which altered everything. - -[Sidenote: ON THE “ATLANTIS” THEORY.] - -At this period we get interesting evidence of his extraordinary insight -in the strong protests he makes against the Atlantis hypothesis -of Edward Forbes, and the other vast continental extensions which -naturalists did not hesitate to make in order to explain the existence -of species common to countries separated by wide tracts of the ocean. -These lost continents were as generally accepted as they were freely -proposed. And yet we find that, even then, one thinker far ahead of his -time saw clearly enough--as the _Challenger_ Expedition twenty years -later proved beyond all doubt--that the geological evidence is against -such extension, and that the means of distribution possessed by animals -are such as to render the supposition unnecessary. - -In June, 1856, he writes to Lyell: “My blood gets hot with passion and -turns cold alternately at the geological strides, which many of your -disciples are taking”; and after mentioning the extension of continents -proposed by many leading naturalists, he says: “If you do not stop -this, if there be a lower region for the punishment of geologists, I -believe, my great master, you will go there. Why, your disciples in -a slow and creeping manner beat all the old Catastrophists who ever -lived! You will live to be the great chief of the Catastrophists.” -Lyell wrote disagreeing on the subject of continental extension; and -hence, on June 25th, 1856, Darwin replied in a long letter, giving -in detail his reasons for rejecting the hypothesis. He argued (1) -that the supposed extension of continents and fusion of islands would -be vast changes, giving the earth a new aspect, but that recent and -tertiary molluscs, etc., are distinct on opposite sides of the existing -continents; so that, although he did not doubt _great_ changes of level -in parts of continents, he concluded that “_fundamentally_ they stood -as barriers to the sea where they now stand” ever since the appearance -of living species; (2) that if a continent were nearly submerged, the -last remaining peaks would by no means always be volcanic, as are, -almost without exception, the oceanic islands; (3) that the amount of -subsidence which took place in continental areas during the Silurian -and Carboniferous periods--viz. during one tolerably uniform set of -beings--would not be enough to account for the depth of the ocean over -some parts of the site of the supposed submerged continents; (4) that -the supposed extensions are not consistent with the _absence_ of many -groups of animals--_e.g._ mammals, frogs, etc.--from islands. - -These arguments did not convince Lyell; and they have only received -an almost universal acceptance after the confirmatory evidence -afforded by the voyage of the _Challenger_. Dredgings over many parts -of the ocean showed that all the continental deposits are collected -on a fringing shelf not more than 200 miles wide, and that beyond -this in the ocean bed proper an entirely different kind of deposit is -accumulating, composed of the shells, bones, and teeth of swimming or -floating organisms, or the products of their decomposition, of volcanic -and cosmic dust, and the products--_e.g._ manganese dioxide--of the -decomposition of these and of floating pumice. Hence, the depths of the -ocean afford no indications of a lost continental area, but are covered -by a peculiar deposit unknown among the rocks of continents which were -formed in comparatively shallow water round and not far from coasts, or -in land-locked or nearly land-locked seas like the Mediterranean. - -[Sidenote: EARLY CORRESPONDENCE.] - -On July 20th, 1856, he wrote to Asa Gray, giving some account of his -views, and stating his belief in evolution, but only hinting at natural -selection. - -About this time we meet with evidence of the great difficulty with -which Darwin’s ideas were thoroughly understood, even by his intimate -friends, to whom he often wrote on the subject. Later on, when the -“Origin of Species” was published, although the arguments in favour -of natural selection were given in considerable detail, many years -passed before the theory itself was understood by the great body of -naturalists. This particular case of misunderstanding is of such great -interest that it is desirable to consider it in detail. - -In the origin of new species by natural selection, the stress -of competition determines the survival of favourable individual -variations, and these, when by the continued operation of the -process they have become constant, are added to those pre-existing -characters of the species which are inherited from a remote past, -and are witnesses of the operation of natural selection from age to -age under ever-changing conditions of competition and variation. It -follows, therefore, that the origin of a species can only take place -once; for it is infinitely improbable that the same variation would -be independently submitted under the same conditions of competition, -and added to the mass of inherited characters independently gained in -two distinct lines by natural selection acting in the same manner upon -the same variations in the same order through all ages. Not only is it -inconceivable that the same species could arise by natural selection -from distinct lines of ancestry, but it is extremely improbable that -the same species could arise independently in more than one centre -among the individuals of a changing species; for in this case, too, -it is most unlikely that the same conditions of competition would -co-exist with the same favourable variations in the areas inhabited by -independent colonies of the same species. - -[Sidenote: EARLY CRITICISM.] - -Under other theories of evolution--direct action of environment, -supposed inherited effects of use and disuse, etc.--an independent -origin, even from quite distinct lines, would be probable; and we find, -accordingly, that those who would advance such theories believe in what -is called the “polyphyletic” origin of species (_e.g._ the horse), and -in the principle of “convergence” carried far enough to produce the -same complex character (_e.g._ vertebrate teeth) twice over without any -genetic connection between the forms in which the character appears. - -Under natural selection, however, such a result would be infinitely -improbable, and hence this theory strongly supports, and indeed -explains, the theory of “specific centres,” viz. that each species -has arisen in one area only, and has spread from that into the other -areas over which it now occurs. This view was strongly held by Lyell -and Hooker after an exhaustive study of the facts then known as to the -geographical distribution of plants and animals; and yet both of these -distinguished naturalists seem to have feared that Darwin, in advancing -a theory which was entirely consistent with their convictions and -utterly inconsistent with any other views upon the same subject, was in -some way undermining the conclusions at which they had arrived. - -Thus Lyell wrote (July 25th, 1856) to Hooker:-- - - “I fear much that if Darwin argues that species are phantoms, - he will also have to admit that single centres of dispersion - are phantoms also, and that would deprive me of much of the - value which I ascribe to the present provinces of animals and - plants, as illustrating modern and tertiary changes in physical - geography.” - -And on August 5th of the same year Darwin replied to Hooker, who had -apparently argued that the origin of species by direct action of -climate, etc., would mean independent and multiple specific centres:-- - - “I see from your remarks that you do not understand my notions - (whether or no worth anything) about modification; I attribute - very little to the direct action of climate, etc. I suppose, in - regard to specific centres, we are at cross purposes; I should - call the kitchen garden in which the red cabbage was produced, - or the farm in which Bakewell made the Shorthorn cattle, - the specific centre of these _species_! And surely this is - centralisation enough!” - -As I have argued above, Darwin was all the time affording the strongest -support to the theory of specific centres: support which was entirely -wanting in the theory of separate creation, in which the origin of each -species is wrapped in mystery, so that we can form no opinion as to -whether it took place at one centre or at many. - -At this time, when the views set forth in the “Origin” were gaining -shape and expression, we cannot estimate too highly the value of the -correspondence with Hooker. In after years, when the “Origin” had to -stand the fire of adverse criticism, and at first of very general -disapproval, it was of inestimable advantage that every idea contained -in it should have been minutely discussed beforehand with one who -was more critical and more learned than the greatest of those who -afterwards objected. Darwin tells us in his “Autobiography”:-- - - “I think that I can say with truth that in after years, though I - cared in the highest degree for the approbation of such men as - Lyell and Hooker, who were my friends, I did not care much about - the general public.” - -But, although Darwin cared nothing for it, it is nevertheless true that -the approbation of minds such as these was a sure indication of the -general approbation of the intellect of the country, and of the world, -which was to follow as soon as the new ideas were absorbed. - -[Sidenote: VALUE OF THE DISCUSSION.] - -And the value which Darwin himself placed on these discussions appears -again and again in his letters. To take a single example, he writes to -Hooker November 23rd, 1856:-- - - “I fear I shall weary you with letters, but do not answer this, - for in truth and without flattery, I so value your letters, - that after a heavy batch, as of late, I feel that I have been - extravagant and have drawn too much money, and shall therefore - have to stint myself on another occasion.” - - - - -CHAPTER VIII. - -DARWIN AND WALLACE (1858). - - -The history of Darwin’s friendship with Alfred Russel Wallace is of -quite unique interest, being brought about by the fact that both -naturalists saw in evolution and its causes the great questions of the -immediate future, and by the agreement in the interpretations which -they independently offered. Wallace was collecting and observing in -the Malay Archipelago, and wrote to Darwin as the one man most likely -to sympathise with and understand his views and to offer valuable -criticism. - -In the “Annals and Magazine of Natural History” for 1855, Wallace -published a paper “On the Law that has Regulated the Introduction -of New Species,” and in this and a letter written from the Malay -Archipelago Darwin recognised the similarity of their views, although -the completeness of this agreement was to be brought before him with -startling force a year after his sympathetic reply, written May 1st, -1857. He then wrote:-- - - “By your letter and even still more by your paper in the Annals, - a year or more ago, I can plainly see that we have thought much - alike and to a certain extent have come to similar conclusions. - In regard to the Paper in the Annals, I agree to the truth of - almost every word of your paper; and I dare say that you will - agree with me that it is very rare to find oneself agreeing - pretty closely with any theoretical paper; for it is lamentable - how each man draws his own different conclusions from the very - same facts.” - -On December 22nd he replied to another letter from Wallace, again -expressing agreement with all his conclusions except that upon the -supposed continental extension to oceanic islands, on which, alluding -to his previous discussion, he says:-- - - “You will be glad to hear that neither Lyell nor Hooker thought - much of my arguments. Nevertheless, for once in my life, I dare - withstand the almost preternatural sagacity of Lyell.” - -And he concludes with the wish-- - - “May all your theories succeed, except that on Oceanic Islands, - on which subject I will do battle to the death.” - -He also said, as regards Wallace’s conclusions: “I believe I go -much further than you; but it is too long a subject to enter on my -speculative notions.” - -[Sidenote: WALLACE’S ESSAY.] - -Finally, on June 18th, 1858, Darwin received from Wallace a manuscript -essay bearing the title “On the Tendency of Varieties to depart -indefinitely from the Original Type.” Upon this essay he wanted -Darwin’s opinion, and asked him, if he thought well of it, to forward -it to Lyell. Darwin was startled to find in the essay a complete -account of his own views. That very day he wrote to Lyell, enclosing -the essay. In the letter he said:-- - - “Your words have come true with a vengeance--that I should - be forestalled. You said this, when I explained to you here - very briefly my views of ‘Natural Selection’ depending on the - struggle for existence. I never saw a more striking coincidence; - if Wallace had my MS. sketch written out in 1842, he could not - have made a better short abstract! Even his terms now stand as - heads of my chapters.” - -A few days later (June 25th) he again wrote to Lyell, saying-- - - “I should be extremely glad now to publish a sketch of my general - views in about a dozen pages or so; but I cannot persuade - myself that I can do so honourably. Wallace says nothing about - publication, and I enclose his letter. But as I had not intended - to publish any sketch, can I do so honourably, because Wallace - has sent me an outline of his doctrine? I would far rather burn - my whole book, than that he or any other man should think that I - had behaved in a paltry spirit.” - -He also asked Lyell to send the letter on to Hooker, “for then I shall -have the opinion of my two best and kindest friends.” He was so much -distressed at the idea of being unfair to Wallace that he wrote again -the next day to put the case against himself in an even stronger light. -This must have been one of the most trying times in Darwin’s life, for, -in addition to the cause of trouble and perplexity described above, one -of his children died of scarlet fever, and there was the gravest fear -lest the others should be attacked. - -[Sidenote: BOTH ESSAYS PUBLISHED.] - -Thus appealed to, Lyell and Hooker took an extremely wise and fair -course. They asked Darwin for an abstract of his work, and, accepting -the whole responsibility, communicated it and Wallace’s essay in -a joint paper to the Linnean Society, giving an account of the -circumstances of the case in a preface, which took the form of a -letter to the Secretary of the Society. In this letter they introduced -to the Society “the results of the investigations of the indefatigable -naturalists, Mr. Charles Darwin and Mr. Alfred Wallace.” - - “These gentlemen having, independently and unknown to one - another, conceived the same very ingenious theory to account for - the appearance and perpetuation of varieties and of specific - forms on our planet, may both fairly claim the merit of being - original thinkers in this important line of enquiry; but neither - of them having published his views, though Mr. Darwin has for - many years past been repeatedly urged by us to do so, and both - authors having now unreservedly placed their papers in our hands, - we think it would best promote the interests of science that a - selection from them should be laid before the Linnean Society.” - -After giving a list of these selections, they say of Wallace’s essay-- - - “This was written at Ternate[D] in February, 1858, for the - perusal of his friend and correspondent Mr. Darwin, and sent - to him with the expressed wish that it should be forwarded to - Sir Charles Lyell, if Mr. Darwin thought it sufficiently novel - and interesting. So highly did Mr. Darwin appreciate the value - of the views therein set forth, that he proposed, in a letter - to Sir Charles Lyell, to obtain Mr. Wallace’s consent to allow - the Essay to be published as soon as possible. Of this step we - highly approved, provided Mr. Darwin did not withhold from the - public, as he was strongly inclined to do (in favour of Mr. - Wallace), the memoir which he had himself written on the same - subject, and which, as before stated, one of us had perused in - 1844, and the contents of which we had both of us been privy - to for many years. On representing this to Mr. Darwin, he gave - us permission to make what use we thought proper of his memoir, - &c.; and in adopting our present course, of presenting it to the - Linnean Society, we have explained to him that we are not solely - considering the relative claims to priority of himself and his - friend, but the interests of science generally; for we feel it to - be desirable that views founded on a wide deduction from facts, - and matured by years of reflection, should constitute at once a - goal from which others may start, and that, while the scientific - world is waiting for the appearance of Mr. Darwin’s complete - work, some of the leading results of his labours, as well as - those of his able correspondent, should together be laid before - the public.” - -The title of the joint paper was “On the Tendency of Species to form -Varieties; and on the Perpetuation of Varieties and Species by Natural -Means of Selection.” It was read July 1st, 1858. - - - - -CHAPTER IX. - -DARWIN’S SECTION OF THE JOINT MEMOIR READ BEFORE THE LINNEAN SOCIETY -JULY 1, 1858. - - -[Sidenote: FIRST PUBLISHED ESSAY.] - -The first section of Darwin’s communication consisted of extracts -from the Second Chapter of the First Part of his manuscript essay of -1844. The Part was entitled “The Variation of Organic Beings under -Domestication, and in their Natural State,” and the Second Chapter was -headed “On the Variation of Organic Beings in a State of Nature; on -the Natural Means of Selection; on the Comparison of Domestic Races -and True Species.” The extracts first deal with the tendency towards -rapid multiplication and the consequent struggle for life. The average -constancy of the numbers of individuals is traced to the average -constancy of the amount of food, “whereas the increase of all organisms -tends to be geometrical.” Practical illustrations are given in the -enormous increase of the mice in La Plata during the drought which -killed millions of cattle, and in the well-known and rapid increase -of the animals and plants introduced by man into a new and favourable -country. - -The checks which operate when the country is stocked and the species -reaches its average are most difficult to detect, but none the less -certain. If any check is lightened in the case of any organism it will -at once tend to increase. “Nature may be compared to a surface on which -rest ten thousand sharp wedges touching each other and driven inward by -incessant blows.” Darwin meant by this image to express that just as -any single wedge would instantly rise above the rest when the blows on -it were in any way lessened as compared with those on the other wedges, -so it would be with the proportionate number of any species when the -checks to which it is subjected are in any way relaxed. - -If the external conditions alter, and the changes continue progressing, -the inhabitants will be less well adapted than formerly. The changed -conditions would act on the reproductive system and render the -organisation plastic. Now, can it be doubted, from the struggle each -individual has to obtain subsistence, that any minute variation in -structure, habits, or instincts adapting that individual better to the -new conditions would tell upon its vigour and health? “Yearly more are -bred than can survive; the smallest grain in the balance, in the long -run, must tell on which death shall fall, and which shall survive.” If -this went on for a thousand generations who will deny its effect “when -we remember what, in a few years, Bakewell effected in cattle, and -Western in sheep, by this identical principle of selection?” - -He gives an imaginary example of a canine animal preying on rabbits and -hares. If the rabbits, constituting its chief food, gradually became -rarer, and the hares more plentiful, the animal would be driven to -try and catch more hares, and hence would be selected in the direction -of speed and sharp eyesight. “I can see no more reason to doubt that -these cases in a thousand generations would produce a marked effect, -and adapt the form of the fox or dog to the catching of hares instead -of rabbits, than that greyhounds can be improved by selection and -careful breeding.” So also with plants having seeds with rather more -down, leading to wider dissemination. Darwin here added this note: “I -can see no more difficulty in this, than in the planter improving his -varieties of the cotton plant. C. D. 1858.” - -Then follows a brief sketch of sexual selection and a comparison -with natural selection, and the conclusion is reached--“this kind -of selection, however, is less vigorous than the other; it does not -require the death of the less successful, but gives to them fewer -descendants. The struggle falls, moreover, at a time of year when food -is generally abundant, and perhaps the effect chiefly produced would -be the modification of the secondary sexual characters, which are not -related to the power of obtaining food, or to defence from enemies, but -to fighting with or rivalling other males.” - -The second section was entitled “Abstract of a Letter from C. Darwin, -Esq., to Professor Asa Gray, Boston, U.S., dated Down, September 5th, -1857.” To this letter Darwin attached great importance as a convenient -and brief account of the essentials of his theory, written and sent to -Asa Gray many months before he received Wallace’s essay. A tolerably -full abstract of the letter, which is itself a very brief abstract, -is therefore printed below. The epitome here given is taken from the -letter itself, and is in certain respects more full than that published -in the Linnean Journal. - -In the introductory parts Darwin explained that “the facts which -kept me longest scientifically orthodox are those of adaptation--the -pollen-masses in asclepias--the mistletoe, with its pollen carried by -insects, and seed by birds--the woodpecker, with its feet and tail, -beak and tongue, to climb the tree and secure insects. To talk of -climate or Lamarckian habit producing such adaptations to other organic -beings is futile. This difficulty I believe I have surmounted.” Having -then stated that the reasons which induced him to accept evolution -were “general facts in the affinities, embryology, rudimentary organs, -geological history, and geographical distribution of organic beings,” -he proceeds to give a brief account of his “notions on the means by -which Nature makes her species.” The following is an abstract of the -account he gives:-- - -[Sidenote: SUMMARY OF THE ESSAY.] - - I. The success with which selection has been applied by man in - making his breeds of domestic animals and plants: and this even - in ancient times when the selection was unconscious, viz. when - breeding was not thought of, but the most useful animals and - plants were kept and the others destroyed. “Selection acts only - by the accumulation of very slight or greater variations,” and - man in thus accumulating “_may be said_ to make the wool of one - sheep good for carpets, and another for cloth, &c.” - - II. Slight variations of all parts of the organism occur in - nature, and if a being could select with reference to the whole - structure, what changes might he not effect in the almost - unlimited time of which geology assures us. - - III. Animals increase so fast that, but for extermination, - the earth would not hold the progeny of even the slowest - breeding animal. Only a few in each generation can live; hence - the struggle for life, which has never yet been sufficiently - appreciated. “What a trifling difference must often determine - which shall survive and which perish!” Thus is supplied the - “unerring power” of “_Natural Selection_ ... which selects - exclusively for the good of each organic being.” - - IV. If a country were changing the altered conditions would tend - to cause variation, “not but what I believe most beings vary at - all times enough for selection to act on.” Extermination would - expose the remainder to “the mutual action of a different set of - inhabitants, which I believe to be more important to the life - of each being than mere climate.” In the infinite complexity - of the struggle for life “I cannot doubt that during millions - of generations individuals of a species will be born with - some slight variation profitable to some part of its economy; - such will have a better chance of surviving and propagating - this variation, which again will be slowly increased by the - accumulative action of natural selection; and the variety - thus formed will either coexist with, or more commonly will - exterminate its parent form.” Thus complex adaptations like those - of woodpecker or mistletoe may be produced. - - V. Numerous difficulties can be answered satisfactorily in time. - The supposed changes are only very gradual, and very slow, “only - a few undergoing change at any one time.” The imperfection of - the geological record accounts for deficient direct evidence of - change. - - VI. Divergence during evolution will be an advantage. “The - same spot will support more life if occupied by very diverse - forms.” Hence during the increase of species into its - offspring--varieties, or sub-species, or true species, the latter - “will try (only few will succeed) to seize on as many and as - diverse places in the economy of nature as possible,” and so - will tend to “exterminate its less well-fitted parent.” This - explains classification, in which the organic beings “always - _seem_ to branch and sub-branch like a tree from a common trunk; - the flourishing twigs destroying the less vigorous--the dead and - lost branches rudely representing extinct genera and families.” - -In a postscript he says:-- - - “This little abstract touches only the accumulative power of - natural selection, which I look at as by far the most important - element in the production of new forms. The laws governing the - incipient or primordial variation (unimportant except as the - groundwork for selection to act on, in which respect it is all - important), I shall discuss under several heads, but I can come, - as you may well believe, only to very partial and imperfect - conclusions.” - -It is, I think, of especial interest to find Darwin at this early -period arguing in a most convincing manner for the creative power -of natural selection. The selective power becomes, by accumulation, -of such paramount importance in the process, as compared with the -variations, that, although these latter are absolutely essential, man -may be said to _make_ his domestic breeds and Nature her species. The -man who argued thus had been through and had left behind the difficulty -that, even now, is often raised--that “before anything can be selected -it must be,” and therefore that selection is of small account as -compared with variation. - - - - -CHAPTER X. - -WALLACE’S SECTION OF THE JOINT MEMOIR READ BEFORE THE LINNEAN SOCIETY -JULY 1, 1858. - - -The communication by Alfred Russel Wallace was entitled “On the -Tendency of Varieties to depart indefinitely from the Original Type.” -An abstract of it is given below. - -[Sidenote: WALLACE’S ESSAY.] - -_Varieties_ produced in domesticity are more or less unstable, and -often tend to return to the parent form. This is usually thought to be -true for all varieties, and to be a strong argument for the original -and permanent distinctness of species. - -On the other hand, races forming “permanent or true varieties” are -well known, and there are generally no means of determining which is -the _variety_ and which the original _species_. The hypothesis of a -“permanent invariability of species” is satisfied by supposing that, -while such varieties cannot diverge from the species beyond a certain -fixed limit, they may return to it. - -This argument is founded on the assumption that _varieties_ in nature -are in all respects identical with those of domestic animals. The -object of the paper is to show that this is false, and “that there is -a general principle in nature which will cause many _varieties_ to -survive the parent species and to give rise to successive variations -departing further and further from the original type.” The same -principle explains the tendency of domestic animals to return to the -parent form. - -“The life of wild animals is a struggle for existence.” To procure -food and escape enemies are the primary conditions of existence, and -determine abundance and rarity, frequently seen in closely allied -species. - -“Large animals cannot be so abundant as small ones; the carnivora must -be less numerous than the herbivora,” eagles and lions than pigeons -and antelopes. Fecundity has little or nothing to do with this. The -least prolific animals would increase rapidly if unchecked. But wild -animals do not increase beyond their average; hence there must be an -immense amount of destruction. The abundance of species in individuals -bears no relation whatever to their fertility. Thus the excessively -abundant passenger pigeon of the United States lays only one or two -eggs. Its abundance is explained by the widespread supply of food -rendered available by its powers of flight. The food-supply “is almost -the sole condition requisite for ensuring the rapid increase of a -given species.” This explains why the sparrow is more abundant than -the red-breast, why aquatic species of birds are specially numerous -in individuals, why the wild cat is rarer than the rabbit. “So long -as a country remains physically unchanged, the numbers of its animal -population cannot materially increase.” If one species does so, others -must diminish. In the immense amount of destruction the weakest must -die, “while those that prolong their existence can only be the most -perfect in health and vigour--those who are best able to obtain food -regularly and to avoid their numerous enemies. It is, as we commenced -by remarking, ‘a struggle for existence,’ in which the weakest and -least perfectly organised must always succumb.” - -This tendency must apply to species as well as individuals, the best -adapted becoming abundant, the others scarce or even extinct. If we -knew the whole of the conditions and powers of a species “we might be -able even to calculate the proportionate abundance of individuals, -which is the necessary result.” - -Hence, first, _the animal population of a country is generally -stationary (due to food and other checks)_; second, _comparative -abundance or scarcity of individuals is entirely due to organisation -and resulting habits, the varying measure of success in the struggle -being balanced by a varying population in a given area_. - -Variations from type must nearly always affect habits or capacities. -Even changes of colour may promote concealment, while changes in the -limbs or any external organs would affect the mode of procuring food, -etc. “An antelope with shorter or weaker legs must necessarily suffer -more from the attacks of the feline carnivora”; the passenger pigeon -with less powerful wings could not always procure sufficient food. -Hence species thus modified would gradually diminish; but, on the other -hand, if modified in the direction of increased powers, would become -more numerous. Varieties will fall under these two classes--those -which will never rival, and those which will eventually outnumber, -the parent species. If, then, some alteration in conditions occurred -making existence more difficult to a certain species, first the less -favourable variety would suffer and become extinct, then the parent -species, while the superior variety would alone remain, “and on a -return to favourable circumstances would rapidly increase in numbers -and occupy the place of the extinct species and variety.” - -The superior _variety_ would thus replace the _species_, to which it -_could not_ return, for the latter could never compete with the former. -Hence a tendency to revert would be checked. But the superior variety, -when established, would in time give rise to new varieties, some of -which would become predominant. Hence _progression and continued -divergence_ would follow, but not invariably, for the criteria of -success or failure would vary, and would sometimes render a race -which was under other conditions the most favoured now the least so. -Variations without any effect on the life-preserving powers might also -occur. But it is contended that certain varieties must, on the average, -tend to persist longer than the parent species, while the scale on -which nature works is so vast that an average tendency must in the end -attain its full result. - -Comparing domestic with wild animals, the very existence of the latter -depends upon their senses and physical powers. Not so with the former, -which are defended and fed by man. - -Any favourable variety of a domestic animal is utterly useless to -itself; while any increase of the powers and faculties of wild animals -is immediately available, creating, as it were, a new and superior -animal. - -Again, with domestic animals all variations have an equal chance, and -those which would be extremely injurious in a wild state are, under the -artificial conditions, no disadvantage. Our domestic breeds could never -have come into existence in a wild state, and if turned wild “_must_ -return to something near the type of the original wild stock, _or -become altogether extinct_.”[E] - -Hence we cannot argue from domestic to wild animals, the conditions of -life in the two being completely opposed. - -Lamarck’s hypothesis of change produced by the attempts of animals to -increase the development of their own organs has been often refuted, -but the view here proposed depends upon the action of principles -constantly working in nature. Retractile talons of falcons and cats -have not been developed by volition, but by _the survival of those -which had the greatest facilities for seizing prey_. The long neck of -the giraffe was not produced by constant stretching, but by the success -which any increase in the length of neck ensured to its possessors. -Even colours, especially of insects, are explained in the same way, -for among the varieties of many tints, those “having colours best -adapted to concealment ... would inevitably survive the longest.” We -can similarly explain deficiency of some organs with compensating -development of others, “great velocity making up for the absence of -defensive weapons,” etc. Varieties with an unbalanced deficiency could -not long survive. The action of the principle is like the governor -of a steam-engine, checking irregularities almost before they become -evident. Such a view accords well with “the many lines of divergence -from a central type”; the increasing efficiency of a particular organ -in a series of allied species; the persistence of unimportant parts -when important ones have changed; the “more specialised structure,” -said by Owen to be characteristic of recent as compared with extinct -forms. - -Hence there is a tendency of certain classes of _varieties_ to progress -further and further from the original type, and there is no reason for -assigning any limit to this progression. Such gradual changes “may, -it is believed, be followed out so as to agree with all the phenomena -presented by organised beings, their extinction and succession in past -ages, and all the extraordinary modifications of form, instinct, and -habits which they exhibit.” - -Wallace’s Essay has been reprinted without any alteration in his -“Essays on Natural Selection,” recently re-issued combined with -“Tropical Nature.” - - - - -CHAPTER XI. - -COMPARISON OF DARWIN’S AND WALLACE’S SECTIONS OF THE JOINT -MEMOIR--RECEPTION OF THEIR VIEWS--THEIR FRIENDSHIP. - - -[Sidenote: WALLACE AND DARWIN.] - -Comparing the essays of these two naturalists, we observe that Darwin -here first makes public the phrase “natural selection,” Wallace the -“struggle for existence”; although so closely do their lines of thought -converge that Darwin, using practically the same words, speaks of -the “struggle for life.” Both show, by examples, the tendency of all -animals to multiply at an enormous rate, and both show that their -tolerably constant numbers are due to the constant supply of food. - -Both treat of domesticated animals, but in very different ways. Darwin -uses them as the practical illustration of selection, and argues that -if man by selection can make such forms, Nature can make her species -by the same means. Wallace disposes of the argument that the reversion -of domesticated varieties to the wild form is a proof of the permanent -distinctness of species, by showing in some detail that the former are -“abnormal, irregular, artificial.” - -Neither of them draws any distinction between instinct and other -qualities, but assumes that the former is, like the latter, operated -upon by natural selection. - -Wallace makes a special point of protective resemblances in the colours -of insects, etc. - -The important principle of “divergence of character,” and the -relatively unimportant one of “sexual selection,” are both clearly -explained by Darwin. - -Neither writer speaks of the direct effect of external -conditions--except as a cause of plasticity by Darwin--or the inherited -effects of use and disuse. Lamarck is mentioned only to be dismissed -by Wallace. The evolution of the giraffe’s long neck is explained by -Wallace on the principle of natural selection, which is contrasted with -Lamarck’s original explanation of the same character. This contrast, -which has been so often drawn, was therefore originally contained in -the first public statement of natural selection. - -As has been indicated above, Darwin suggested a cause of variation in -the direct effect of changed external conditions on the reproductive -system. - -In comparing the two essays it is not unnatural to conclude, as -Professor Osborn has done (“From the Greeks to Darwin,” 1894, p. -245), that the two writers held different views upon the material -utilised by natural selection in the production of new species, Darwin -relying upon the usual slight differences which separate individuals -and upon variations in single characters, Wallace upon fully formed -varieties--viz. individuals which departed conspicuously from the type -of the species, and which may exist singly or in considerable numbers -side by side with the parent form. - -Professor Osborn’s actual words are as follows:-- - - “Darwin dwells upon _variations in single characters_, as taken - hold of by Selection; Wallace mentions variations, but dwells - upon _full-formed varieties_, as favourably or unfavourably - adapted. It is perfectly clear that with Darwin the struggle is - so intense that the chance of survival of each individual turns - upon a single and even slight variation. With Wallace, varieties - are already presupposed by causes which he does not discuss, - a change in the environment occurs, and those varieties which - happen to be adapted to it survive. There is really a wide gap - between these two statements and applications of the theory.” - -Further consideration tends to obliterate this supposed distinction. -Although Wallace used the term “variety” as contrasted with “species,” -the whole context proves that he, equally with Darwin, recognised -the importance of individual variations and of variations in single -characters. This becomes clear when we remember his argument about the -neck of the giraffe, the changes of colour and hairiness, the shorter -legs of the antelope, and the less powerful wings of the passenger -pigeon. Wallace has kindly written to me (May 12th, 1896) stating the -case as I have given it, and he further explains-- - - “I used the term ‘varieties’ because ‘varieties’ were alone - recognised at that time, individ^l variability being ignored or - thought of _no importance_. My ‘varieties’ therefore included - ‘individual variations.’” - -On the other hand, Darwin certainly included large single variations -(in other words, “varieties”) as well as ordinary individual -differences, among the material for natural selection, and he did not -abandon the former until he was convinced by the powerful reasoning of -Fleeming Jenkin (_North British Review_, June, 1867), who argued that -single large differences of a sudden and conspicuous kind (Darwin’s -“variations”) would certainly be swamped by intercrossing. Upon this -review of the “Origin” Francis Darwin says (“Life and Letters”)-- - - “It is not a little remarkable that the criticisms which my - father, as I believe, felt to be the most valuable ever made on - his views should have come, not from a professed naturalist but - from a Professor of Engineering.” - -After reading this review, Darwin wrote to Wallace (January 22nd, -1869):-- - - “I always thought individual differences more important than - single variations, but now I have come to the conclusion that - they are of paramount importance, and in this I believe I agree - with you. Fleeming Jenkin’s arguments have convinced me.” - -The ambiguity of this sentence evidently misled Wallace into believing -that the single variations were considered of paramount importance. -Darwin therefore wrote again (February 2nd):-- - - “I must have expressed myself atrociously; I meant to say exactly - the reverse of what you have understood. F. Jenkin argued in the - ‘North British Review’ (June 1867) against single variations - ever being perpetuated, and has convinced me, though not in - quite so broad a manner as here put. I always thought individual - differences more important; but I was blind and thought single - variations might be preserved much oftener than I now see is - possible or probable. I mentioned this in my former note merely - because I believed that you had come to a similar conclusion, - and I like much to be in accord with you. I believe I was mainly - deceived by single variations offering such simple illustrations, - as when man selects.” - -From these two letters to Wallace we see that the latter was the first -to give up the larger variations in favour of ordinary individual -differences. - -Darwin also wrote to Victor Carus on May 4th, 1869:-- - - “I have been led to ... infer that single variations are even of - less importance, in comparison with individual differences, than - I formerly thought.” - -There has been much misconception on this point, and a theory of -evolution by the selection of large single variations--a view held by -many, but not by Darwin--has been passed off as the Darwinian theory of -natural selection. It is surprising that this old mistake should have -been repeated at so recent a date, and on so important an occasion as -the Presidential Address to the British Association at Oxford on August -8th, 1894, and that so ill-aimed a criticism should have been quoted -with approval in a leading article in the _Times_ of the following day. -The following extracts from Lord Salisbury’s address unfortunately -leave no doubt on the matter: - -[Sidenote: LORD SALISBURY’S CRITICISM.] - - “What is to secure that the two individuals of opposite sexes - in the primeval forest, who have been both accidentally blessed - with the same advantageous variation shall meet, and transmit by - inheritance that variation to their successors?... The biologists - do well to ask for an immeasurable expanse of time, if the - occasional meetings of advantageously varied couples from age to - age are to provide the pedigree of modifications which unite us - to our ancestor the jelly-fish.... There would be nothing but - mere chance to secure that the advantageously varied bridegroom - at one end of the wood should meet the bride, who by a happy - contingency had been advantageously varied in the same direction - at the same time at the other end of the wood. It would be a - mere chance if they ever knew of each other’s existence--a still - more unlikely chance that they should resist on both sides all - temptations to a less advantageous alliance. But unless they did - so, the new breed would never even begin, let alone the question - of its perpetuation after it had begun.” - -It is of interest to reproduce Lord Salisbury’s words in close -proximity to Darwin’s real statements on the subject, as shown in the -letters to his friends--statements which are also expressed in many -places in his published works. - -The joint paper was read before the Linnean Society on July 1st, 1858, -about a fortnight after Wallace’s essay had been received by Darwin. -There was no discussion, but the interest and excitement at the meeting -were very great, owing in large part to the influential support -with which the new theory came before the scientific world. Darwin -appreciated the importance of this support at its true value, for he -wrote to Hooker, July 5th:-- - - “You must know that I look at it, as very important, for the - reception of the view of species not being immutable, the fact of - the greatest Geologist and Botanist in England taking _any sort - of interest_ in the subject: I am sure it will do much to break - down prejudices.” - -In the following January Darwin received a letter from Wallace, and -his reply (on the 25th) shows how much relieved and pleased he was -at its generous spirit. Alluding to Lyell’s and Hooker’s action in -his “Autobiography” Darwin says:--“I was at first very unwilling -to consent, as I thought Mr. Wallace might consider my doing so -unjustifiable, for I did not then know how generous and noble was his -disposition.” It was this letter which conveyed the knowledge to him -and set his mind at rest on the subject. - -Thus ended one of the most interesting and memorable episodes in the -history of science. It was sufficiently remarkable that two naturalists -in widely-separated lands should have independently arrived at the -theory which was to be the turning-point in the history of biology -and of many other sciences--although such simultaneous discoveries -have been known before; it was still more remarkable that one of the -two should unknowingly have chosen the other to advise him upon the -theory which was to be for ever associated with both their names. -It was a magnificent answer to those who believed that the progress -of scientific discovery implies continual jealousy and bitterness, -that the conditions attending the first publication of the theory of -natural selection were the beginning of a life-long friendship and of -mutual confidence and esteem.[F] - -[Sidenote: FRIENDSHIP WITH WALLACE.] - -It is justifiable to speak of this episode as the _beginning_ of -Darwin’s and Wallace’s friendship, for the latter writes (February, -1895):-- - - “I had met him _once_ only for a few minutes at the Brit. Mus. - before I went to the East.” - -Later on Darwin, in his letters to Wallace, more than once alluded to -the simultaneous publication of their essays. Thus he wrote, April -18th, 1869, congratulating Wallace on his article in the _Quarterly -Review_ for that month:-- - - “I was also much pleased at your discussing the difference - between our views and Lamarck’s. One sometimes sees the odious - expression, ‘Justice to myself compels me to say,’ &c., but you - are the only man I ever heard of who persistently does himself an - injustice, and never demands justice. Indeed, you ought in the - review to have alluded to your paper in the ‘Linnean Journal,’ - and I feel sure all our friends will agree in this. But you - cannot ‘Burke’ yourself however much you may try, as may be seen - in half the articles which appear.” - -And again, on April 20th of the following year, he wrote:-- - - “I hope it is a satisfaction to you to reflect--and very few - things in my life have been more satisfactory to me--that we have - never felt any jealousy towards each other, though in one sense - rivals. I believe that I can say this of myself with truth, and I - am absolutely sure that it is true of you.” - - - - -CHAPTER XII. - -THE GROWTH OF WALLACE’S CONVICTIONS ON EVOLUTION AND DISCOVERY OF -NATURAL SELECTION--BORNEO 1855--TERNATE 1858. - - -We have already seen in the earlier part of this volume, the gradual -development of the theory of Natural Selection in the mind of Darwin, -and the long succession of experiments and observations which he -undertook before he could bring himself to publish anything upon the -subject, as well as the conditions which forced him to a hurried -publication in the end. It is of the deepest interest to compare with -this the account which Wallace has given us of the mental process by -which he arrived at the same conclusions. - -This deeply interesting personal history has only been known during -the last few years; in 1891 Wallace republished his “Essays on Natural -Selection” in one volume, combined with “Tropical Nature,” and he has -added (on pp. 20, 21) the following introductory note to Chapter II., -viz. the reprint of his Linnean Society Memoir “On the Tendencies of -Varieties to depart indefinitely from the Original Type.” The note is -here reprinted in full:-- - - “As this chapter sets forth the main features of a theory - identical with that discovered by Mr. Darwin many years before - but not then published, and as it has thus an historical - interest, a few words of personal statement may be permissible. - After writing the preceding paper [“On the Law which has - Regulated the Introduction of New Species”] the question of - _how_ changes of species could have been brought about was - rarely out of my mind, but no satisfactory conclusion was - reached till February 1858. At that time I was suffering from - a rather severe attack of intermittent fever at Ternate in the - Moluccas, and one day, while lying on my bed during the cold - fit, wrapped in blankets, though the thermometer was at 88° - Fahr., the problem again presented itself to me, and something - led me to think of the ‘positive checks’ described by Malthus - in his ‘Essay on Population,’ a work I had read several years - before, and which had made a deep and permanent impression on my - mind. These checks--war, disease, famine and the like--must, it - occurred to me, act on animals as well as man. Then I thought of - the enormously rapid multiplication of animals, causing these - checks to be much more effective in them than in the case of - man; and while pondering vaguely on this fact there suddenly - flashed upon me the _idea_ of the survival of the fittest--that - the individuals removed by these checks must be on the whole - inferior to those that survived. In the two hours that elapsed - before my ague fit was over I had thought out almost the whole - of the theory, and the same evening I sketched the draft of my - paper, and in the two succeeding evenings wrote it out in full, - and sent it by the next post to Mr. Darwin. Up to this time - the only letters I had received from him were those printed in - the second volume of his _Life and Letters_ (vol. ii., pp. 95 - and 108), in which he speaks of its being the twentieth year - since he ‘opened his first note-book on the question how and - what way do species and varieties differ from each other,’ and - after referring to oceanic islands, the means of distribution - of land-shells, &c., added: ‘My work, on which I have now been - at work more or less for twenty years, _will not fix or settle - anything_; but I hope it will aid by giving a large collection - of facts, with one definite end.’ The words I have italicised, - and the whole tone of his letters, led me to conclude that he - had arrived at no definite view as to the origin of species, - and I fully anticipated that my theory would be new to him, - because it seemed to me to settle a great deal. The immediate - result of my paper was that Darwin was induced at once to - prepare for publication his book on the _Origin of Species_ in - the condensed form in which it appeared, instead of waiting an - indefinite number of years to complete a work on a much larger - scale which he had partly written, but which in all probability - would not have carried conviction to so many persons in so short - a time. I feel much satisfaction in having thus aided in bringing - about the publication of this celebrated book, and with the - ample recognition by Darwin himself of my independent discovery - of ‘natural selection.’ (See _Origin of Species_, 6th ed., - introduction, p. 1, and Life and Letters, vol. ii, chap. iv., pp. - 115–129 and 145).” - -[Sidenote: ORIGIN OF WALLACE’S ESSAY.] - -A very similar account, differing in a few unimportant details from -that quoted above, was written December 3rd, 1887, by Wallace to -Professor Newton, and is published in the abridged “Life and Letters of -Charles Darwin” (1892; pp. 189, 190). At the conclusion Wallace says:-- - - “... I _had_ the idea of working it out, so far as I was able, - when I returned home, not at all expecting that Darwin had so - long anticipated me. I can truly say _now_, as I said many years - ago, that I am glad it was so; for I have not the love of _work_, - _experiment_ and _detail_ that was so pre-eminent in Darwin, and - without which anything I could have written would never have - convinced the world.” - -It is of great interest to learn that Wallace as well as Darwin was -directed to natural selection by Malthus’ Essay. Hence, as the late -Professor Milnes Marshall has pointed out (Lectures on the Darwinian -Theory, pp. 212, 213), the laws of the multiplication and extinction -of man suggested to both naturalists those more general laws by which -it was possible to understand the development of the whole animal and -vegetable worlds. - -There is a tremendous contrast between these two discoverers, in -the speed with which they respectively developed their ideas on the -subject into a shape which satisfied them as suitable for publication. -Wallace, after the inspiration which followed his reflections upon -Malthus, had “thought out almost the whole of the theory” in two hours, -and in three evenings had completed his essay. Darwin, receiving the -same inspiration from the same source, in October 1838, wrote a brief -account of it after four years’ reflection and work, and finished a -longer account two years later, but was not prepared to give anything -to the public until he was compelled to do so fourteen years later -in 1858. All this delay was of the greatest advantage when a full -exposition of the theory finally came before the world in the “Origin -of Species”; for all difficulties had been fully considered and -answered beforehand, while the wealth of new facts by which it was -supported compelled a respectful hearing for the theory itself. - -[Sidenote: WALLACE’S VIEWS.] - -Wallace, like Darwin, was convinced of evolution before he discovered -any principle which supplied a motive cause for the process. This -conviction is expressed very clearly in his interesting essay already -alluded to “On the Law which has regulated the Introduction of New -Species” (Ann. and Mag., Nat. Hist., 1855, p. 184; reprinted without -alteration in his Essays on Natural Selection). The law he states in -these words:-- - - “Every species has come into existence coincident both in time - and space with a pre-existing closely allied species,” - -a law which, as he justly claims for it, - - “connects together and renders intelligible a vast number of - independent and hitherto unexplained facts. The natural system of - arrangement of organic beings, their geographical distribution, - their geological sequence, the phenomena of representative and - substituted groups in all their modifications, and the most - singular peculiarities of anatomical structure, are all explained - and illustrated by it, in perfect accordance with the vast mass - of facts which the researches of modern naturalists have brought - together, and, it is believed, not materially opposed to any of - them. It also claims a superiority over previous hypotheses, on - the ground that it not merely explains, but necessitates what - exists. Granted the law, and many of the most important facts in - Nature could not have been otherwise, but are almost as necessary - deductions from it, as are the elliptic orbits of the planets - from the law of gravitation.” - -This important essay is dated by Wallace from Sarawak, Borneo, -February, 1855. - -The conclusions remind us of the words Darwin wrote in his note-book in -1837. “Led to comprehend true affinities. My theory would give zest to -recent and Fossil comparative Anatomy.” By his theory Darwin here means -evolution and not natural selection, which was not discovered by him -until the end of 1838. - - - - -CHAPTER XIII. - -CANON TRISTRAM THE FIRST PUBLICLY TO ACCEPT THE THEORY OF NATURAL -SELECTION (1859). - - -Although the historic meeting at the Linnean Society appeared to -produce but little effect, one distinguished naturalist publicly -accepted the theory of natural selection before the publication of “The -Origin of Species,” and therefore as the direct result of Darwin’s -and Wallace’s joint paper. This great distinction belongs to Canon -Tristram, as Professor Newton has pointed out in his Presidential -Address to the Biological Section of the British Association at -Manchester in 1887 (“Reports,” p. 727), at the same time expressing the -hope “that thereby the study of Ornithology may be said to have been -lifted above its fellows.” - -[Sidenote: CANON TRISTRAM’S SUPPORT.] - -Canon Tristram’s paper, “On the Ornithology of Northern Africa” (Part -iii., The Sahara, continued), was published in _The Ibis_, vol. i., -October, 1859. The important conclusions alluded to above are contained -at the end of the section upon the species of desert larks (pp. -429–433): - - “Writing with a series of about 100 larks of various species from - the Sahara before me, I cannot help feeling convinced of the - truth of the views set forth by Messrs. Darwin and Wallace in - their communications to the Linnean Society, to which my friend - Mr. A. Newton last year directed my attention.... It is hardly - possible, I should think, to illustrate this theory better than - by the larks and chats of North Africa. In all these birds we - trace gradual modifications of coloration and of anatomical - structure, deflecting by very gentle gradations from the ordinary - type; but when we take the extremes, presenting most marked - differences.” - -These differences, he concludes-- - - “have a very direct bearing on the ease or difficulty with which - the animal contrives to maintain its existence.” - -He then points out, upon the uniform surface of the desert it is -absolutely necessary that animals shall be protected by their colour: - - “Hence, without exception, the upper plumage of every bird, - whether Lark, Chat, Sylvian, or Sandgrouse, and also the fur - of all the small mammals, and the skin of all the Snakes and - Lizards, is of one uniform isabelline or sand colour. It is - very possible that some further purpose may be served by the - prevailing colours, but this appears of itself a sufficient - explanation. There are individual varieties in depth of hue among - all creatures. In the struggle for life which we know to be going - on among all species, a very slight change for the better, such - as improved means of escaping from its natural enemies (which - would be the effect of an alteration from a conspicuous colour - to one resembling the hue of the surrounding objects), would - give the variety that possessed it a decided advantage over the - typical or other forms of the species. Now in all creatures, - from Man downwards, we find a tendency to transmit individual - varieties or peculiarities to the descendants. A peculiarity - either of colour or form soon becomes hereditary when there - are no counteracting causes, either from change of climate or - admixture of other blood. Suppose this transmitted peculiarity - to continue for some generations, especially when manifest - advantages arise from its possession, and the variety becomes not - only a race, with its variations still more strongly imprinted - upon it, but it becomes the typical form of that country.” - -Canon Tristram then points out the manner in which he imagines that one -of the crested larks of the desert has been produced by the survival -of the lightest coloured individuals, _Galerida abyssinica_ only -differing in this respect from _G. cristata_ of Europe. Short-billed -species of the same genus inhabiting hard rocky districts, and -long-billed inhabiting loose sandy tracts have, he believes, been -produced by the survival in each case of the forms of bill most suited -to procure food: - - “Here are only two causes enumerated which might serve to - _create_ as it were a new species from an old one, yet they - are perfectly natural causes, and such as, I think, must have - occurred, and are possibly occurring still. We know so very - little of the causes which in the majority of cases make - species rare or common, that there may be hundreds of others - at work, some even more powerful than these, which go to - perpetuate and eliminate certain forms ‘according to natural - means of selection.’ But even these superficial causes appear - sufficient to explain the marked features of the Desert races, - which frequently approach so very closely the typical form, and - yet possess such invariably distinctive characteristics, that - naturalists seem agreed to elevate them to the rank of species.” - -Although the author also declares his belief in the special creation -of many species--a view put forward as possible by Darwin in the -“Origin”[G]--and also believed in some direct influence of locality, -climate, etc., the above quoted passages are a most complete acceptance -of natural selection, at the same time affording excellent examples of -its operation. - - - - -CHAPTER XIV. - -THE PREPARATION OF “THE ORIGIN OF SPECIES” (1858–59). - - -Almost immediately after the Linnean Society meeting, and evidently -earlier than September, the time mentioned in his “Autobiography,” -Darwin began to prepare a longer and more complete account of his work -on evolution and natural selection. This account was at first intended -for the Linnean Society, but it was soon found to be too long, and he -then decided to publish it as an independent volume. In thus preparing -the manuscript for what afterwards became the “Origin of Species,” -Darwin tells us (“Autobiography”) he acted under “the strong advice of -Lyell and Hooker,” and his letters also show the great interest that -they were taking in the work. - -Darwin seems to have found the “Origin”--or his “Abstract,” as he -always calls it--very hard work, and he ends his letter to Wallace -(January 25th, 1859) with the words: - - “I look at my own career as nearly run out. If I can publish my - Abstract and perhaps my greater work on the same subject, I shall - look at my course as done.” - -At the same time, so great was his enthusiasm and interest, in spite -of the hard work and ill-health, that all through this period he was -making fresh observations whenever an opportunity occurred. Thus we -find him writing to Hooker about the thistle-down blown out to sea and -then back to shore again; about the migrations of slave-making ants -which he had been watching; about the bending of the pistil into the -line of the gangway leading to the honey when this latter “is secreted -at one point of the circle of the corolla,” etc. And on March 2nd, -1859, he writes about “an odd, though very little, fact”:--Large nuts -had been found in the crops of some nestling Petrels at St. Kilda, -which he suspected the parent birds had picked up from the Gulf Stream. -He arranged for one of these to be sent, and asked Hooker for the name -and country. He asks forgiveness for the trouble, “for it is a funny -little fact after my own heart.” The nuts turned out to be West Indian. - -When the proposal for publication had been accepted by Murray and the -manuscript was assuming its final form, the letters to Hooker were more -frequent than ever. Writing on May 11th, 1859, Darwin again raises the -question of the relative importance of variation and selection. - - “I imagine from some expressions ... that you look at variability - as some necessary contingency with organisms, and further that - there is some necessary tendency in the variability to go on - diverging in character or degree. _If you do_, I do not agree.” - -Darwin’s splendid confidence in the future appears in a letter written -about this time (September 2, 1859) in which he begs Lyell not to -commit himself “to go a certain length and no further; for,” he says, -“I am deeply convinced that it is absolutely necessary to go the whole -vast length, or stick to the creation of each separate species.” He -asks Lyell to remember that his verdict will probably be of more -importance than the book itself in influencing the present acceptance -or rejection of the views. “In the future,” he continues, “I cannot -doubt about their admittance, and our posterity will marvel as much -about the current belief as we do about fossil shells having been -thought to have been created as we now see them.” And again writing -to Lyell a few days later (September 20th), he says, “I cannot too -strongly express my conviction of the general truth of my doctrines, -and God knows I have never shirked a difficulty.” - -I have thought it well to bring strong evidence of Darwin’s entire -confidence in his conclusions, because his writings were so -extraordinarily balanced and judicial, and the weight he gives to -opposing considerations so great, that a superficial student might -imagine that he wrote and argued without any very strong convictions. - -The letters to Mr. John Murray, the publisher, are eminently -characteristic, in the expressions of regret for trouble given, and -of pleasure at the work done, in the scrupulous care to prevent the -publisher from feeling committed, if on further acquaintance with the -manuscript he did not wish to accept it, and in the offer to contribute -towards the cost of corrections. - -[Sidenote: THE “ORIGIN” PUBLISHED.] - -The first edition of “The Origin of Species” was published November -24th, 1859. The edition consisted of 1,250 copies, all of which were -sold on the day of issue. - -The full title of this volume, of which Darwin justly says -(“Autobiography”), “It is no doubt the chief work of my life,” is -reproduced below. - - ON - - THE ORIGIN OF SPECIES - - BY MEANS OF NATURAL SELECTION, - - OR THE - - PRESERVATION OF FAVOURED RACES IN THE STRUGGLE - FOR LIFE. - - BY CHARLES DARWIN, M.A., - - FELLOW OF THE ROYAL, GEOLOGICAL, LINNEAN, ETC., SOCIETIES; - AUTHOR OF “JOURNAL OF RESEARCHES DURING H.M.S. ‘BEAGLE’S’ VOYAGE - ROUND THE WORLD.” - -This title is of interest, as has been pointed out by Professor E. Ray -Lankester, in relation to the controversy upon the exact meaning of the -word “Darwinism.” Some writers have argued that the term “Darwinism” -includes the whole of the causes of evolution accepted by Darwin--the -supposed inherited effects of use and disuse and the direct influence -of environment, which find a subordinate place in the “Origin,” as -well as natural selection, which is the real subject of the book and -which is fully defined in the title. It would seem appropriate to -use the term “Darwinism,” as Wallace uses it, to indicate the causes -of evolution which were suggested by Darwin himself, excluding these -supposed causes which had been previously brought forward by earlier -writers, and especially by Lamarck. The causes of evolution proposed -by Lamarck are seriously disputed, and it is possible that they may -be ultimately abandoned. If so, the integrity of “Darwinism,” as -interpreted by some controversialists, would be impaired; and this, it -will be generally admitted, would be most unfortunate, as well as most -unfair to the memory of Darwin. - - - - -CHAPTER XV. - -THE ORIGIN OF SPECIES (1859). - - -[Sidenote: THE ORIGIN OF SPECIES.] - -It is very interesting to separate the two arguments which occur -interwoven in the “Origin”--the argument for evolution and the -argument for natural selection. The paramount importance of Darwin’s -contributions to the evidences of organic evolution are often forgotten -in the brilliant theory which he believed to supply the motive cause -of descent with modification. Organic evolution had been held to be -true by certain thinkers during many centuries; but not only were -its adherents entirely without a sufficient motive cause, but their -evidences of the process itself were erroneous or extremely scanty. -It was Darwin who first brought together a great body of scientific -evidence which placed the process of evolution beyond dispute, whatever -the causes of evolution may have been. And accordingly we find that, -even at first, natural selection was attacked far more generally than -the doctrine of descent with modification. - -In Chapter I., Variation under Domestication and man’s power of -selection in forming breeds of animals and plants are discussed; in -Chapter II., Variation under Nature; in Chapter III., the Struggle for -Existence; in Chapter IV., which Darwin, in writing to his publisher, -called “the Keystone of my Arch,” the three preceding chapters are -carried to their conclusion, and the operation of natural selection -is explained and discussed. Hence, these four chapters deal almost -exclusively with this process. - -Chapter V. has for its subject the Laws of Variation, and explains -causes of modification (external conditions, use and disuse, -correlation, reversion, etc.) other than natural selection and the -relation of the latter to the former. - -In Chapter VI. difficulties are considered--partly those in the way -of a belief in evolution and partly those which, at first sight, seem -to be incapable of explanation on the theory of natural selection. -Chapter VII. deals with a special difficulty of the latter kind, viz. -Instinct, and shows how it can be accounted for by natural selection -acting upon variation, although allowing some weight to the inheritance -of habit. Chapter VIII. deals with Hybridism, the sterility of first -crosses and of hybrids being considered as an objection to the doctrine -of Descent with Modification. Chapter IX. treats of the Imperfection -of the Geological Record as the explanation of the apparently -insufficient evidence of evolution during past ages. Chapter X., on the -Geological succession of Organic Beings, shows that, allowing for this -Imperfection of Record, the facts brought to light by Geology support a -belief in evolution and in some cases even in natural selection. Hence -these five chapters deal partly with difficulties in the way of an -acceptance of organic evolution and partly with those encountered by -natural selection. - -Of the three remaining chapters before the XIVth, and last, which -contains the Recapitulation and Conclusion, two--XI. and XII.--are -concerned with Geographical distribution, while the XIIIth deals with -Classification, Morphology, Embryology and Rudimentary Organs. These -three chapters are almost entirely devoted to the proof that the facts -of Nature with which they deal are not inconsistent with, but rather -support, and often strongly support, a belief in Organic Evolution. - -Hence we see that this, incomparably the greatest work which the -biological sciences have seen, begins with an explanation and defence -and definition of the sphere of natural selection--then passes to -consider difficulties which are partly those of natural selection, and -partly of organic evolution--while it finally treats of the evidences -of the latter process and the difficulties which a belief in it -encounters. - -This arrangement was a very wise one for a book which was intended to -convince a large circle of readers; for the human mind so craves after -an explanation, that it was of more importance for the success of the -work to show first that an intelligible cause of evolution had been -proposed, than to follow the more logical order of first setting forth -the evidences of evolution. - -The second edition (fifth thousand) was issued in January, 1860, the -third (seventh thousand) in 1861, the fourth (eighth thousand) in 1866, -the fifth (tenth thousand) in 1869, the sixth in 1872: in 1887 the -twenty-fourth thousand was reached. - -A note to the last edition states that the second “was little more -than a reprint of the first. The third edition was largely corrected -and added to, and the fourth and fifth still more largely.” The sixth -edition also contains “numerous small corrections,” and is about -one-fourth larger than the first edition, although this material is, -owing to the smaller print and more crowded lines, compressed into a -smaller number of pages. The sixth edition also differs from the first -in containing a glossary, an historical sketch, and a note and list of -the chief corrections. - -The titles of Chapters I., II., and III. remain the same in the first -and last editions. Herbert Spencer’s phrase is added to Darwin’s -term, as the heading of Chapter IV., which accordingly becomes in the -last edition “Natural Selection; or the Survival of the Fittest.” -This change was certainly introduced in order to help readers to -grasp the meaning of Darwin’s title, which had been very generally -misunderstood. The heading of Chapter V. remains the same, while in -Chapter VI.--“Difficulties on Theory”--“on” is replaced by “of the.” -This chapter is, in the last edition, succeeded by a new one dealing -with many of the difficulties which had been raised or had occurred -to Darwin in the interval between the two editions; it is headed -“Miscellaneous Objections to the Theory of Natural Selection.” The -titles of the remaining eight chapters are unchanged. - -The first part of the title of the first edition--“On the Origin of -Species”--becomes “The Origin of Species” in the last edition, and is -still further shortened to “Origin of Species” on the outside of the -volume. - -The form of the earlier editions was admirably suited for the purpose -of attracting, and--so far as was possible with so difficult a -subject--convincing, a large number of readers. When the subject -was new and strange, the more numerous details of the last edition, -and the smaller print which became necessary, would have acted as a -hindrance to the complete success of the work. Authors and publishers -are sometimes apt to forget that the form of a book has a great deal to -do with the absorption of the ideas contained in it, especially when -the argument is from the nature of the case difficult to follow, and -the subject a new one. Francis Darwin in the “Life and Letters” justly -condemns the unattractive form of the sixth edition of the work. - - - - -CHAPTER XVI. - -THE INFLUENCE OF DARWIN UPON LYELL (1859–64). - - -In considering the reception of the “Origin of Species,” it will -be well first to show its effect upon Darwin’s intimate scientific -friends, most of whom had been familiar with his work for many years, -and then to deal with its effects upon biologists generally, especially -those of Darwin’s own country. - -The gradual strengthening of Darwin’s influence over his old teacher -Lyell, is one of the most interesting episodes in the personal history -of the scientific men of this century. - -[Sidenote: LYELL’S SLOW CONVERSION.] - -Lyell, after reading the proof-sheets of the “Origin,” wrote on -October 3rd, 1859, praising the work very warmly, and suggesting a few -improvements, some of which were adopted. Lyell hesitated to accept -the theory, because he saw clearly that it would be impossible to stop -short at the human species, while a common origin of men and beasts was -distasteful to him. Thus, he said:-- - - “I have long seen most clearly that if any concession is made, - all that you claim in your concluding pages will follow. It is - this which has made me so long hesitate, always feeling that - the case of man and his races, and of other animals, and that - of plants is one and the same, and that if a ‘vera causa’ be - admitted for one, instead of a purely unknown and imaginary one, - such as the word ‘Creation,’ all the consequences must follow.” - -To this letter Darwin replied (October 11th) at great length, in a most -instructive letter, arguing in considerable detail on all the points -alluded to by Lyell. He evidently thought that Lyell’s opinion was of -the utmost importance for the success of Natural Selection. “If ever -you are [perverted],” he wrote at the end of the letter, “I shall know -that the theory of Natural Selection is, in the main, safe.” - -About this time Darwin seems to have heard that Lyell had made up his -mind to admit the doctrine of evolution into a new edition of the -“Manual,” and he wrote (November 23rd):-- - - “I honour you most sincerely. To have maintained in the position - of a master, one side of a question for thirty years, and then - deliberately give it up, is a fact to which I much doubt whether - the records of science offer a parallel.” - -Lyell’s public confession of faith was, however, not to be made for -some years, and Darwin’s letter was a little premature. - -Space will not permit me to quote from the long correspondence -with Lyell in the years following the appearance of the “Origin,” -although these letters are of the deepest interest, and deal in the -most luminous manner with the difficulties of natural selection and -evolution, as they appeared to one of the acutest intellects of that -time. The letters soon began to produce an effect, and Darwin wrote -(September 26th, 1860) to Asa Gray:-- - - “I can perceive in my immense correspondence with Lyell, who - objected to much at first, that he has, perhaps unconsciously to - himself, converted himself very much during the last six months, - and I think this is the case even with Hooker. This fact gives me - far more confidence than any other fact.” - -Later on Darwin evidently became a little annoyed that Lyell still -delayed to declare his belief one way or the other. Thus he wrote to -Asa Gray (May 11th, 1863):-- - - “You speak of Lyell as a judge; now what I complain of is that - he declines to be a judge.... I have sometimes almost wished - that Lyell had pronounced against me. When I say ‘me,’ I only - mean _change of species by descent_. That seems to me the - turning-point. Personally, of course, I care much about Natural - Selection; but that seems to me utterly unimportant, compared to - the question of Creation _or_ Modification.” - -Shortly before this date, on February 24th, he wrote to Hooker in -much the same style. These communications were called forth by the -appearance of “The Antiquity of Man,” and it is clear that Darwin’s -disappointment at Lyell’s suspended judgment was due to their -correspondence, which had encouraged him to expect some definite -opinion on the question. “From all my communications with him, I must -ever think that he has really entirely lost faith in the immortality -of species,” he wrote in his letter to Hooker. On March 6th he wrote -to Lyell himself, expressing his disappointment, and again a few days -later, rather complaining that his work was treated as a modification -of Lamarck’s:-- - - “This way of putting the case ... closely connects Wallace’s and - my views with what I consider, after two deliberate readings, as - a wretched book, and one from which (I well remember my surprise) - I gained nothing.” - -When the second edition of “The Antiquity of Man” appeared in a few -months, there was a significant change in one sentence:-- - - “Yet we ought by no means to undervalue the importance of the - step which will have been made, should it hereafter become - the generally received opinion of men of science (as I fully - expect it will) that the past changes of the organic world have - been brought about by the subordinate agency of such causes as - Variation and Natural Selection.” - -The words in parentheses had been added, and constituted Lyell’s first -public expression of an opinion in favour of Darwin’s views. - -About this time an article appeared in the _Athenæum_ (March 28th, -1863), attacking the opinions in favour of evolution contained in -Dr. Carpenter’s work on Foraminifera, and supporting spontaneous -generation. This was one of the rare occasions on which Darwin entered -into controversy, and he wrote attacking spontaneous generation, and -pointing out the numerous classes of facts which are connected by -an intelligible thread of reasoning by means of his theory. In this -letter he quoted the altered sentence from the second edition of the -“Antiquity.” Darwin’s letter was answered in an article (May 2nd) in -which it was argued that _any_ theory of descent would connect the -various classes of facts equally well. To this Darwin replied in a -characteristic letter. It was evident that he was most reluctant to -continue the controversy, but thought it fair to admit publicly the -force of his opponent’s arguments. - -[Sidenote: ACCESSION OF LYELL.] - -In 1864 the Copley Medal of the Royal Society was given to Darwin. At -the anniversary dinner of the Society, after the meeting at which the -medals are presented by the President, Sir Charles Lyell in his speech -made a “confession of faith” as to the “Origin.” Darwin was prevented -by illness from receiving the medal in person and from being present at -the dinner. - -The tenth edition of the “Principles” was published in 1867 and 1868, -and in it Lyell clearly stated his belief in evolution. Sir Joseph -Hooker, in his presidential address to the British Association at -Norwich in 1868, eloquently spoke of the “new foundation” with which -Lyell had under-pinned the edifice he had raised, and had thus rendered -it “not only more secure, but more harmonious in its proportion than -it was before.” Wallace, too, in an article in the _Quarterly Review_ -(April, 1869), spoke with equal eloquence and force of the significance -of Lyell’s change of opinion. - -Lyell’s death took place in 1875, eleven years after his definite -acceptance of Darwin’s views. Darwin, in writing to Miss Arabella -Buckley (now Mrs. Fisher, formerly secretary to Sir Charles Lyell), -fully acknowledged the deep debt which he owed to Lyell’s teachings: -“I never forget that almost everything which I have done in science -I owe to the study of his great works.” Huxley says in his obituary -of Charles Darwin (reprinted in “Darwiniana,” 1893, p. 268): “It is -hardly too much to say that Darwin’s greatest work is the outcome of -the unflinching application to Biology of the leading idea and the -method applied in the ‘Principles’ to Geology.” Every biologist who -realises--as who can help realising?--the boundless opportunities which -Darwin’s work has opened for him, will feel that he too owes a deep -personal debt to Darwin’s great teacher. - - - - -CHAPTER XVII. - -INFLUENCE OF DARWIN UPON HOOKER AND ASA GRAY--NATURAL SELECTION AND -DESIGN IN NATURE (1860–68). - - -Hooker wrote on November 21st, speaking of the “glorious book” in the -warmest terms. Later on in the year he wrote again in the same spirit, -but speaking of the difficulty he found in assimilating the immense -mass of details: “It is the very hardest book to read, to full profits, -that I ever tried--it is so cram-full of matter and reasoning.” Hooker -must, however, have been familiar with the arguments and proofs, -and for this reason did not attempt any detailed discussion. It is -unnecessary to say more of Hooker’s reception of the “Origin.” During -their long friendship Darwin had discussed the difficulties and the -evidences of his theory more fully with him than with any other man; -and, as “a man sharpeneth the countenance of his friend,” the influence -of Hooker was one of the most potent forces under which Darwin produced -the greatest work of his life. - -Many years later, when Hooker was awarded, in 1887, the Copley Medal -of the Royal Society, reviewing his past experiences and work in his -speech at the anniversary dinner, he concluded by telling us that his -long and intimate friendship with Charles Darwin was the great event of -his scientific career. - -[Sidenote: ASA GRAY.] - -In sending a copy to Asa Gray, he wrote (November 11th):-- - - “I fully admit that there are very many difficulties not - satisfactorily explained by my theory of descent with - modification, but I cannot possibly believe that a false theory - would explain so many classes of facts as I think it certainly - does explain. On these grounds I drop my anchor, and believe that - the difficulties will slowly disappear.” - -Asa Gray’s reply was contained in a letter to Hooker, written January -5th, 1860, four days after reading the “Origin.” He asks that Darwin -may be told of what he had written. He says that the book “is done in -a _masterly manner_. It might well have taken twenty years to produce -it.” He expressed the intention of reviewing the book, and seeing that -Darwin and Hooker had fair play in America. A little later (January -23rd) he wrote to Darwin about the American reprint, etc., and spoke of -the work itself in somewhat greater detail:-- - - “The _best part_, I think, is the _whole_, _i.e._ its _plan_ - and _treatment_, the vast amount of facts and acute inferences - handled as if you had a perfect mastery of them.... Then your - candour is worth everything to your cause. It is refreshing to - find a person with a new theory who frankly confesses that he - finds difficulties.... The moment I understood your premisses, - I felt sure you had a real foundation to hold on.... I am free - to say that I never learnt so much from one book as I have from - yours.” - -He considered that the attempt to account for the formation of organs -such as eyes by natural selection, was the weakest point in the book. -This view is to be explained by his strong teleological convictions. - -Although Asa Gray was the great exponent of the “Origin” in America, -he could not agree with Darwin on one important point--viz. on the -exclusion of the ordinary conceptions of design in nature by the -principle of natural selection. He believed that the two conceptions -could be reconciled, and that design in some way worked in and through -natural selection. By design is here meant what Huxley called “the -commoner and coarser form of teleology,” and which he believed to be -now refuted--“the teleology which supposes that the eye, such as we see -it in man or one of the higher vertebrata, was made with the precise -structure it exhibits for the purpose of enabling the animal which -possesses it to see, has undoubtedly received its death-blow.” Huxley -goes on to point out that there is a “wider teleology, which ... is -actually based upon the fundamental proposition of evolution ... that -the whole world ... is the result of the mutual interaction, according -to definite laws, of the forces possessed by the molecules of which -the primitive nebulosity of the universe was composed.” Therefore, -“a sufficient intelligence could, from a knowledge of the properties -of the molecules of that vapour, have predicted, say, the state of -the fauna of Britain in 1869, with as much certainty as one can say -what will happen to the vapour of the breath on a cold winter’s day.” -(“Genealogy of Animals,” _The Academy_, 1869, reprinted in “Critiques -and Addresses,” and quoted in his chapter “On the Reception of the -‘Origin of Species’” in the “Life and Letters,” Vol. II.) - -But at the time of the appearance of the “Origin,” many who sympathised -with the general drift of the argument were not yet prepared for -the “wider teleology.” Of these Asa Gray may be taken as the -representative; and it will be of interest to follow the controversy -between him and Darwin as regards design and natural selection. The -recently published “Letters of Asa Gray to Charles Darwin” (Macmillan) -enable us to follow the correspondence from the side of the great -American evolutionist. - -Writing November 26th, 1860, Darwin refers to one of Asa Gray’s -articles on the “Origin”:-- - - “I grieve to say that I cannot honestly go as far as you do - about Design. I am conscious that I am in an utterly hopeless - muddle. I cannot think that the world, as we see it, is the - result of chance; and yet I cannot look at each separate thing - as the result of Design. To take a crucial example, you lead me - to infer--that you believe ‘that variation has been led along - certain beneficial lines.’ I cannot believe this; and I think - you would have to believe, that the tail of the Fantail was led - to vary in the number and direction of its feathers in order to - gratify the caprice of a few men. Yet if the Fantail had been a - wild bird, and had used its abnormal tail for some special end, - as to sail before the wind, unlike other birds, everyone would - have said, ‘What a beautiful and designed adaptation.’ Again, I - say I am, and shall ever remain, in a hopeless muddle.” - -Elsewhere Darwin suggested that the pouter pigeon, if it occurred -wild, and used its inflated crop as a float, would be considered as a -striking example of design. - -This controversy between them continued for many years. We find Asa -Gray referring to the argument of the pigeons three years later. Thus -he wrote (September 1st, 1863):-- - - “I will consider about fantastic variation of pigeons. I see afar - trouble enough ahead quoad design in nature, but have managed to - keep off the chilliness by giving the knotty questions a rather - wide berth. If I rather avoid, I cannot ignore the difficulties - ahead. But if I adopt your view boldly, can you promise me any - less difficulties?” - -Writing the concluding paragraphs of the “Variations of Animals -and Plants under Domestication,” Darwin evidently bore in mind his -controversies on the subject with Asa Gray and Lyell, and the attacks -of the Duke of Argyll and others. Sending advanced sheets to Asa Gray, -he wrote on October 16th, 1867:-- - - “I finish my book with a semi-theological paragraph, in which I - quote and differ from you; what you will think of it, I know not.” - -In relation to this interesting controversy, I think it well to quote, -almost in full, the metaphor by which Darwin enforced his argument that -the origin of species by natural selection precluded a belief in design -in nature as it was ordinarily conceived at the time. - -This metaphor forms an important part of the conclusion of the work in -question (“Variation of Animals and Plants,” etc.): - - “The long-continued accumulation of beneficial variations will - infallibly have led to structures as diversified, as beautifully - adapted for various purposes and as excellently co-ordinated, as - we see in the animals and plants around us. Hence I have spoken - of selection as the paramount power, whether applied by man to - the formation of domestic breeds, or by nature to the production - of species. I may recur to the metaphor given in a former - chapter: if an architect were to rear a noble and commodious - edifice, without the use of cut stone, by selecting from the - fragments at the base of a precipice wedged-formed stones for his - arches, elongated stones for his lintels, and flat stones for his - roof, we should admire his skill and regard him as the paramount - power. Now, the fragments of stone, though indispensable to the - architect, bear to the edifice built by him the same relation - which the fluctuating variations of organic beings bear to the - varied and admirable structures ultimately acquired by their - modified descendants. - - “Some authors have declared that natural selection explains - nothing, unless the precise cause of each slight individual - difference be made clear. If it were explained to a savage - utterly ignorant of the art of building, how the edifice had been - raised stone upon stone, and why wedge-formed fragments were used - for the arches, flat stones for the roof, &c.; and if the use of - each part and of the whole building were pointed out, it would - be unreasonable if he declared that nothing had been made clear - to him, because the precise cause of the shape of each fragment - could not be told. But this is a nearly parallel case with the - objection that selection explains nothing, because we know not - the cause of each individual difference in the structure of each - being.” - - * * * * * - - “The shape of the fragments of stone at the base of our precipice - may be called accidental, but this is not strictly correct; for - the shape of each depends on a long sequence of events, all - obeying natural laws.... But in regard to the use to which the - fragments may be put, their shape may be strictly said to be - accidental....” - -In his article in the _Nation_ (March 19th, 1868), Asa Gray criticised -the metaphor as follows:-- - - “But in Mr. Darwin’s parallel, to meet the case of nature - according to his own view of it, not only the fragments of rock - (answering to variation) should fall, but the edifice (answering - to natural selection) should rise, irrespective of will or - choice!” - -This passage is quoted in the “Life and Letters” (Vol. III., p. 84), -and Francis Darwin makes the convincing reply:-- - - “But my father’s parallel demands that natural selection shall be - the architect, not the edifice--the question of design only comes - in with regard to the form of the building materials.” - -Darwin’s reply was contained in his letter to Asa Gray dated May 8th, -1868:-- - - “You give a good slap at my concluding metaphor: undoubtedly I - ought to have brought in and contrasted natural and artificial - selection; but it seemed so obvious to me that natural selection - depended on contingencies even more complex than those which - must have determined the shape of each fragment at the base - of my precipice. What I wanted to show was that, in reference - to pre-ordainment, whatever holds good in the formation of an - English pouter-pigeon holds good in the formation of a natural - species of pigeon. I cannot see that this is false. If the right - variations occurred, and no others, natural selection would be - superfluous.” - -To this, Asa Gray replied in his letter of May 25th:-- - - “As to close of my article, to match close of your book,--you - see plainly I was put on the defence by your reference to an - old hazardous remark of mine. I found your stone-house argument - unanswerable in substance (for the notion of design must after - all rest mostly on faith, and on accumulation of adaptations, - &c.); so all I could do was to find a vulnerable spot in the - shaping of it, fire my little shot, and run away in the smoke. - - “Of course I understand your argument perfectly, and feel the - might of it.” - -From this last letter I think we may conclude that Asa Gray’s -feelings on this subject rested, as he says, “on faith,” and that, -intellectually, he saw no way of meeting Darwin’s arguments. - - - - -CHAPTER XVIII. - -INFLUENCE OF DARWIN UPON HUXLEY. - - -[Sidenote: HUXLEY AND NATURAL SELECTION.] - -It is of the utmost interest to trace the influence of Darwin upon -Huxley, his great General in the numerous controversial battles which -had to be fought before the new views were to secure a fair hearing -and, at length, complete success. Now that we are quietly enjoying the -fruit of his many victories, we are apt to forget how much we owe to -Huxley, not only for evolution, but for that perfect freedom in the -expression of thought and opinion which we enjoy. For Huxley fought -on wider issues than those raised by evolution, wide as these are; -and with a success so great that it is inconceivable that any new and -equally illuminating thought which the future may hold in store for -us, will meet with a reception like that accorded to the “Origin of -Species.” - -At first sight it seems a simple matter to describe the effect of the -“Origin” upon Huxley, considering that he, more than any other man, -expounded it, and defended it from the most weighty of the attacks made -upon it. Hence, it is only natural to believe, as many have done, that -he was in entire agreement with the conclusions of the book as regards -natural selection as well as evolution. On the other hand, the opinion -has often been expressed that Huxley, although agreeing with the -“Origin” for some years after its first appearance, changed his mind in -later years, and no longer supported Darwin’s views. - -I shall give reasons for rejecting both these opinions about Huxley, -although the first is far nearer the truth than the second. The -latter is clearly untenable, and was probably merely an inference -from the fact that after a time Huxley ceased to enter into Darwinian -controversies. But this was because he had done his work with entire -success, and therefore turned his attention in other directions. -Whenever he was called on to write or speak about Darwinism, as he was -on two occasions within a few months of his death, his writings and -speeches left no doubt about his thoughts on the subject. Furthermore, -in the Preface to “Darwiniana,” written in 1893, he expressly denied -that he had recanted or changed his opinions about Darwin’s views. - -In order to appreciate the influence of Darwin upon Huxley, we must -find out the beliefs of the latter upon the “species question” before -the appearance of the “Origin.” In his chapter “On the Reception of -the ‘Origin of Species’” (“Life and Letters,” Vol. II.) Huxley says -that, before 1858, he took up an agnostic position as regards evolution -“... upon two grounds: firstly, that up to that time, the evidence in -favour of transmutation was wholly insufficient; and, secondly, that no -suggestion respecting the causes of the transmutation assumed, which -had been made, was in any way adequate to explain the phenomena.” It -is obvious that these two grounds are entirely distinct, and that the -logical foundation of the first is far more secure than that of the -second. - -The effect of the “Origin” was completely to convince Huxley on the -first ground: from that time he never doubted the truth of evolution, -however it may have been brought about. With regard to the second -ground, it is quite clear that Huxley had a very high opinion of -natural selection: he thought it incomparably the best suggestion upon -the subject that had ever been made, and he firmly believed that it -accounted for something--that it may even have taken a dominant part -in bringing about evolution. On the other hand, he never felt quite -confident about the entire sufficiency of the evidence in its favour. -It is probable that he was far more interested in the establishment -of evolution as a fact than in natural selection as an explanation of -it. He saw the vast amount of research in all kinds of new or almost -neglected lines, which would be directly inspired by evolution. And his -own investigations in some of these lines soon afforded some of the -most weighty evidence in favour of the doctrine. Natural selection had -not the same personal interest for him; no one has expounded it better -or defended it more vigorously and successfully, but Huxley’s own -researches never lay in directions which would have made them available -as a test of the theory. Of natural selection he might have used the -words of Mercutio--it may not be “so deep as a well, nor so wide as a -church door,” to contain the whole explanation of evolution, “but ’tis -enough ’twill serve”; it will, at any rate, prevent him from feeling -the second ground on which he had maintained an agnostic position. - -I believe that he maintained these views with inflexible consistency -throughout his life, the only indications of change being in the last -year, when the contrast between his certainty of evolution and his -uncertainty of natural selection, as expressed in the two speeches -quoted on pp. 140, 141, was, perhaps, more sharply marked than at any -other period. - -It is now proposed to support this conclusion by many extracts from -Huxley’s writings, as well as from his speeches, which have been -alluded to above. The deep interest of the subject, and the wide -differences of opinion with regard to it, justify, and indeed demand, -copious quotations selected from works and speeches, written and spoken -at many different times during the years between 1858 and 1894. - -It may not be out of place to emphasise the fact that the sole -responsibility for the conclusions here drawn rests with the author of -this volume, and that the evidence on which the conclusions rest is -supplied in full. - -About a month before the “Origin” was published, Darwin wrote to -Professor Huxley asking for the names of foreigners to whom to send his -book. This communication is of great interest as being the earliest -letter, accessible to the public, which he wrote to Huxley. In it he -says: “I shall be _intensely_ curious to hear what effect the book -produces on you”; but he evidently thought that Huxley would disagree -with much in it, and must have been surprised as well as gratified at -the way in which it was received. In his chapter “On the Reception of -the ‘Origin of Species’” (“Life and Letters,” Vol. II.), Huxley writes: -“My reflection, when I first made myself master of the central idea of -the ‘Origin,’ was, ‘How extremely stupid not to have thought of that.’” - -Huxley replied on November 23rd, 1859--the day before the publication -of the “Origin”--saying that he had finished the book on the previous -day. His letter was a complete acceptance of evolution as apart from -any theory which may account for it; and a thorough agreement with -natural selection as a “true cause for the production of species.” -At no time in his life did he state how far he considered natural -selection to be a sufficient cause. He was only “prepared to go to the -stake, if requisite, in support of” the chapters which marshal the -evidence for evolution (ix., and most parts of x., xi., and xii.). - -With regard to the earlier chapters, which propound the theory of -natural selection, his exact words are:-- - - “As to the first four chapters, I agree thoroughly and fully - with all the principles laid down in them. I think you have - demonstrated a true cause for the production of species, and have - thrown the _onus probandi_, that species did not arise in the way - you suppose, on your adversaries.” - -Darwin replied with much warmth, and expressed himself as “Now -contented and able to sing my _Nunc Dimittis_.” - -In the _Times_ of December 26th, 1859, appeared a masterly article upon -the “Origin,” and, after a time, it became known that Huxley was its -author. Volume II. of the “Life and Letters” explains the circumstances -under which the review was written. The article is reprinted as the -first essay (“The Darwinian Hypothesis,” I.) in “Darwiniana” (Vol. -II. of the “Collected Essays of Professor Huxley,” London, 1893). The -following quotation (pp. 19, 20) shows the attitude he took up with -regard to natural selection:-- - - “That this most ingenious hypothesis enables us to give a reason - for many apparent anomalies in the distribution of living - beings in time and space, and that it is not contradicted by - the main phenomena of life and organisation appear to us to be - unquestionable; and, so far, it must be admitted to have an - immense advantage over any of its predecessors. But it is quite - another matter to affirm absolutely either the truth or falsehood - of Mr. Darwin’s views at the present stage of the enquiry. Goethe - has an excellent aphorism defining that state of mind which he - calls “Thätige Skepsis”--active doubt. It is doubt which so loves - truth that it neither dares rest in doubting, nor extinguish - itself by unjustified belief; and we commend this state of mind - to students of species, with respect to Mr. Darwin’s or any other - hypothesis as to their origin. The combined investigations of - another twenty years may, perhaps, enable naturalists to say - whether the modifying causes and the selective power, which Mr. - Darwin has satisfactorily shewn to exist in Nature, are competent - to produce all the effects he ascribes to them; or whether, - on the other hand, he has been led to over-estimate the value - of the principle of natural selection, as greatly as Lamarck - over-estimated his _vera causa_ of modification by exercise.” - -Of all the statements about natural selection made by Huxley, this one -seems to me the nearest to the spirit of the two speeches he made in -1894, in which it became evident that the intervening thirty-five years -had not brought the increased confidence he had hoped for. Furthermore, -in the Preface to “Darwiniana” (1893) he expressly stated that he had -not changed his mind as regards this article and the next which will be -considered (see p. 137, where the passage is quoted). - -In 1860 Huxley wrote the article on “The Origin of Species” which -appeared in the _Westminster Review_ for April, and is reprinted in -“Darwiniana.” He here states the reasons for his doubts about natural -selection in considerable detail. At the beginning of the essay -(“Darwiniana,” p. 23) he asserts that-- - - “... all competent naturalists and physiologists, whatever their - opinions as to the ultimate fate of the doctrines put forth, - acknowledge that the work in which they are embodied is a solid - contribution to knowledge and inaugurates a new epoch in natural - history.” - -Towards the end of the essay, after vindicating the logical method -followed by Darwin, he continues (pp. 73–75):-- - - “There is no fault to be found with Mr. Darwin’s method, then; - but it is another question whether he has fulfilled all the - conditions imposed by that method. Is it satisfactorily proved, - in fact, that species may be originated by selection? that - there is such a thing as natural selection? that none of the - phœnomena exhibited by species are inconsistent with the origin - of species in this way? If these questions can be answered - in the affirmative, Mr. Darwin’s view steps out of the ranks - of hypotheses into those of proved theories; but, so long as - the evidence at present adduced falls short of enforcing that - affirmation, so long, to our minds, must the new doctrine be - content to remain among the former--an extremely valuable, and - in the highest degree probable, doctrine, indeed the only extant - hypothesis which is worth anything in a scientific point of view; - but still a hypothesis, and not yet the theory of species. - - “After much consideration, and with assuredly no bias against Mr. - Darwin’s views, it is our clear conviction that, as the evidence - stands, it is not absolutely proven that a group of animals, - having all the characters exhibited by species in Nature, has - ever been originated by selection, whether artificial or natural. - Groups having the morphological character of species, distinct - and permanent races in fact, have been so produced over and - over again; but there is no positive evidence, at present, that - any group of animals has, by variation and selective breeding, - given rise to another group which was even in the least degree - infertile with the first. Mr. Darwin is perfectly aware of this - weak point, and brings forward a multitude of ingenious and - important arguments to diminish the force of the objection. We - admit the value of these arguments to their fullest extent; nay, - we will go so far as to express our belief that experiments, - conducted by a skilful physiologist, would very probably obtain - the desired production of mutually more or less infertile breeds - from a common stock, in a comparatively few years; but still, as - the case stands at present, this ‘little rift within the lute’ is - not to be disguised nor overlooked.” - -He concludes with a summary of the results of his argument. The -sentences which bear on the present question are as follows (pp. 77, -78):-- - - “Our object has been attained if we have given an intelligible, - however brief, account of the established facts connected with - species, and of the relation of the explanation of those facts - offered by Mr. Darwin to the theoretical views held by his - predecessors and his contemporaries, and, above all, to the - requirements of scientific logic. We have ventured to point - out that it does not, as yet, satisfy all those requirements; - but we do not hesitate to assert that it was superior to - any preceding or contemporary hypothesis, in the extent of - observational and experimental basis on which it rests, in its - rigorously scientific method, and in its power of explaining - biological phenomena, as was the hypothesis of Copernicus to the - speculations of Ptolemy. But the planetary orbits turned out to - be not quite circular after all, and, grand as was the service - Copernicus rendered to science, Kepler and Newton had to come - after him. What if the orbit of Darwinism should be a little - too circular? what if species should offer residual phenomena, - here and there, not explicable by natural selection? Twenty - years hence naturalists may be in a position to say whether this - is, or is not, the case; but in either event they will owe the - author of ‘The Origin of Species’ an immense debt of gratitude. - We should leave a very wrong impression on the reader’s mind if - we permitted him to suppose that the value of that work depends - wholly on the ultimate justification of the theoretical views - which it contains. On the contrary, if they were disproved - to-morrow, the book would still be the best of its kind--the - most compendious statements of well-sifted facts bearing on the - doctrine of species that has ever appeared.” - -It is clear that two very distinct points are urged in this criticism -of natural selection--(1) the difficulty that selective methods -applied by man have not as yet produced all the characteristics of -true species; (2) supposing the latter difficulty to be surmounted or -sufficiently explained, the uncertainty as to how much or how little of -the process of evolution has been due to natural selection. - -Later in the same year Darwin seems to have been a little disappointed -that Huxley’s confidence did not increase. Thus, he wrote on December -2nd, 1860:-- - - “I entirely agree with you that the difficulties on my notions - are terrific; yet having seen what all the _Reviews_ have said - against me, I have far more confidence in the _general_ truth - of the doctrine than I formerly had. Another thing gives me - confidence--viz. that some who went half an inch with me now go - further, and some who were bitterly opposed are now less bitterly - opposed. And this makes me feel a little disappointed that you - are not inclined to think the general view in some slight degree - more probable than you did at first. This I consider rather - ominous. Otherwise I should be more contented with your degree - of belief. I can pretty plainly see that if my view is ever to - be generally adopted, it will be by young men growing up and - replacing the old workers, and then young ones finding that they - can group facts and search out new lines of investigation better - on the notion of descent than on that of creation.” - -In 1863 Huxley delivered a course of lectures to working men on “The -Causes of the Phenomena of Organic Nature”; here, too, he expressed -his opinions about natural selection with great clearness and force. -These lectures are reprinted as the concluding part of “Darwiniana,” -and the references are to the pages of that volume of his collected -essays. - -On page 464 we read-- - - “Here are the phenomena of Hybridism staring you in the face, and - you cannot say, ‘I can, by selective modification, produce these - same results.’ Now, it is admitted on all hands, at present, so - far as experiments have gone, it has not been found possible - to produce this complete physiological divergence by selective - breeding.... If we were shewn that this must be the necessary and - inevitable results of all experiments, I hold that Mr. Darwin’s - hypothesis would be utterly shattered.” - -He then goes on to show that this is very far from proved, and -concludes (page 466)-- - - “that though Mr. Darwin’s hypothesis does not completely - extricate us from this difficulty at present, we have not the - least right to say it will not do so.” - -A passage on page 467 shows that Huxley placed natural selection -infinitely higher than any other attempt to account for evolution, and -indeed that he regarded all other attempts with scorn. - - “I really believe that the alternative is either Darwinism or - nothing, for I do not know of any rational conception or theory - of the Organic universe which has any scientific position at all - beside Mr. Darwin’s.... Whatever may be the objections to his - views, certainly all other theories are absolutely out of court.” - -On page 468 he continues-- - - “But you must recollect that when I say I think it is either Mr. - Darwin’s hypothesis or nothing; that either we must take his - view, or look upon the whole of organic nature as an enigma, the - meaning of which is wholly hidden from us; you must understand - that I mean that I accept it provisionally, in exactly the same - way as I accept any other hypothesis.” - -He concludes the lectures and the volume in which they are now -reproduced by the following eloquent testimony to the unique value of -the “Origin of Species”:-- - - “I believe that if you strip it of its theoretical part it still - remains one of the greatest encyclopædias of biological doctrine - that any one man ever brought forth, and I believe that, if you - take it as the embodiment of an hypothesis, it is destined to be - the guide of biological and psychological speculation for the - next three or four generations.” - -The next essay from which I quote was written in 1871. At the beginning -of “Mr. Darwin’s Critics” (“Darwiniana,” p. 120) he uses words which, -if they stood alone, might be interpreted as an indication of a -stronger conviction. - - “Whatever may be thought or said about Mr. Darwin’s doctrines, or - the manner in which he has propounded them, this much is certain, - that, in a dozen years, the ‘Origin of Species’ has worked as - complete a revolution in biological science as the ‘Principia’ - did in astronomy--and it has done so, because, in the words of - Helmholtz, it contains an ‘essentially new creative thought.’” - -This last quotation, and the following one, from “Evolution in -Biology,” written in 1878, are, I think, among the strongest -utterances in favour of natural selection to be found in the Collected -Essays. At the conclusion of the above-named essay (_l. c._, p. 223) he -states that it was clearly seen that-- - - “if the explanation would apply to species, it would not - only solve the problem of their evolution, but that it would - account for the facts of teleology, as well as for those of - morphology;...” - - “How far ‘natural selection’ suffices for the production of - species remains to be seen. Few can doubt that, if not the whole - cause, it is a very important factor in that operation; and that - it must play a great part in the sorting out of varieties into - those which are transitory and those which are permanent.” - -The seventh essay, “The Coming of Age of ‘The Origin of Species,’” was -written in 1880. His complete confidence in evolution, as shown in this -essay, may be contrasted with his cautious statements about natural -selection. He boldly affirms evolution to be the fundamental doctrine -of the “Origin of Species,” while natural selection is, I believe, -neither mentioned nor even alluded to. On this great occasion he thus -emphasised the immense debt we owe to Darwin in that he was the first -to produce adequate evidence in favour of the ancient doctrine of -evolution, a benefit quite distinct from that which he conferred in the -theory of natural selection (see pp. 100–102). - -The following are among the most confident statements about evolution -to be found in this essay. Speaking of the “Origin,” he says (p. -229):-- - - “... the general doctrine of evolution, to one side of which it - gives expression, obtains, in the phenomena of biology, a firm - base of operations whence it may conduct its conquest of the - whole realm of nature.” - -And again, on page 332:-- - - “The fundamental doctrine of the ‘Origin of Species,’ as of all - forms of the theory of evolution applied to biology, is ‘that - the innumerable species, genera, and families of organic beings - with which the world is peopled have all descended, each within - its own class or group, from common parents, and have all been - modified in the course of descent.’” - -Furthermore, on page 242 we read:-- - - “I venture to repeat what I have said before, that so far as the - animal world is concerned, evolution is no longer a speculation, - but a statement of historical fact. It takes its place alongside - of those accepted truths which must be reckoned with by - philosophers of all schools.” - -And on the same page he quotes with approval the statement by M. -Filhol of the results to which he had been led by his palæontological -investigations:-- - - “Under the influence of natural conditions of which we have no - exact knowledge, though traces of them are discoverable, species - have been modified in a thousand ways: species have arisen which, - becoming fixed, have thus produced a corresponding number of - secondary species.” - -Similarly, in the Obituary notice in _Nature_ (1882), Huxley speaks -of the secure position in which Darwin had placed the doctrine of -evolution as his great achievement. The following eloquent passage -occurs on page 247 of “Darwiniana”:-- - - “None have fought better, and none have been more fortunate, than - Charles Darwin. He found a great truth trodden underfoot, reviled - by bigots, and ridiculed by all the world; he lived long enough - to see it, chiefly by his own efforts, irrefragibly established - in science,...” - -In the impressive speech in which Huxley handed over the statue of -Darwin to the Prince of Wales, as representative of the Trustees of -the British Museum, on June 9th, 1885 (“Darwiniana,” p. 248), the -references to Darwin are most consistent with the view that the support -to evolution was held by the speaker to be the great work of his life. -Natural selection is not mentioned. - -The next publication on this subject by Huxley is the celebrated -chapter “On the Reception of the ‘Origin of Species,’” in the second -volume of the great “Life and Letters.” In this chapter he speaks -rather more confidently about natural selection than in some of the -earlier essays and in the later speeches:-- - - “The reality and the importance of the natural processes on which - Darwin founds his deductions are no more doubted than those - of growth and multiplication; and, whether the full potency - attributed to them is admitted or not, no one doubts their vast - and far-reaching significance.” - -But of evolution he speaks far more strongly:-- - - “To any one who studies the signs of the times, the emergence - of the philosophy of Evolution, [“bound hand and foot and - cast into utter darkness during the millennium of theological - scholasticism”] in the attitude of claimant to the throne of the - world of thought, from the limbo of hated and, as many hoped, - forgotten things, is the most portentous event of the nineteenth - century.” - -And for this he gives Darwin the credit. - -Later on he indicates the sense in which his keen appreciation of -natural selection is to be understood. Thus, such strong statements as-- - - “... the publication of the Darwin and Wallace papers in 1858, - and still more that of the ‘Origin’ in 1859, had the effect ... - of the flash of light, which to a man who has lost himself in a - dark night, suddenly reveals a road which, whether it takes him - straight home or not, certainly goes his way”; - -and-- - - “The facts of variability, of the struggle for existence, of - adaptation to conditions, were notorious enough; but none of - us had suspected that the road to the heart of the species - problem lay through them, until Darwin and Wallace dispelled - the darkness, and the beacon-fire of the ‘Origin’ guided the - benighted,” - -if they stood alone, might naturally be interpreted as an unqualified -testimony to the permanent truth of natural selection. But this -interpretation is expressly excluded:-- - - “Whether the particular shape which the doctrine of evolution, as - applied to the organic world, took in Darwin’s hands, would prove - to be final or not, was, to me, a matter of indifference. In my - earliest criticisms of the ‘Origin’ I ventured to point that its - logical foundation was insecure ...; and that insecurity remains.” - -Its value for Huxley was that it was “incomparably more probable than -the creation hypothesis”; that it was “a hypothesis respecting the -origin of known organic forms, which assumed the operation of no causes -but such as could be proved to be actually at work”; that it provided -“clear and definite conceptions which could be brought face to face -with facts and have their validity tested”; that it freed us “for ever -from the dilemma--refuse to accept the creation hypothesis, and what -have you to propose that can be accepted by any cautious reasoner?” -Indeed, the hypothesis did away with this dilemma, even if it were -itself to disappear; for “if we had none of us been able to discern -the paramount significance of some of the most patent and notorious of -natural facts, until they were, so to speak, thrust under our noses, -what force remained in the dilemma--creation or nothing? It was obvious -that, hereafter, the probability would be immensely greater, that -the links of natural causation were hidden from our purblind eyes, -than that natural causation should be incompetent to produce all the -phenomena of nature.” - -Therefore, “the only rational course for those who had no other object -than the attainment of truth, was to accept ‘Darwinism’ as a working -hypothesis, and see what could be made of it.” Furthermore, “Whatever -may be the ultimate fate of the particular theory put forth by Darwin, -... all the ingenuity and all the learning of hostile critics has not -enabled them to adduce a solitary fact, of which it can be said, this -is irreconcilable with the Darwinian theory.” - -Taking this argument as a whole, it seems to me to amount to the words -of Mercutio quoted at the beginning of this chapter. - -In the following year (1888) Huxley wrote the Obituary Notice of -Darwin for the Proceedings of the Royal Society: it is reprinted in -“Darwiniana” (pp. 253 _et seq._). In this admirable essay the author -recognises that Darwin evidently accepted evolution before he could -offer any explanation of the motive cause by which that process -took place. The theory of descent with modification had often been -thought of before, “but in the eyes of the naturalist of the ‘Beagle’ -(and, probably, in those of most sober thinkers), the advocates of -transmutation had done the doctrine they expounded more harm than -good.” Huxley speaks of the “Origin” as “one of the hardest books to -master,” in this agreeing with Hooker (see p. 111). - -In this essay Huxley gives a clear and excellent statement of natural -selection, prefaced by these words (p. 287):-- - - “Although, then, the present occasion is not suitable for any - detailed criticism of the theory, or of the objections which have - been brought against it, it may not be out of place to endeavour - to separate the substance of the theory from its accidents; and - to shew that a variety not only of hostile comments, but of - friendly would-be improvements, lose their _raison d’être_ to the - careful student.” - -Then follows a brief but epigrammatic description, such as only Huxley -could have written, of the theory, and some of the chief arguments -which have revolved round it. Occasionally he speaks as if he were -stating his own opinion as well as Darwin’s, but throughout it seems -to me that his object is not to give his own views but to write a fair -and clear account of Darwin’s theory, and to defend it from a number -of criticisms and modifications which have been, from time to time, -brought forward. - -“Darwiniana” was published in 1893, and this is the date of the -Preface, in which Huxley speaks of-- - - “... the ancient doctrine of Evolution, rehabilitated and placed - upon a sound scientific foundation, since, and in consequence of, - the publication of the ‘Origin of Species....’” - -He thinks that readers will admit that in the first two essays (see -pages 124–128 of the present volume)-- - - “... my zeal to secure fair play for Mr. Darwin, did not drive - me into the position of a mere advocate; and that, while doing - justice to the greatness of the argument, I did not fail to - indicate its weak points. I have never seen any reason for - departing from the position which I took up in these two essays; - and the assertion which I sometimes meet with nowadays, that I - have ‘recanted’ or changed my opinions about Mr. Darwin’s views, - is quite unintelligible to me.” - - “As I have said in the seventh essay, [see pages 131, 132 of the - present volume] the fact of evolution is to my mind sufficiently - evidenced by palæontology; and I remain of the opinion expressed - in the second, that until selective breeding is definitely proved - to give rise to varieties infertile with one another, the logical - foundation of the theory of natural selection is incomplete.” - -It is therefore clear, as I have before stated, that Huxley, in 1893, -re-stated his criticisms and qualifications of thirty years before, -and expressed his conviction anew of the validity of the objections -which he then raised against a full and complete acceptance of natural -selection. - -We now come to the last and most significant of all Huxley’s utterances -on evolution and natural selection, made on two great occasions in the -last year of his life. Lord Salisbury, in his eloquent and interesting -Presidential Address to the British Association at Oxford (August 8th, -1894), had said of Darwin:-- - - “He has, as a matter of fact, disposed of the doctrine of the - immutability of species.... Few now are found to doubt that - animals separated by differences far exceeding those that - distinguish what we know as species have yet descended from - common ancestors.” - -While thus completely admitting evolution in the organic world, Lord -Salisbury attacked natural selection on two grounds--first, on the -insufficiency of the time allowed by physicists for a process which -is, of necessity, extremely slow in its operation; secondly, on the -ground that “we cannot demonstrate the process of natural selection in -detail; we cannot even, with more or less ease, imagine it.” And his -main objection under this head was the supposed difficulty in securing -the union of successful variations. The actual words have been already -quoted on page 83, where it was shown that the criticism does not apply -to natural selection, but to a theory mistaken by the speaker for that -of Darwin. Curiously enough, the first objection of the insufficiency -of time was the indirect cause of a subsequent trenchant criticism by -Professor Perry of the line of mathematical reasoning on which the -limit had been fixed. - -Huxley was called on to second the vote of thanks, and his speech had -evidently been considered with the greatest care. I quote the passages -which bear on evolution and natural selection from the _Times_ of -August 9th, 1894, in which a _verbatim_ report is furnished:-- - - “... As one of those persons who for many years past had made - a pretty free use of the comfortable word ‘evolution,’ let him - remind them that 34 years ago a considerable discussion, to which - the President had referred, took place in one of their sectional - meetings upon what people frequently called the ‘Darwinism - question,’ but which on that occasion was not the Darwinism - question, but the very much deeper question which lay beneath - the Darwinism question--he meant the question of evolution.... - The two doctrines, the two main points, for which these men - [Sir John Lubbock, Sir J. Hooker, and the speaker] fought were - that species were mutable, and that the great variety of animal - forms had proceeded from gradual and natural modification of the - comparatively few primitive forms....” - -After alluding to the revolution in thought which had taken place in -thirty-four years, he said:-- - - “As he noted in the presidential address to which they had just - listened with such well-deserved interest, he found it stated on - that which was then and at this time the highest authority for - them, that as a matter of fact the doctrine of the immutability - of species was disposed of and gone. He found that few were - now found to doubt that animals separated by differences far - exceeding those which they knew as species were yet descended - from a common ancestry. Those were their propositions; those - were the fundamental principles of the doctrine of evolution. - Darwinism was not evolution, nor Spencerism, nor Hæckelism, nor - Weismannism, but all these were built on the fundamental doctrine - which was evolution, which they maintained so many years, and - which was that upon which their President had put the seal of his - authority that evening....” - -Huxley thus hailed the statements of the President in favour of -evolution, while the attacks on natural selection he merely met by -saying that the address would have made a good subject for discussion -in one of the sections, and by insisting with impressive solemnity that -evolution was a very different thing from natural selection, thereby -implying that the former would be unaffected by the fate of the latter. - -The second occasion was between three and four months later, when -Huxley spoke at the Anniversary Dinner of the Royal Society, November -30th, 1894, after having been awarded the Darwin Medal at the afternoon -meeting. I quote his words from the _verbatim_ report of the _Times_ -for December 1st:-- - - “... I am as much convinced now as I was 34 years ago that - the theory propounded by Mr. Darwin, I mean that which he - propounded--not that which has been reported to be his by too - many ill-instructed, both friends and foes--has never yet been - shewn to be inconsistent with any positive observations, and if - I may use a phrase which I know has been objected to and which - I use in a totally different sense from that in which it was - first proposed by its first propounder, I do believe that on - all grounds of pure science it ‘holds the field,’ as the only - hypothesis at present before us which has a sound scientific - foundation.... I am sincerely of opinion that the views which - were propounded by Mr. Darwin 34 years ago may be understood - hereafter as constituting an epoch in the intellectual history of - the human race. They will modify the whole system of our thought - and opinion, our most intimate convictions. But I do not know, I - do not think anybody knows, whether the particular views which he - held will be hereafter fortified by the experience of the ages - which come after us; ... whether the particular form in which - he has put them before us (the Darwinian doctrines) may be such - as is finally destined to survive or not is more, I venture to - think, than anybody is capable at this present moment of saying.” - -It is unnecessary to say anything about this passage, which fitly sums -up and sets the seal on the long series of quotations I have felt -obliged to make. - -It may not be out of place, however, to state in a few words why -many naturalists, including the present writer, are not inclined to -accept the extremely cautious and guarded language of one upon whom, -with regard to so many other subjects, they have ever looked as their -teacher and guide. Concerning the verification of a hypothesis, Huxley -said in his lectures to working men (“Darwiniana,” pages 367, 368)-- - - “... that the more extensive verifications are,--that the more - frequently experiments have been made, and results of the same - kind arrived at,--that the more varied the conditions under which - the same results are attained, the more certain is the ultimate - conclusion....” - -And again-- - - “In scientific enquiry it becomes a matter of duty to expose a - supposed law to every possible kind of verification, and to take - care, moreover, that this is done intentionally, and not left to - a mere accident....” - -It may well be that the length of time required before an -artificially-selected race will exhibit, when interbred with the parent -species, phenomena of hybridism similar to those which are witnessed -when distinct natural species are interbred--will be fatal to the -production of this important line of evidence. But there is nothing to -hinder us from holding the reasonable belief that such evidence might -be obtained if we had command of the necessary conditions; and in the -meantime other evidence of the most satisfactory kind is accumulating, -and on a vast scale. Whenever a naturalist approaches a problem in the -light of the theory of natural selection, and is able, by its aid, -to predict a conclusion which subsequent investigation proves to be -correct, he is helping in the production of evidence in favour of the -theory. When a naturalist has found the formula “if natural selection -be true so-and-so ought to happen” the safest of all guides into -the unknown, when it has brought him success many times and in very -different directions, when he knows that many other workers in other -fields of biological inquiry have had a similarly happy experience, he -gradually comes to feel a profound confidence in the permanent truth -and the far-reaching importance of the great theory which has served -him so well. - - - - -CHAPTER XIX. - -THE DIFFICULTY WITH WHICH THE “ORIGIN” WAS UNDERSTOOD. - - -Even earlier than Huxley, H. C. Watson wrote warmly accepting natural -selection. In his letter, which is dated November 21st, 1859, he said:-- - - “Your leading idea will surely become recognised as an - established truth in science--_i.e._ ‘Natural Selection.’ It has - the characteristics of all great natural truths, clarifying what - was obscure, simplifying what was intricate, adding greatly to - previous knowledge. You are the greatest revolutionist in natural - history of this century, if not of all centuries.” - -[Sidenote: MISUNDERSTANDING OF THE THEORY.] - -For some years to come, however, such views as these were the -exception, as will soon be shown. - -The Duke of Argyll has argued (_Nineteenth Century_, December, -1887) that the success of “Natural Selection” has followed from the -convincing character of the words used, scientific men (“the populace -of science” he calls them) being so easily led by the power of loose -analogies that they have been convinced of the truth of the principle -because they are familiar with Nature on the one hand, and selection as -a process on the other! - -As I am not aware that this preposterous suggestion has ever been -publicly disproved, and since therefore some readers of the journal in -question may have been misled by it, I have collected much evidence, -which proves that the principle of natural selection was only absorbed -with the very greatest difficulty, and that the words used in -describing it for a long time entirely failed to inform even eminent -scientific men of the essential characteristics of the theory itself, -and certainly failed most signally to convince them. Conviction came -very gradually as the theory was slowly understood and was seen to -offer an intelligible explanation of an immense and ever-increasing -number of facts. - -I will now bring together quotations from Darwin’s letters in 1859 and -1860, showing how soon he came to realise the difficulty with which -natural selection was understood, and to feel that he might have been -more successful with some other title. - -In 1859 he wrote to Dr. W. B. Carpenter--“I have found the most -extraordinary difficulty in making even able men understand at what -I was driving.” The remaining quotations are all taken from letters -written in 1860. By the middle of this year, when he was feeling -oppressed by hostile reviews and unfair and ignorant criticisms (“I -am getting wearied at the storm of hostile reviews, and hardly any -useful”), he often alludes to the failure of opponents to understand -his theory. Thus, in a letter to Hooker (June 5th), he says:-- - - “This review, however, and Harvey’s letter have convinced me that - I must be a very bad explainer. Neither really understand what - I mean by Natural Selection.... I hope to God you will be more - successful than I have been in making people understand your - meaning.” - -He says almost the same thing in a letter to Lyell (June 6th):-- - - “... I am beginning to despair of ever making the majority - understand my notions.... I must be a very bad explainer. I - hope to Heaven that you will succeed better. Several reviews - and several letters have shown me too clearly how little I am - understood. I suppose ‘Natural Selection’ was a bad term; ... - I can only hope by reiterated explanations finally to make the - matter clearer.” - -Writing to Asa Gray, he says:-- - - “... I have had a letter of fourteen folio pages from Harvey - against my book, with some ingenious and new remarks; but it is - an extraordinary fact that he does not understand at all what I - mean by Natural Selection.” - -Later on, he again wrote to Lyell:-- - - “Talking of ‘natural selection’; if I had to commence _de novo_, - I would have used ‘natural preservation.’ For I find men like - Harvey of Dublin cannot understand me, though he has read the - book twice. Dr. Gray of the British Museum remarked to me that, - ‘_selection_ was obviously impossible with plants! No one could - tell him how it could be possible!’ And he may now add that the - author did not attempt it to him!” - -And still later he wrote asking Lyell’s advice as to additions to a -new edition of the “Origin,” saying:--“I would also put a note to -‘Natural Selection,’ and show how variously it has been misunderstood.” -This note is to be found on page 63 of the sixth edition. In it he -tells us that some writers have “even imagined that natural selection -induces variability,” instead of merely preserving it; others that -natural selection “implies conscious choice in the animals which become -modified”; others that it is set up “as an active power or Deity.” -In writing (December) to Murray about a new edition of the “Origin,” -he alludes to the “many corrections, or rather additions, which I -have made in hopes of making my many rather stupid reviewers at least -understand what is meant.” - -He seems to have retained a very vivid recollection of the difficulty -with which his theory was understood at first; thus he tells us in his -“Autobiography”:-- - - “I tried once or twice to explain to able men what I meant by - Natural Selection, but signally failed.” - -Why the term “natural selection” was chosen by Darwin is very clearly -shown in the three following quotations from letters to distinguished -scientific men, which were probably written in answer to attacks or -criticisms on this very point. - -He writes to Lyell in 1859, “Why I like the term is that it is -constantly used in all works on breeding.” - -Writing to H. G. Bronn in 1860, he explains his motives with great -clearness and force:-- - - “Several scientific men have thought the term ‘Natural Selection’ - good, because its meaning is _not_ obvious, and each man could - not put on it his own interpretation, and because it at once - connects variation under domestication and nature.... Man has - altered, and thus improved the English race-horse by _selecting_ - successive fleeter individuals; and I believe, owing to the - struggle for existence, that similar _slight_ variations in a - wild horse, _if advantageous to it_, would be _selected_ or - _preserved_ by nature; hence Natural Selection.” - -In 1866 he wrote to Wallace, comparing the term with that which we owe -to Herbert Spencer:-- - - “I fully agree with all that you say on the advantages of H. - Spencer’s excellent expression of ‘the survival of the fittest.’ - This however had not occurred to me till reading your letter. It - is, however, a great objection to this term that it cannot be - used as a substantive governing a verb; and that it is a real - objection I infer from H. Spencer continually using the words, - natural selection. I formerly thought, probably in an exaggerated - degree, that it was a great advantage to bring into connection - natural and artificial selection; this indeed led me to use a - term in common, and I still think it some advantage.... The term - Natural Selection has now been so largely used abroad and at - home, that I doubt whether it could be given up, and with all its - faults I should be sorry to see the attempt made. Whether it will - be rejected must now depend ‘on the survival of the fittest.’ As - in time the term must grow intelligible the objections to its use - will grow weaker and weaker. I doubt whether the use of any term - would have made the subject intelligible to some minds, clear - as it is to others; for do we not see even to the present day - Malthus on Population absurdly misunderstood? This reflection - about Malthus has often comforted me when I have been vexed at - the mis-statement of my own views.” - -A large number of critics not only failed to understand natural -selection, but they asserted that it was precisely the same theory as -that advanced by Lamarck or one of the other writers on evolution -before Darwin. This seems almost incredible to us at the present -day, when the biological world is divided into two sections on the -very subject, and when it is generally recognised that Lamarck’s -theory would be, if it were proved to be sound, a formidable rival to -natural selection as a motive cause of evolution. But the following -quotations--a few among many--leave no doubt whatever upon the subject. - -Evidence on this point reached Darwin almost immediately after the -appearance of the “Origin.” Thus he writes to Hooker on December 14th, -1859:-- - - “Old J. E. Gray, at the British Museum, attacked me in fine - style: ‘You have just reproduced Lamarck’s doctrine, and nothing - else, and here Lyell and others have been attacking him for - twenty years, and because _you_ ... say the very same thing, they - are all coming round; it is the most ridiculous inconsistency,’ - &c. &c.” - -In the following year, Wilberforce, Bishop of Oxford, writing in the -_Quarterly Review_ for July, 1860, appeals to Lyell, - - “in order that with his help this flimsy speculation may be as - completely put down as was what in spite of all denials we must - venture to call its twin though less-instructed brother, the - ‘Vestiges of Creation.’” - -Again, Dr. Bree, in “Species not Transmutable,” says: - - “The only real difference between Mr. Darwin and his two - predecessors, [Lamarck and the “Vestiges”] is this:--that while - the latter have each given a mode by which they conceive the - great changes they believe in have been brought about, Mr. Darwin - does no such thing.” - -One of the most interesting of the countless examples of -misunderstanding is contained in a recently published letter from W. S. -Macleay to Robert Lowe.[H] This letter was written from Elizabeth Bay, -and is dated May, 1860, evidently just after the first edition of the -“Origin,” a copy of which had been sent by Robert Lowe, had been read -by Macleay. - - “Again if this primordial cell had a Creator, as Darwin seems - to admit, I do not see what we gain by denying the Creator, as - Darwin does, all management of it after its creation. Lamarck - was more logical in supposing it to have existed of itself from - all eternity--indeed this is the principal difference that I - see between this theory of Darwin’s and that of Lamarck, who - propounded everything essential in the former theory, in a work - now rather rare--his ‘Philosophie Zoologique.’ But you may see - an abridgment of it in so common a book as his ‘Histoire Nat. - des Animaux Vertébrés,’ vol. i., pp. 188, _et seq._--Edit. 1818, - where the examples given of natural selection are the gasteropod - molluscs.... Natural selection (sometimes called ‘struggles’ by - Darwin) is identical with the ‘Besoins des Choses’ of Lamarck, - who, by means of his hypothesis, for instance, assigns the - constant stretching of the neck to reach the acacia leaves as - the cause of the extreme length of it in the giraffe; much in - the same way the black bear, according to Darwin, became a - whale, which I believe as little as his other assertion that our - progenitors anciently had gills--only they had dropped off by - want of use in the course of myriads of generations.” - -I had long been anxious to possess a copy of the first edition of the -“Origin,” and was fortunate enough to come across one about the time -when Macleay’s letter was pointed out to me by my wife. I opened the -title-page, and found upon it the signature “W. S. Macleay”; it must -have been the very volume given him by Robert Lowe, which Macleay had -read and believed he had been fairly criticising. Out of Macleay’s -volume, therefore, I quote the sentences he referred to in his letter. - -Darwin’s real statement about the black bear which “became a whale” is -to be found on page 184:-- - - “In North America the black bear was seen by Hearne swimming - for hours with widely open mouth, thus catching, like a whale, - insects in the water. Even in so extreme a case as this, if - the supply of insects were constant, and if better adapted - competitors did not already exist in the country, I can see - no difficulty in a race of bears being rendered, by natural - selection, more and more aquatic in their structure and habits, - with larger and larger mouths, till a creature was produced as - monstrous as a whale.” - -The statement about the gills which “dropped off by want of use” -becomes in the original (p. 191):-- - - “In the higher vertebrata the branchiæ have wholly - disappeared--the slits on the sides of the neck and the loop-like - course of the arteries still marking in the embryo their former - position.” - -Although the hypothetical case of the black bear--carefully guarded as -it is--does not now appear to us at all extravagant (indeed, in the -cleft cheeks of the goat-sucker we have a precisely analogous case), -Darwin seems to have thought it unsuitable, probably because it became -an easy butt for ignorant ridicule. We find accordingly that in the -second and all subsequent editions everything after the word “water” -is omitted, while “almost” is inserted before “like a whale.” He was -alluding to this passage when he wrote to Lyell (December 22nd, 1859): -“Thanks about ‘Bears,’ a word of ill-omen to me.” Furthermore, Andrew -Murray[I] says, concerning the sentences as they stand in the first -edition:-- - - “In quoting this, I do not at all mean to give it as a fair - illustration of Mr. Darwin’s views. I only refer to it as - indicating the extent to which he is prepared to go. The example - here given I look upon (as I have reason to know that Mr. Darwin - himself does) merely as an extreme and somewhat extravagant - illustration, imagined expressly to show in a forcible way how - ‘natural selection’ would operate in making a mouth bigger and - bigger, because more advantageous.” - - - - -CHAPTER XX. - -THE DIFFICULTY WITH WHICH THE “ORIGIN” WAS UNDERSTOOD -(_continued_)--VIEWS ON SPONTANEOUS GENERATION. - - -The history of opinion on evolution and natural selection, in the years -which followed the publication of the “Origin,” can be traced in the -titles of the papers and subjects of discussion at successive meetings -of the British Association. In the Presidential Address delivered by -Professor Newton to the Biological Section of the Manchester meeting in -1887, there is a most interesting account of the struggles which took -place:-- - - “The ever-memorable meeting ... at Oxford in the summer of 1860 - saw the first open conflict between the professors of the new - faith and the adherents of the old one. Far be it from me to - blame those among the latter who honestly stuck to the creed in - which they had educated themselves; but my admiration is for the - few dauntless men who, without flinching from the unpopularity - of their cause, flung themselves in the way of obloquy, and - impetuously assaulted the ancient citadel in which the sanctity - of ‘species’ was enshrined and worshipped as a palladium. However - strongly I myself sympathised with them, I cannot fairly state - that the conflict on this occasion was otherwise than a drawn - battle; and thus matters stood when in the following year the - Association met in this city [Manchester]. That, as I have - already said, was a time of ‘slack water.’ But though the ancient - beliefs were not much troubled, it was for the last time that - they could be said to prevail; and thus I look upon our meeting - in Manchester 1861 as a crisis in the history of biology. All - the same, the ancient beliefs were not allowed to pass wholly - unchallenged; and one thing is especially to be marked--they - were challenged by one who was no naturalist at all, by one who - was a severe thinker no less than an active worker; one who was - generally right in his logic, and never wrong in his instinct; - one who, though a politician, was invariably an honest man--I - mean the late Professor Fawcett. On this occasion he brought the - clearness of his mental vision to bear upon Mr. Darwin’s theory, - with the result that Mr. Darwin’s method of investigation was - shewn to be strictly in accordance with the rules of deductive - philosophy, and to throw light where all was dark before.” - -Professor Newton specially alluded to this interesting case of -Professor Fawcett as illustrating his conviction that the theory of -natural selection-- - - “did not, except in one small point, require a naturalist to - think it out and establish its truth.... But in order to see the - effect of this principle upon organic life the knowledge--the - peculiar knowledge--of the naturalist was required. This was - the knowledge of those slight variations which are found in - all groups of animals and plants.... Herein lay the triumph - of Mr. Darwin and Mr. Wallace. That triumph, however, was not - celebrated at Manchester. The question was of such magnitude as - to need another year’s incubation, and the crucial struggle came - a twelvemonth later when the Association met at Cambridge. The - victory of the new doctrine was then declared in a way that none - could doubt. I have no inclination to join in the pursuit of the - fugitives.” - -There is reason to believe that Professor Newton’s impressions of the -result of the celebrated meeting of the British Association at Oxford -in 1860 are more accurate than those of the eyewitness quoted in the -“Life and Letters.” The latter has pictured a brilliant triumph for -Huxley in the renowned duel with the Bishop of Oxford. But I have -been told by more than one of the audience that Huxley was really too -angry to speak effectively, nor is this to be wondered at, considering -the extreme provocation. Mr. William Sidgwick, who was present and -sympathised warmly with Huxley, has told me that this was his opinion. -I have heard the same from the Rev. W. Tuckwell, who also quoted a -remark of the late Professor Rolleston tending in the same direction. -Mr. Tuckwell said that it was clear that the audience as a whole -was not carried away by Huxley’s speech, but, on the contrary, was -obviously shocked at it; and he contrasted that occasion with another -at which he was also present, in the North, several years later, -when Huxley replied to an opponent who, like the bishop, appealed to -the theological prejudices of his hearers. But by that time the new -teachings had been absorbed, and Huxley gained a signal triumph. - -[Sidenote: OPPOSITION.] - -It must not be supposed that Darwin was by any means indifferent to the -attacks on his views. On the contrary, his sensitive nature was greatly -depressed by the violent and often most unfair criticisms to which he -was subjected, although beneath this evident disturbance lay the firm -conviction that he had seen the truth, and that the truth would in the -end be seen by others. - -After the great fight with the bishop at the British Association at -Oxford, he wrote to Hooker (July 2nd, 1860):-- - - “I have read lately so many hostile views, that I was beginning - to think that perhaps I was wholly in the wrong, and that ---- - was right when he said the whole subject would be forgotten in - ten years; but now that I hear that you and Huxley will fight - publicly (which I am sure I never could do), I fully believe that - our cause will, in the long-run, prevail.” - -Looking at the history of opinion on this subject, the slowness with -which the new ideas were absorbed appears remarkable. Even so able a -man as the late Professor Rolleston wrote in 1870 (“Forms of Animal -Life,” Introduction, p. xxv., First Edition) the following carefully -guarded sentences, which, it is to be noted, deal with evolution rather -than natural selection. Speaking of “the theory of evolution with which -Mr. Darwin’s name is connected,” Rolleston says:-- - - “Many of the peculiarities which attach to biological - classifications would thus receive a reasonable explanation; but - where verification is, _ex hypothesi_, impossible, such a theory - cannot be held to be advanced out of the region of probability. - The acceptance or rejection of the general theory will depend, as - does the acceptance or rejection of other views supported merely - by probable evidence, upon the particular constitution of each - individual mind to which it is presented!” - -It was too much to expect that many of the older scientific men would -retain sufficient intellectual flexibility to be able to recognise, as -Lyell had, that the facts of nature were explained and predicted better -by the new views than by those in which they had grown up. Darwin -thoroughly understood this, and, writing to his friends, maintained -that the fate of his views was in the hands of the younger men. - -A grand yet simple conception like that of natural selection, -explaining and connecting together innumerable facts which people had -previously explained differently, or had become accustomed to regard as -inexplicable, must always remain as a stumbling-block to the majority -of those who have reached or passed middle life before its first -appearance. - -Hardly anything is more characteristic of Darwin than the tone with -which he wrote to acknowledged opponents. Thus his letters to L. -Agassiz (1868), Quatrefages (1869 or 1870), and Fabre (1880), are -models of the way in which a correspondence which would present -peculiar difficulties to most people may be conducted. In these letters -there is not the least attempt to slur over or minimise the points of -wide difference; on the contrary, they are most candidly stated, but -with so much respect and sympathy, and with such marked appreciation -of the knowledge he had gained from his correspondent, that the reader -must have regretted the divergence of opinion as greatly as the writer. - -Tyndall has given a very interesting and pathetic account of the -evident distress with which Professor L. Agassiz, chief of the -opponents of Darwin in America, recognised the success of the -teachings he could not accept. - - “Sprung from a race of theologians, this celebrated man combated - to the last the theory of natural selection. One of the many - times I had the pleasure of meeting him in the United States - was at Mr. Winthrop’s beautiful residence at Brookline, near - Boston. Rising from luncheon, we all halted, as if by a common - impulse in front of a window, and continued there a discussion - which had been started at table. The maple was in its autumn - glory; and the exquisite beauty of the scene outside seemed, in - my case, to interpenetrate without disturbance the intellectual - action. Earnestly, almost sadly, Agassiz turned and said to the - gentlemen standing round, ‘I confess that I was not prepared to - see this theory received as it has been by the best intellects - of our time. Its success is greater than I could have thought - possible.’”[J] - -The history of science can hardly supply anything more sad than the -blight which may fall on a man’s career because he is unable, from -conscientious motives, to use some great means of advance. Such a -weapon for the progress of science was provided by the Darwinian -theory, and men were to be henceforth divided according to their use -or neglect of the new opportunities. Men who up to that time had been -equals were to be for ever separated, some to press forward in the -front rank of scientific discovery, others to remain as interesting -relics of a byegone age. - -It is hardly necessary to say that this does not apply to men, like -Agassiz, who had already left their mark deep upon the science of their -day, but it has a very real application to those men whose position -was to be estimated by work done after the year 1858. - -In the midst of those years of struggle and anxiety which followed the -appearance of the “Origin,” we meet with another instance of the same -extraordinary foresight which appeared in his contention in favour of -the persistence of the great oceans and continental areas. I refer to -his views on spontaneous generation--a very ancient belief, and one -which from time to time has been the will-o’-the-wisp of biological -speculation, leading it into all kinds of fruitless and dangerous -regions.[K] - -Dr. Carpenter’s “Introduction to the Study of Foraminifera” had been -reviewed in the _Athenæum_ (March 28th, 1863), the writer attacking -evolution and favouring spontaneous generation, or, as it was then -called, heterogeny. Darwin wrote to Hooker, who had lent him a copy of -the paper, “Who would have ever thought of the old stupid _Athenæum_ -taking to Oken-like transcendental philosophy written in Owenian -style!... It will be some time before we see ‘slime, protoplasm, etc.,’ -generating a new animal.... It is mere rubbish, thinking at present of -the origin of life; one might as well think of the origin of matter.” -In 1871 he wrote:-- - - “It is often said that all the conditions for the first - production of a living organism are now present, which could - ever have been present. But if (and oh! what a big if!) we could - conceive in some warm little pond, with all sorts of ammonia - and phosphoric salts, light, heat, electricity, etc., present, - that a proteine compound was chemically formed ready to undergo - still more complex changes, at the present day such matter would - be instantly devoured or absorbed, which would not have been the - case before living creatures were formed.” - -About 1870 Dr. H. C. Bastian began working on the subject, and brought -forward in his “Origin of Lowest Organisms” (1871), and “The Beginnings -of Life” (1872), what he believed to be conclusive evidence of the -truth of spontaneous generation, for which he proposed the term -Archebiosis. His enthusiasm and strong convictions were contagious, and -for a time the belief spread rather widely, although it soon collapsed -before the researches and arguments of Pasteur, Tyndall, and Huxley. -Darwin read “The Beginnings of Life,” and wrote about it to Wallace -(August 28th, 1872) as follows:-- - - “His [Bastian’s] general argument in favour of Archebiosis is - wonderfully strong, though I cannot think much of some few of - his arguments. The result is that I am bewildered and astonished - by his statements, but am not convinced, though, on the whole, - it seems to me probable that Archebiosis is true. I am not - convinced, partly I think owing to the deductive cast of much of - his reasoning; and I know not why, but I never feel convinced - by deduction, even in the case of H. Spencer’s writings.... I - must have more evidence that germs, or the minutest fragments of - the lowest forms, are always killed by 212° of Fahr.... As for - Rotifers and Tardigrades being spontaneously generated, my mind - can no more digest such statements, whether true or false, than - my stomach can digest a lump of lead.” - - - - -CHAPTER XXI. - -VARIATION OF ANIMALS AND PLANTS UNDER DOMESTICATION: PANGENESIS (1868). - - -We now come to consider the succession of invaluable works produced by -Darwin after the appearance of the “Origin,” the last of which--that on -Earthworms--was published about six months before his death. - -Darwin’s method of bringing these results before the world was -somewhat different from that most generally adopted by scientific men -in this country, although of common occurrence in Germany. The great -majority of scientific facts are here published by the proceedings -or transactions of scientific societies, or in special journals; and -although a scientific man frequently brings together his general -results into a volume for the public, the original communications -remain as the detailed exposition of his researches. - -Darwin, too, wrote a very large number of memoirs for the scientific -societies, as may be seen from the list in Appendix III. of the “Life -and Letters,” but the volumes which he subsequently published included -_all_ the previous details, with the addition of much new matter, and -it is these volumes rather than the original communications which form -the authoritative statement of his investigations. Such a method was -possible and desirable with the subjects upon which he worked, all -of which were of great interest to the thinking part of the general -public, as well as to the experts; but in less attractive subjects it -is not probable that the plan could be carried out in this country with -any prospect of success. - -It has already been stated that Darwin looked on the “Origin of -Species” as a short abstract of a greater work he intended to publish. -It is likely that he at first contemplated a comprehensive work like -the “Origin” itself, but soon found that his notes on domesticated -animals and plants, the general results of which had been condensed -into the first three chapters of the “Origin,” would form a work -more than twice the size of the latter. He began arranging these -notes on January 9th, 1860 (January 1st is the date given in the -“Autobiography”), as soon as the second edition of the “Origin” was off -his hands, but his “enormous correspondence,” as he calls it in the -“Autobiography,” with friends about the “Origin,” and the reviews and -discussions upon it, must have occupied a large part of his time; and -then there was the third edition to bring out (published April, 1861). -This edition must have cost much labour, as many parts were modified -and enlarged to meet the objections or misunderstanding of reviewers. - -Francis Darwin tells us that the third chapter of “Animals and Plants, -&c.,” was still on hand at the beginning of 1861. His work on this book -was furthermore interrupted by illnesses and by other researches. -Thus, during 1860 he worked at Drosera, and during the latter part -of 1861 and beginning of 1862 at the fertilisation of orchids. In -his diary for 1866 we meet with the entry, “_Nov. 21st_--Finished -‘Pangenesis,’” and later on, “_Dec. 22nd_--Began concluding chapter -of book.” In this year, too, he brought out the fourth edition of the -“Origin.” When the time for publication approached Darwin was much -disappointed at the dimensions of the work. It was not published till -January 30th, 1868, when it was proved that his fears were groundless, -for a second edition of 1,250 copies were required in the following -month, the 1,500 of the first edition having been all absorbed. - -This work is considered by some writers to be the greatest produced by -Darwin; but I think we shall be right in accepting his own opinion that -such words should be applied to the “Origin.” It is probable, however, -that this book stands second in importance in the splendid list of -works which have done so much to increase our knowledge of nature and -to inspire others to continue the good work. - -[Sidenote: ON VARIATION.] - -“The Variation of Animals and Plants under Domestication” opens with -a very clearly written account of natural selection; it proceeds to -treat of the domestic quadrupeds and birds, describing the differences -between the various breeds of each species, and making out as far as -possible the history of their development from each other and from the -wild stock. Cultivated plants are then treated in the same manner. -The first volume concludes with two most important chapters on -bud-variation and anomalous modes of reproduction, and on inheritance. - -The second volume deals with inheritance, crossing, effect of -conditions of life, sterility, hybridism, selection by man, causes -and laws of variability. Finally, all the main lines are brought to -a common centre in the wonderful chapter in which he discloses his -“provisional hypothesis of pangenesis.” This is of such interest, -and is so characteristic of its author’s power of viewing the most -divergent facts from a common standpoint, that it is desirable to give -a tolerably full account of it. - -The following is a brief statement of the various classes of facts -which Darwin attempted to connect by his hypothesis. - -_Reproduction_ is sexual and asexual, and the latter is of various -kinds, although their differences are more apparent than real. It may -be concluded that gemmation or budding, fission or division, the repair -of injuries, the maintenance of each part, and the growth of the embryo -“are all essentially the results of one and the same great power.” - -In parthenogenesis the ovum can develop without fertilisation, and -hence the union of germs from different individuals cannot serve as -an essential characteristic of sexual, as compared with asexual, -generation. Although sexually-produced individuals tend to vary far -more than those which are produced asexually, this is not always the -case, and the variability, when it occurs, is subject to the same -laws. Sexually-produced individuals very generally pass in development -from a lower to a higher grade; but this can hardly be said to occur in -certain forms, such as Aphis, etc. - -The differences between the two forms of reproduction being thus much -less than at first sight appears, we are led to inquire for the reason -why the more complex and difficult process is so universal. Sexual -reproduction appears to confer two benefits on organisms--(1) “When -species are rendered highly variable by changed conditions of life, -the free intercrossing of the varying individuals will tend to keep -each form fitted for its proper place in nature, and crossing can be -effected only by sexual generation”; (2) Many experiments tend to show -that free and wide intercrossing induces vigour in the offspring. - -Darwin concludes that the reason why the germ-cell perishes if it does -not unite with another from the opposite sex is simply because it -includes “too little formative matter for independent existence and -development.” He was led to this conclusion by the fact that the male -and female germ-cells “do not in ordinary cases differ in their power -of giving character to the embryo,” and also from experiments which -seemed to show that a certain number of pollen grains or of spermatozoa -may be required to fertilise a single seed or ovum. “The belief that -it is the function of the spermatozoa to communicate life to the ovule -seems a strange one, seeing that the unimpregnated ovule is already -alive, and continues for a considerable time alive.” - -It is very remarkable to note how largely Professor Weismann’s -conclusions on this subject were anticipated by this part of Darwin’s -work. - -_Graft hybrids._--The probability that a graft may alter the character -of the stock to which it is united, so that hybrid buds might be formed -by budding or grafting the tissues of distinct varieties or species, -would, if it became a certainty, prove the essential identity of -sexual and asexual reproduction; “for the power of combining in the -offspring the characters of both parents is the most striking of all -the functions of sexual generation.” - -_Direct action of the male element on the female._--Pollen from another -species is known to affect the mother-plant in certain cases. Thus -pollen from the lemon has caused stripes of lemon-peel in the fruit of -the orange; the peel is, of course, formed by the mother-plant, and -is quite different from the part which the male element is adapted to -affect--viz. the ovule. Similar cases are known among animals, as in -the celebrated example of Lord Morton’s mare. - -_Development._--The changes by which the embryo reaches maturity -differ immensely, even within the limits of the same compact group. -Forms which closely resemble each other in the mature state, and -are intimately related to each other, such as the various species -of lobster and crayfish, etc., pass through a totally different -developmental history. Hence we are led to believe in the complete -independence of “each structure from that which precedes and follows it -in the course of development.” - -_The functional independence of the elements or units of the body. -Variability and inheritance._--Variability generally results “from -changed conditions acting during successive generations.” The influence -is exerted on the sexual system, and if extreme, impotence tends to be -produced. Bud-variation proves that “variability is not necessarily -connected with the sexual system.” The inherited effects of use and -disuse of parts imply that the changes in the cells of a distant part -of the body affect the reproductive cells, so that the being produced -from one of these cells inherits the changes. “Nothing in the whole -circuit of physiology is more wonderful.” - -“Inheritance is the rule and non-inheritance the anomaly.” Inheritance -follows laws, such as the tendency for a character to appear at -corresponding ages in parent and offspring. Reversion “proves to us -that the transmission of a character and its development ... are -distinct powers.” Crossing strongly induces reversion. “Every character -which occasionally reappears is present in a latent form in each -generation.” - - * * * * * - -[Sidenote: PANGENESIS.] - -The hypothesis of pangenesis attempts to explain and connect together -all the facts and conclusions which have been summarised in the -preceding pages. This hypothesis assumes that each one of the -countless cells of which the body of a higher animal is composed throws -off a minute gemmule which, with those derived from other cells, exists -in the body, and when supplied with nutriment multiplies by division. -Each gemmule is capable of ultimate development into a cell similar -to the one from which it, either directly or indirectly, arose. Each -cell of the body dispatches its representative, as it were, to each -single germ-cell, and this explains how it is that the latter possess -the power of reproducing the likeness of the parent body. But the -germ-cells also receive dormant gemmules which may remain undeveloped -until some generation in the remote future. The development of the -gemmules into cells depends on their union with the developing cells -which precede them in the order of growth. Gemmules are thrown off -during each stage of growth and during maturity. - -This hypothesis of pangenesis is so called because the whole body is -supposed to produce the elements from which new individuals arise, the -germ-cells being only the union of these elements into clusters. - -The fact that hybrids may be produced by grafting, that the pollen can -act on the tissues of the female plant, and the male germ-cells on the -future offspring of the female, implies that the reproductive material -can exist and the reproductive processes take place in the tissues, and -that they are not confined to the germ-cells. - -The retention of dormant gemmules, and their passage from generation -to generation until their development, may seem improbable; but is it -more so than the _fact_ which their presence would explain--viz. the -transmission of latent structures and their ultimate reappearance? - -The development of the whole plant from a Begonia leaf implies that -these gemmules are very widely distributed through the tissues. - -The elective affinity of the gemmules for the cells which precede them -in growth may be paralleled by the affinity of the male and female -germ-cells, as we see in the preference of a plant for the pollen -grains of its own over those of closely-allied species, or by the -attraction of the minute germs of disease to certain tissues of the -body. - -It is possible that the numerous gemmules thrown off by the cells of -a complex structure, such as a feather, “may be aggregated into a -compound gemmule.” In the case of a petal, however, where parts as well -as the whole are apt to develop, as is seen in the case of “stripes of -the calyx assuming the colour and texture of the corolla,” it is more -probable that the gemmules are separate and free. The cell itself is a -complex structure, and we do not know whether its separate parts are -not developed from the separate gemmules of an aggregate. - -Such an hypothesis explains the fundamental similarity which has -already been shown to exist between all modes of reproduction. The -gemmules collected in bud or germ-cell are essentially similar; -and were it not for the special advantages of sexual reproduction -(increased vigour and more marked variation of offspring), we can well -believe that it would have been much less general. The formation of -graft-hybrids, and the action of the male element on the mother and on -future offspring, become intelligible. The antagonism between growth -and sexual reproduction in animals, and between increase by buds, etc., -and seeds in plants, can be understood by the use of gemmules in one -direction preventing their simultaneous use in another. - -The regrowth of an amputated part, as in the salamander or snail, -is explained by the presence and development of gemmules previously -thrown off from the part. The difficulty that a limb is produced of the -same age as that which was lost, and not a larval limb, and that the -cells with which the gemmules must unite at first are not those which -precede them in the course of growth, but mature cells, is met by the -consideration that this power is a special one adapted to meet special -dangers to certain parts of certain animals, and that it is therefore -probable that appropriate provision has been made by natural selection: -it may be in the form of “a stock of nascent cells or of partially -developed gemmules.” The existence of these latter in buds, and their -absence from sexual cells, may account for bud development being the -more direct and brief of the two. The much greater tendency to repair -lost parts in lower and younger forms may be due to the same cause. - -The occasional tendency of hybrids to resemble one parent in one part -and the other in another may be due to superabundance of gemmules in -the fertilised germ, those from one parent having “some advantage in -number, affinity, or vigour over those derived from the other parent.” -The general preponderance of one parent over the other may be similarly -explained. The cases in which “the colour or other characters of either -parent tend to appear in stripes or blotches” are to be understood by -the gemmules having an affinity for others of the same kind. - -_The sterility of hybrids_ is entirely due to the reproductive organs -being affected; in the case of plants they continue to propagate freely -by buds. The hybrid cells throw off hybrid gemmules which collect in -the buds but cannot do so in the reproductive organs. - -_Development and metamorphosis._--The remarkable facts of development -and metamorphosis are well explained by the hypothesis. Allied forms -may pass to a similar end through very dissimilar stages or conversely. -Parts may appear to develop within previously existing corresponding -parts, or they may appear within parts which are quite distinct. These -divergent facts are explained by the hypothesis, each part during each -stage being formed independently from the gemmules of the same part -in previous generations, and not, although it may appear to do so, -from the corresponding parts of earlier stages. In the process of time -certain parts during certain stages may be affected by use or disuse or -surroundings, and the parts of subsequent generations will be similarly -affected, because formed from correspondingly altered gemmules; but -this need not affect the other stages of the same parts. - -_Transposition and multiplication of parts._--The cases of abnormal -transposition or multiplication of organs--for instance, the -development of teeth in the palate or of pollen in the edge of a -petal--are to be explained by supposing that the gemmules unite with -wrong cells instead of, or as well as, the right ones; “and this would -follow from a slight change in their elective affinities.” Such slight -changes are known to occur; for instance, certain plants “absolutely -refuse to be fertilised by their own pollen, though abundantly fertile -with that of any other individual of the same species.” Inasmuch as the -cells of adjoining parts will often have nearly the same structure, we -can understand that some slight change in elective affinity may affect -a large area. Hence we can account for a crowd of horns on the head of -a sheep, or many spurs on the leg of a fowl, etc. Frequently repeated -parts are extremely liable to vary in number; in this case we have a -large number of closely allied gemmules and of points for their union, -and slight changes in elective affinity would be specially apt to -occur. - -VARIABILITY.--Changed conditions may lead to irregularity in the number -of gemmules derived from various parts of the body; deficiency in -number might cause variation in any part by leaving some of the cells -free to unite with allied gemmules. - -The direct action of surroundings, or the effect of use or disuse -on a part, may cause corresponding modifications of the gemmules, -and through these of the part in the succeeding generation. “A more -perplexing problem can hardly be proposed,” and yet it receives an -explanation on this hypothesis. Such causes must, as a rule, act during -many generations before the modification reappears in the offspring. -This may be due to the unaltered gemmules derived from earlier -generations, and their gradual replacement by the increasing number of -altered gemmules. - -Variation in plants is much more frequent in sexually produced than it -is in asexually produced individuals. This may be due to the absence -in the latter of that great cause of variability, changes in the -reproductive organs under altered conditions. Furthermore, the former -alone pass through the earlier phases of development, when structure is -most plastic and yields most readily to the causes inducing variability. - -The stability of hybrids and of many varieties when propagated by buds, -as compared with their reversion to the parent form when propagated by -seed, remains inexplicable. - -Hence variability is explained as due (1) to the irregularity in -number of gemmules, to their transpositions, and redevelopment -when dormant; and (2) to their actual modification and the gradual -replacement by them of unaltered gemmules. - -INHERITANCE.--The non-transmission by heredity of mutilations, even -when repeated for many generations, as in docking the tails of -certain domesticated breeds, may be explained by the persistence of -gemmules from still earlier generations. The cases of inheritance when -mutilations are followed by disease, as in Brown-Séquard’s experiments -on guinea-pigs, may be due to the gemmules being attracted to the -diseased part and there destroyed. - -The disappearance of a rudimentary part, together with its occasional -reappearance by reversion, is to be understood by the existence of -ancestral gemmules, for which the corresponding cells have, except in -the cases of reversion, lost their affinity. When the disappearance is -final and complete, the gemmules have probably perished altogether. - -“Most, or perhaps all, of the secondary characters which appertain to -one sex, lie dormant in the other sex; that is, gemmules capable of -development into the secondary male sexual characters are included -within the female; and conversely female characters in the male.” This -is seen in cases of castration or when the sexual organs from any cause -have become functionless. The sex in which such changes are brought -about tends to develop the secondary sexual characters of the other -sex. The normal development of the secondary characters proper to the -sex of the individual may be explained by a slight difference in the -elective affinity of the cells so that they attract the corresponding -gemmules rather than those of the opposite sex, which as we have seen -are also present. - -The male characters of the male sex are in many species latent except -at certain seasons of the year, and in both sexes the proper characters -are latent until sexual maturity. All such latent characters are -closely connected with the cases of ordinary reversion. The appearance -(whether seasonal or in the course of development) of cells with -affinities for the latent gemmules explains the development of the -characters in question. - -Certain butterflies and plants (_e.g._ Lythrum) produce two or -more separate forms of individuals. In these cases each individual -includes the latent gemmules of the other forms as well as its own. -Hermaphroditism in unisexual species, and especially in the occasional -cases of insects in which the right side of the body is one sex and the -left side the other, the line of separation dividing the individual -into two equal halves, can be explained by slight abnormal changes in -the affinities of cells for gemmules, so that a certain group of cells, -or all the cells on one side of the body, attract the gemmules which -would normally have remained latent. - -Reversion is induced by a change of conditions and especially by -crossing. The first results of crossing are usually intermediate -between the parents, but in the next generation there is commonly -reversion to one or both parent-forms, or even to a more remote -ancestor. The existence of abundant hybridised gemmules is shown by the -propagation of the cross in a true form by means of buds; but dormant -gemmules from the parent-form are also present and multiply. In the -sexual elements of the hybrid there are both pure and hybrid gemmules, -and the addition of the pure gemmules in one sex to those in the other -accounts for the reversion, especially if we assume that pure “gemmules -of the same nature would be especially apt to combine.” Partial -reversion on the one hand, and the reappearance of the hybrid form on -the other, would be respectively due to a combination of pure with -hybrid gemmules, and of the hybrid gemmules from both parent hybrids. - -When characters which do not blend exist in the parents, crossing -may result in an insufficiency of gemmules from the male alone and -from the female alone, and then dormant ancestral gemmules might have -the opportunity of development, and thus cause reversion. Similarly -certain conditions might favour the increase and development of -dormant gemmules. Diseases appearing in alternate generations, or -gaining strength by the intermission of a generation, may be due to -the increase of the gemmules in the intervening time, and the same -explanation may hold for the sudden and irregular increase of a weakly -inherited modification. - -Darwin ends his general conclusions with these words:-- - - “No other attempt, as far as I am aware, has been made, - imperfect as this confessedly is, to connect under one point - of view these several grand classes of facts. An organic - being is a microcosm--a little universe, formed of a host of - self-propagating organisms, inconceivably minute and numerous as - the stars in heaven.” - - - - -CHAPTER XXII. - -PANGENESIS AND CONTINUITY OF THE GERM-PLASM: DARWIN’S CONFIDENCE IN -PANGENESIS. - - -[Sidenote: PANGENESIS.] - -Darwin’s letters prove that he thought very highly of this hypothesis; -and whether the future determine it to be true or erroneous, it must -surely rank as among the greatest of his intellectual efforts. In his -autobiography he says of it:-- - - “An unverified hypothesis is of little or no value; but if any - one should hereafter be led to make observations by which some - such hypothesis could be established, I shall have done good - service, as an astonishing number of isolated facts can be thus - connected together and rendered intelligible.” - -The hypothesis was submitted to Huxley (May 27th, 1865?) in manuscript -and alluded to in the letter sent at the same time. An unfavourable -reply was evidently received, for we find Darwin writing to Huxley, -July 12th (1865?):-- - - “I do not doubt your judgment is perfectly just, and I will try - to persuade myself not to publish. The whole affair is much too - speculative; yet I think some such view will have to be adopted, - when I call to mind such facts as the inherited effects of use - and disuse, &c.” - -This last sentence is of great interest, and the same opinion comes -out strongly in his published account of the hypothesis, viz. the -view that the real facts which imperatively demand some material to -pass from the body-cells to the germ-cells in order to account for -their hereditary transmission are the effects of use and disuse, or the -influence of surroundings--in fact, all those characters which are now -called “acquired.” And it is impossible to escape the conclusion that, -if acquired characters are transmissible by heredity, an hypothesis -which is substantially that of pangenesis will have to be accepted. -Darwin did not doubt this transmission, and he framed pangenesis mainly -to account for it. - -Considerable doubt has of recent years been thrown upon the -transmission of acquired characters, and if hereafter this doubt -be justified, it will be possible to substitute for pangenesis a -hypothesis like the “continuity of the germ-plasm” brought forward by -Professor Weismann. A few words indicating the contrast between the two -hypotheses may not be out of place. - -In Professor Weismann’s hypothesis the germ-plasm contained in the -nucleus of the germ-cell possesses, if placed under right conditions, -the power of developing into an organism. It is not, however, entirely -used up during development, and the part which remains grows and is -stored in the germ-cells of the offspring, and ultimately develops -into the succeeding generation. Hence parent and offspring resemble -each other because they are formed from the same thing. There is no -real break between the generations; they are thrown up successively -from a continuous line of germ-plasm. In this hypothesis the germ -is the essential thing, the body a mere secondary product. It is a -theory of Blastogenesis as contrasted with Pangenesis. The hereditary -transmission of acquired characters, in which many still believe, is -quite irreconcilable with it, and if substantiated would overthrow it -altogether. - -On the other hand the body-cells are the essential elements of -pangenesis, and the germ-cells the mere meeting-places of their -representatives and quite devoid of significance on their own account. -There is some sort of interruption between successive generations, as -the gemmules develop into cells, which again throw off gemmules; the -break, however, is bridged by the ancestral gemmules and by the life of -the body-cell which intervenes between the gemmule from which it arose -and that to which it gives rise. - -The remaining chief occasions on which Darwin alludes to pangenesis in -his published letters are quoted below; they prove his confidence in -the hypothesis and the nature of the hold it had upon his mind. - -Later on he again wrote to Huxley on the same subject:-- - - “I am rather ashamed of the whole affair, but not converted to a - no-belief.... It is all rubbish to speculate as I have done; yet, - if I ever have strength to publish my next book, I fear I shall - not resist ‘Pangenesis,’ but I assure you I will put it humbly - enough. The ordinary course of development of beings, such as the - Echinodermata, in which new organs are formed at quite remote - spots from the analogous previous parts, seems to me extremely - difficult to reconcile on any view except the free diffusion in - the parent of the germs or gemmules of each separate new organ: - and so in cases of alternate generation.” - -_To_ LYELL, _August 22nd, 1867_. - - “I have been particularly pleased that you have noticed - Pangenesis. I do not know whether you ever had the feeling of - having thought so much over a subject that you had lost all power - of judging it. This is my case with Pangenesis (which is 26 or - 27 years old), but I am inclined to think that if it be admitted - as a probable hypothesis it will be a somewhat important step in - Biology.” - -_To_ ASA GRAY, _October 16th, 1867_. - - “The chapter on what I call Pangenesis will be called a mad - dream, and I shall be pretty well satisfied if you think it a - dream worth publishing; but at the bottom of my own mind I think - it contains a great truth.” - -_To_ HOOKER, _November 17th_ [1867]. - - “I shall be intensely anxious to hear what you think about - Pangenesis; though I can see how fearfully imperfect, even in - mere conjectural conclusions, it is; yet it has been an infinite - satisfaction to me somehow to connect the various large groups of - facts, which I have long considered, by an intelligible thread.” - -_To_ FRITZ MÜLLER, _January 30th_ [1868]. - - “... I should very much like to hear what you think of - ‘Pangenesis,’ though I fear it will appear to _every one_ far too - speculative.” - -_To_ HOOKER, _February 23rd_ [1868]. - -After expressing a fear that Pangenesis is still-born because of the -difficulty with which it is understood, he says:-- - - “You will think me very self-sufficient, when I declare that I - feel _sure_ if Pangenesis is now still-born it will, thank God, - at some future time reappear, begotten by some other father, - and christened by some other name. Have you ever met with any - tangible and clear view of what takes place in generation, - whether by seeds or buds, or how a long-lost character can - possibly reappear; or how the male element can possibly affect - the mother plant, or the mother animal, so that her future - progeny are affected? Now all these points and many others are - connected together, whether truly or falsely is another question, - by Pangenesis. You see I die hard, and stick up for my poor - child.” - -_To_ WALLACE, _February 27th_ [1868]. - - “You cannot well imagine how much I have been pleased by what - you say about ‘Pangenesis’.... What you say exactly and fully - expresses my feeling, viz. that it is a relief to have some - feasible explanation of the various facts, which can be given - up as soon as any better hypothesis is found. It has certainly - been an immense relief to my mind; for I have been stumbling over - the subject for years, dimly seeing that some relation existed - between the various classes of facts.... You have indeed pleased - me, for I had given up the great god Pan as a still-born deity.” - -_To_ HOOKER, _February 28th_ [1868]. - - “I see clearly that any satisfaction which Pan may give will - depend on the constitution of each man’s mind.... I heard - yesterday from Wallace, who says (excuse horrid vanity), ‘I can - hardly tell you how much I admire the chapter on “Pangenesis.” It - is a _positive comfort_ to me to have any feasible explanation - of a difficulty that has always been haunting me, and I shall - never be able to give it up till a better one supplies its - place, and that I think hardly possible, &c.’ Now his foregoing - [italicised] words express my sentiments exactly and fully: - though perhaps I feel the relief extra strongly from having - during many years vainly attempted to form some hypothesis. - When you or Huxley say that a single cell of a plant, or stump - of an amputated limb, has the ‘potentiality’ of reproducing - the whole--or ‘diffuses an influence,’ these words give me no - positive idea;--but, when it is said that the cells of a plant, - or stump, include atoms derived from every other cell of the - whole organism and capable of development, I gain a distinct - idea. But this idea would not be worth a rush, if it applied to - one case alone; but it seems to me to apply to all the forms - of reproduction--inheritance--metamorphosis--to the abnormal - transposition of organs--to the direct action of the male - element on the mother plant, &c. Therefore I fully believe that - each cell does _actually_ throw off an atom or gemmule of its - contents;--but whether or not, this hypothesis serves as a useful - connecting link for various grand classes of physiological facts, - which at present stand absolutely isolated.” - -_To_ V. CARUS, _March 21st_ [1868]. - - “... Sir C. Lyell says to every one, ‘You may not believe in - “Pangenesis,” but if you once understand it, you will never get - it out of your mind.’ And with this criticism I am perfectly - content. All cases of inheritance and reversion and development - now appear to me under a new light.” - -_To_ FRITZ MÜLLER, _June, 1868_. - - “I have yet hopes that you will think well of Pangenesis. I feel - sure that our minds are somewhat alike, and I find it a great - relief to have some definite, though hypothetical view, when - I reflect on the wonderful transformations of animals,--the - re-growth of parts,--and especially the direct action of pollen - on the mother-form, &c. It often appears to me almost certain - that the characters of the parents are ‘photographed’ on the - child, only by means of material atoms derived from each cell in - both parents, and developed in the child.” - -_To_ ASA GRAY, _May 8th_ [1868]. - - “Your article in the _Nation_ [March 19th] seems to me very good, - and you give an excellent idea of Pangenesis--an infant cherished - by few as yet, except his tender parent, but which will live a - long life. There is parental presumption for you!” - -_To_ E. RAY LANKESTER, _March 15th_ [1870]. - - “I was pleased to see you refer[L] to my much despised child, - ‘Pangenesis,’ who I think will some day, under some better nurse, - turn out a fine stripling.” - -_To_ WALLACE, _August 28th, 1872_. - - “Notwithstanding all his [Dr. Bastian’s] sneers I do not strike - my colours as yet about Pangenesis.” - -In the second edition of “Animals and Plants,” Beale’s criticism -of the hypothesis is alluded to with characteristic candour and -humour:--“Dr. Lionel Beale (_Nature_, May 11th, 1871, p. 26) sneers -at the whole doctrine with much acerbity and some justice.” Galton’s -paper before the Royal Society (March 30th, 1871), upon the results of -inter-transfusion of blood as destructive of pangenesis, was answered -by Darwin in _Nature_ (April 27th, 1871). He did “not allow that -pangenesis has as yet received its death-blow, though from presenting -so many vulnerable points its life is always in jeopardy.” - -Galton had argued that the gemmules present in the blood of one -individual would be expected to pass into the other individual and to -produce hereditary effects on its offspring. This, however, did not -occur. Romanes repeated these experiments under more rigid conditions, -but with the same negative results; equally negative were the effects -of his transplantation of skin from one animal to another, although the -skin grew quite successfully in its new position. - - - - -CHAPTER XXIII. - -DESCENT OF MAN--EXPRESSION OF EMOTIONS--EARTH-WORMS (1871–81). - - -The work on “The Descent of Man” was begun as soon as Darwin had sent -the manuscript of “Animals and Plants” to the printers, although -notes on the subject had been collected from time to time during the -previous thirty years--in fact, ever since Darwin had come to definite -conclusions on evolution. - -The book was published February 24th, 1871, but, as in the case of -his other publications, continuous work upon the manuscript had been -impossible. The volume attracted great interest, and 5,000 copies were -printed in 1871 in addition to the first 2,500. - -The full title of the book is “The Descent of Man, and Selection in -Relation to Sex,” and, as this title almost implies, it is made up of -two distinct works, which might well have been issued separately. The -first part, dealing with man, is far shorter than the other. Darwin -had from the first considered that his theory of evolution by natural -selection would involve man as well as the other animals, and, that no -one might accuse him of want of candour, he had said in the “Origin” -that by this work “light would be thrown on the origin of man and his -history.” But he was anxious to justify this statement, which was, of -course, distasteful to very many in those days, by a most complete -treatment of the subject. - -[Sidenote: DESCENT OF MAN.] - -He opens this part of the work, which he calls “The Descent or Origin -of Man,” by discussing the structures which are common to man and -animals, including those which are represented in man in a rudimentary -state, and by showing the similarity of the phases through which man -and animals pass during their embryological development. - -Having thus shown that man was probably descended from some lower -form, he considers the mode by which the process was effected, showing -that man possesses variability in body and mind, and is, like other -animals, subject to all the laws of inheritance and variation, and to -the direct action of surrounding conditions, and to the effect of the -use and disuse of parts, and that his rate of increase is such as to -render a large amount of extermination inevitable. In other words, he -presents the same facilities for the operation of natural selection as -those presented by other animals. The points in which man differs from -other animals are then considered in relation to their possible origin -by natural selection. The differences and resemblances between the mind -of man and animals are discussed in much detail, and the origin of the -former through natural selection is defended. This part concludes with -the consideration of the position of man in the animal series, his -birthplace and antiquity, and with an account of the formation of races. - -In the second part Darwin brings forward a large body of evidence in -favour of his hypothesis of sexual selection--viz. the view that, in -the higher animals, some alteration, especially of the secondary sexual -characters, is produced by the preferences and rejections of the sex -which is sought by the other. Such results are commonly found in the -males as a result of the preferences of the females accumulated through -countless generations; but in some species the females court the males, -and are themselves subject to the same process of improvement by -selection. - -Opinion is still divided on this most interesting question. Wallace, -more convinced than ever as to the efficiency and scope of natural -selection, after first doubting, has finally come to reject sexual -selection altogether. Probably the majority of naturalists are -convinced by Darwin’s arguments and his great array of facts that -the principle of sexual selection is real, and accounts for certain -relatively unimportant features in the higher animals, and they further -accept Darwin’s opinion that its action has always been entirely -subordinate to natural selection. - -A brief third part considers sexual selection in relation to man. - -Darwin says, in his “Autobiography,” that sexual selection and “the -variation of our domestic productions, together with the causes and -laws of variation, inheritance, and the intercrossing of plants, are -the sole subjects which I have been able to write about in full, so as -to use all the materials which I have collected.” - -[Sidenote: EXPRESSION OF EMOTIONS.] - -“The Expression of the Emotions,” at first intended as a chapter of the -“Descent,” was begun, only two days after the proofs of the latter had -been corrected, on January 15th, 1871. The book was published in the -autumn of the following year; the edition consisted of 7,000 copies, -and 2,000 were printed at the end of the year; and this, we are told, -was a mistake, as it prevented the appearance of a second edition, with -notes and corrections, during the author’s lifetime. Darwin had begun -to take notes on this subject when his first child was born, December -27th, 1839, for he tells us that, even then, he felt convinced “that -the most complex and fine shades of expression must all have had a -gradual and natural origin.”--(“Autobiography.”) - -In this work Darwin argues with great wealth of illustration and the -record of numberless interesting observations, that the movements of -expression are to be explained by three principles. The first of these -is that movements made in gratifying some desire become by repetition -so habitual that the slightest feeling of desire leads to their -performance, however useless they may then be. The second principle -is that of antithesis--“the habit of voluntarily performing opposite -movements under opposite impulses.” The third principle is “the direct -action of the excited nervous system on the body, independently of the -will, and independently, in large part, of habit.” - -By showing that the expressions of emotions could thus be explained -naturally, Darwin undermined the position taken up by Sir Charles Bell, -that the muscles used in producing expression were created for this -special end. - -In 1876 he re-commenced geological work, bringing out his previous -works on “Volcanic Islands,” and on “South America,” as a single -volume. In this year too he wrote (November 16th) a most interesting -letter to James Geikie, offering an explanation of the large stones -standing in an upright position in the drift of the south of England. -He had noticed the same thing with the flints in the red clay left -upon the chalk as a residuum after the action of solvent agencies -on the latter. This position he explained was due to the movement -following the slow subsidence of parts of the clay as the chalk beneath -dissolved, the flints arranging themselves along the lines of least -resistance. This suggested to him the view that the flints in the drift -are to be explained by the subsidence, during the warmer climate which -followed the glacial period, of alternate layers of snow and drift -accumulated during the winters and summers respectively, of the cold -period itself. - -This interesting view will, Geikie believes, come to be accepted as the -truth. - -[Sidenote: WORK OF EARTH-WORMS.] - -The book upon “The Formation of Vegetable Mould Through the Action -of Worms,” must be included among his geological works, although it -contains a great many observations of deep zoological interest. It -has been stated already that he wrote a paper on this subject for -the Geological Society in 1838. In 1877 he studied the mode by which -Roman remains gain their protective covering of mould; again towards -the end of 1880 he began systematically to prepare the book, which -was published on October 10th of the following year. It was extremely -successful, 8,500 copies being sold in three years. - -This interesting work affords a good illustration of the tremendous -results obtained, even in a moderate time, by an immense number of -workers all using their powers in one direction. Each single earth-worm -swallows earth in the excavation of its burrow and for the nutriment -it contains, the waste material being ejected as “castings” at the -surface, and as a lining to the burrow. But although the amount of -earth thus swallowed by a single worm is not large, worms are so -numerous that “the whole of the superficial mould ... has passed, and -will again pass, every few years through the bodies of worms.” The -result of this unceasing transport of the deeper mould to the surface -is shown to be the burial of stones, either singly or in layers (as in -paths), the covering and consequent protection of ancient buildings, -and the preparation of soil for plants. In addition to this, the -geological denuding agencies are assisted by the manner in which the -deeper soil is brought into a position in which it is exposed to their -action. - -In 1879 he wrote and published a life of his grandfather, Erasmus -Darwin, as “a preliminary notice” to the English translation of E. -Krause’s Life; but Darwin’s contribution forms the larger part of the -volume. - - - - -CHAPTER XXIV. - -BOTANICAL WORKS (1862–86). - - -Darwin’s botanical works are referred to separately, and receive more -systematic treatment than the others, in the great “Life and Letters.” -They form, together with the botanical letters, the subject of the -seventh to the twelfth chapters in the last volume. It will therefore -be unnecessary to treat them in any detail, although they form some of -the most important and interesting of all his biological investigations. - -_Fertilisation of flowers._--“The Fertilisation of Orchids” was the -first published of the botanical works, appearing in 1862, followed -by a second and greatly altered edition in 1877. The object of the -work “is to show that the contrivances by which orchids are fertilised -are as varied and almost as perfect as any of the most beautiful -adaptations in the animal kingdom; and secondly, to show that these -contrivances have for their main object the fertilisation of the -flowers with pollen brought by insects from a distant plant.” Even -in 1837 Darwin had written in his note-book, “Do not plants which -have male and female organs together [_i.e._ in the same flower] yet -receive influence from other plants? Does not Lyell give some argument -about varieties being difficult to keep [true] on account of pollen -from other plants? Because this may be applied to show all plants do -receive intermixture.” (Quoted in the “Life and Letters.”) In 1841, -Robert Brown, the distinguished botanist, advised Darwin to read -Sprengel’s “Secret of Nature Displayed” (Berlin, 1793). The result was -to encourage and assist Darwin in his work on fertilisation of flowers -by insects, and to bring about the first due recognition of Sprengel’s -merits, long after his death. - -“_The Effects of Cross- and Self-fertilisation in the Vegetable -Kingdom._”--This work has a very direct bearing on that last mentioned. -Darwin speaks in the Autobiography “of having come [in 1839] to the -conclusion in my speculations on the origin of species, that crossing -played an important part in keeping specific forms constant.” Later -on he came to see that the advantage of crossing is more direct, -and results from the greater vigour of the offspring over those of -self-fertilised plants. The object of this work, published in 1876, -was to prove this point by experimental evidence of sufficient amount, -and to show in numerous cases, by measurements of height or weight, -or by counting the number of seeds produced, that cross-fertilisation -invariably tends towards the greater vigour of offspring. - -Hence the motive cause for the marvellous adaptations by which -cross-fertilisation is ensured was supplied. - -[Sidenote: FORMS OF FLOWERS.] - -“_Different Forms of Flowers on Plants of the Same Species_” was -published in 1877, and a second edition in 1880. This work, like so -many others, had been largely anticipated by the author’s original -papers to scientific societies, in this case to the Linnean. The papers -were combined, brought up to date, and with the addition of much new -matter constituted the volume. The chief part of the work is concerned -with heterostyled plants, viz. species which bear different kinds of -flowers chiefly distinguished by the lengths of the pistil and stamens. -As many as three different forms occur in Lythrum. In this work it -is shown that each of the forms, although possessing both kinds of -sexual organs, is adapted to be fertilised by the pollen of another -form, and that such offspring are more vigorous than those produced -by fertilisation by the same form. He furthermore showed that the -offspring of “illegitimate” parentage (viz. those which were fertilised -by the same form) possessed, in certain respects, a close resemblance -to hybrids among animals. He remarks in his Autobiography, “No little -discovery of mine ever gave me so much pleasure as the making out the -meaning of heterostyled flowers.” - -In addition to the heterostyled flowers, the other differing forms -borne by the same plants are considered, including the cleistogamic -species, in which minute closed flowers are borne as well as the -ordinary open ones. The former are wanting in the scents and colours -of ordinary flowers, and are specially adapted for self-fertilisation, -and the production of “an abundant supply of seeds with little -expenditure.” - -“_Climbing Plants._”--The subject of this volume was published as a -paper before the Linnean Society in 1864. After being corrected, the -material was brought out as a volume in 1875. Darwin, as he tells us in -the Autobiography, was first led to study the subject by a paper by Asa -Gray, which appeared in 1858 (Proc. Amer. Acad. of Arts and Sciences). -Writing to Asa Gray, August 4th, 1863, he said, “My present hobby-horse -I owe to you, viz. the tendrils.” One of the most interesting results -brought forward in this work is the fact that the upper growing part -of a twining stem bends to one side and then travels slowly round, -between two and three hours being required for each revolution, in the -case of the hop growing in a room and observed at the period of most -active movement. The circle swept at the 27th revolution was 19 inches -in diameter. In the case of this plant the three youngest internodes -(or joints), and never less than two of them, were concerned in the -movement; “by the time the lower one ceased to revolve, the one above -was in full action, with a terminal internode just commencing to move.” -The object of this movement is to strike some object round which -the plant may twine. A much grander example was seen in _Ceropegia -Gardnerii_, in which three long internodes and two short ones swept a -circle over 5 feet in diameter, “at the rate of 32 or 33 inches per -hour, in search of some object round which to twine.” The stem of the -plant is not in the least twisted by this movement. Nearly all of the -great divisions of twining plants, leaf-climbers, and tendril-bearers -“have the same remarkable power of spontaneously revolving.” - -[Sidenote: MOVEMENT IN PLANTS.] - -“_The Power of Movements in Plants_” was published on November 6th, -1880. It embodies a vast amount of work carried on in conjunction with -Francis Darwin. This volume bears a very direct relation to that last -mentioned, as Darwin has explained in his Autobiography:-- - - “In accordance with the principle of evolution it was impossible - to account for climbing plants having been developed in so many - widely different groups unless all kinds of plants possess - some slight power of movement of an analogous kind. This I - proved to be the case; and I was further led to a rather wide - generalisation, viz. that the great and important classes of - movements, excited by light, the attraction of gravity, &c., are - all modified forms of the fundamental movement of circumnutation.” - -An extreme example of circumnutation has already been described in the -revolving movements of the youngest parts of the stem of a twining -plant. - -The work evoked very great interest in this country, but was severely -criticised by certain German botanists. The immense number of new -observations must always have a very high value, whatever be the fate -of the general conclusions, concerning which it may be remarked that -Darwin’s conclusions have often been criticised before, but time has -shown that he was right. - -“_Insectivorous Plants_” was published July 2nd, 1875, but I consider -it last, as the subject stands somewhat apart from the rest of his -botanical works. The subject was suggested to him by noticing the -insects caught by the leaves of the Sun-dew (_Drosera_) near Hartfield. -He then studied in great detail the causes of the movement, and the -sensitiveness of the gland-tipped hairs, finding that a piece of hair -weighing 1/78000 of a grain causes one of them to curve inwards, and -alters “the condition of the contents of every cell in the foot-stalk -of the gland.” - -The greater part of the work deals with the experiments on _Drosera_, -which were extremely numerous and detailed. The remainder treats of -other insectivorous plants, such as Dionæa, Pinguicula, Utricularia, -etc. The methods of capture, the movements of the plants under the -stimulus supplied by the living insect (or other animal), and the -resulting changes in the plant-cells were not the only points studied. -He also investigated the digestive secretion and its action upon the -food absorbed by the leaves. - - - - -CHAPTER XXV. - -LETTERS FROM DARWIN TO PROFESSOR MELDOLA (1871–82). - - -By the kindness of my friend Professor Meldola, and the courtesy of -Mr. Francis Darwin, I am enabled to publish for the first time a -series of letters written by Charles Darwin to the former. The whole -series consists of 33 letters, written between January 28th, 1871, and -February 2nd, 1882, only a few weeks before his death. - -When we remember the immense amount of correspondence with which Darwin -had to cope, the constant attention required by his investigations and -publications, and the state of his health, it is deeply interesting -to read these letters, written with such unfailing courtesy, to a -younger worker in the lines that he had suggested, and who was thereby -stimulated and encouraged to undertake the researches which are now so -well known. - -Reading these letters and remembering the circumstances of the writer, -we can understand how it is that, although ill-health prevented his -presence on occasions at which the younger scientific men are wont -to meet--although he was known to but few of them--nevertheless the -charm of his noble and generous nature was a most potent force in -influencing and attracting men; and it was this, no less than his -epoch-making discoveries, which has made it one of the chief regrets of -many a scientific worker that he never saw Charles Darwin. - -[Sidenote: LETTERS.] - -The correspondence was opened by a letter from Meldola informing Darwin -of a case of hexadactylism in a man at Turnham Green. - - “_Jan. 28 [1871]._ - - “Down. - - “DEAR SIR,--I am much obliged for your kindness in informing me - of the hexadactylous case; but so many have been recorded that I - do not think, except under very special circumstances, it would - be worth your while further to investigate it. - - “With my thanks, yours faithfully and obliged, - - “CH. DARWIN.” - - -The next letter refers to Meldola’s communication to _Nature_ (he -had recently written upon pangenesis and upon sexual selection), -and his work on mimicry, protective resemblance, etc. In the latter -part we meet with an interesting reference to the researches on -cross-fertilisation which are now so famous. - - “_June 9th [1871]._ - - “Down. - - “DEAR SIR,--I am greatly obliged by your note. I have read with - much interest and carefully perused your letter in Nature, and - am looking out for a paper announced for Linn. Soc. Your remarks - shall all be in due time fully considered. With respect to the - separation of the sexes, I have often reflected on the subject; - but there is much difficulty, as it seems to me and as Nageli has - insisted, inasmuch as a strong case can be made out in favour of - the view that with plants at least the sexes were primordially - distinct, then became in many cases united, and in not a few - cases re-separated. I have during the last 5 or 6 years been - making a most laborious series of experiments, by which I shall - be able, I think, to demonstrate the wonderful good derived from - crossing, and I am almost sure but shall not know till the end - of the summer that I shall be able to prove that the good is - precisely of the same kind which the adult individual derives - from _slight_ changes of conditions. - - “With my sincere thanks for your interest in my work, I remain, - dear Sir, Yours very faithfully, - - “CH. DARWIN.” - - -The following letter is of great interest in relation to many problems -of sexual selection, protective resemblance, mimicry, etc.:-- - - “_Jan. 23, 1872._ - - “Down. - - “DEAR SIR--The point to which you refer seems to me a very - difficult one. 1^{st} the comparison of the amount of variability - in itself would be difficult. 2^{ndly} of all characters, - colour seems to be the most variable, as we see in domesticated - productions. (3) I fully agree that selection if long continued - gives fixity to characters. We see the reverse of this in the - great variability of fancy races, now being selected by man. - But to give fixity, selection must be continued for a very long - period: pray consider on this head what I have said in the Origin - about the variability of characters developed in an extraordinary - manner, in comparison with the same characters in allied species. - The selection must also be for a definite object, and not for - anything so vague as beauty, or for the superiority of one male - in its weapons over another male, which can in like manner be - modified. This at least seems to me partly to account for the - general variability of secondary sexual characters. In the case - of mimetic insects, there is another element of doubt, as the - imitated form may be undergoing change which will be followed by - the imitating form. This latter consideration seems to me, as - remarked in my ‘Descent of Man,’ to throw much light on how the - process of imitation first began. - - “I enclose a letter from Fritz Müller which I think is well worth - reading, and which please to return to me. - - “You will see he lays much stress on the difficulty of several - remotely allied forms all imitating some one species. Mr. Wallace - did not think that there was so much weight in this objection - as I do. It is, however, possible that a few species in widely - different groups, before they had diverged much, should have - accidentally resembled, to a certain extent, some one species. - You will also see in this letter a strange speculation, which I - should not dare to publish, about the appreciation of certain - colours being developed in those species which frequently behold - other forms similarly ornamented. I do not feel at all sure that - this view is as incredible as it may at first appear. Similar - ideas have passed through my mind when considering the dull - colours of all the organisms which inhabit dull-coloured regions, - such as Patagonia and the Galapagos Is. I suppose you know Mr. - Riley’s excellent essay on mimicry in the last report on the - noxious insects of Missouri or some such title. - - “I hope your work may be in every way successful. - - “I remain, dear Sir, yours faithfully, - “CHARLES DARWIN.” - - -The next letter deals with mimetic resemblance:-- - - “_Mar. 28, 1872._ - - “Down. - - “DEAR SIR--I thank you for your information on various subjects. - The point to which you allude seems to me very obscure, and I - hardly venture to express an opinion on it. My first impression - is that the colour of an imitating form might be modified to - any extent without any tendency being given to the retention - of ancient structural peculiarities. The difficulty of the - subject seems to me to follow from our complete ignorance of the - causes which have led to the generic differences between the - imitating and imitated forms. The subject however seems worth - investigating. If the imitator habitually lives in company with - the imitated, it would be apt to follow in some respects the same - habits of life, and this perhaps would lead to the retention or - acquirement of some of the same structural characters. - - “I wish you all success in your essay, and remain, dear Sir, - yours very faithfully, - - “CH. DARWIN.” - - -The next very brief letter, acknowledging the receipt of a note, was -written from Down, March 26th, 1873. It contained some sympathetic -remarks upon the progress of Meldola’s work upon Mimicry. In the -succeeding letter, printed below, we find a very definite statement of -opinion as to the _rôle_ of monstrosities in evolution:-- - - “_Aug. 13th_ [1873]. - - “Down. - - “DEAR SIR--I am much obliged for your present which no doubt I - shall find at Down on my return home.... - - “I am sorry to say that I cannot answer your question; nor do - I believe that you could find it anywhere even approximately - answered. It is very difficult or impossible to define what is - meant by a larger variation. Such graduate into monstrosities - or generally injurious variations. I do not myself believe that - these are often or ever taken advantage of under nature. It is a - common occurrence that _abrupt_ and considerable variations are - transmitted in an unaltered state, or not at all transmitted, - to the offspring or to some of them. So it is with tailless or - hornless animals, and with sudden and great changes of colour in - flowers.--I wish I could have given you any answer. - - “Dear Sir, yours very faithfully, - “CH. DARWIN.” - - -The succeeding three letters show Darwin’s scrupulous care as regards -the publication, although with every acknowledgment, of the results -obtained by others. They refer to a letter from Fritz Müller which -he had forwarded to Meldola. The latter had written to ask Darwin’s -permission and advice as to the inclusion of some of F. Müller’s -observations in his most interesting paper, “Entomological Notes -bearing on Evolution” (_Ann. and Mag. Nat. Hist._, 1878, 5th series, -Vol. I. p. 155), which he was then preparing:-- - - “_Sept. 14, 1877._ - - “Down. - - “DEAR SIR--I have some doubts whether Fritz Müller would like - extracts from his letters being published after so long an - interval,--that is if the letter relates to the origin of - mimicry; for he published about a year ago an excellent paper on - this subject. I believe it was in the Jenaische Zeitschrift, but - the paper is out of its proper place in my library and I cannot - find it. If you thought it worth while to send me your copy I - could then judge about the publication of extracts. - - “I fear it is not likely that I shall have anything to - communicate to the Entomological Soc. I quite agree with you - that it is a great pity that our Entomologists should confine - themselves to describing species. - - “Dear Sir, yours faithfully, - “CH. DARWIN.” - - - * * * * * - - “_Sept. 22nd_ [1877]. - - “Down. - - “MY DEAR SIR--I am doubtful whether speculations in a letter - ought to be published, especially after a long interval of time. - Any fact which he states, I feel pretty sure he would not at - all object being used by anyone.--Pray do the best you can.--I - should grieve beyond measure to be accused of a breach of - confidence.--He has lately, as I mentioned, thrown much light on - the first steps in mimicry. - - “With respect to dimorphic Butterflies, those about which I have - read appear at different seasons, and have been the subject of an - _admirable_ essay by Prof. Weismann. It is some little time since - I read the essay and one subject drives another out of my head, - but I think he explains all such cases by the direct inherited - effects of temperature. He tried experiments. If you read - German, I believe I could find Weismann’s essays and lend them to - you. In your present interesting case I really do not know what - to think: it seems rather bold to attribute the 2 coloured forms - to nat. selection, before some advantage can be pointed out.--May - not the female revert in some cases? I do not doubt that the - intermediate form could be eliminated as you suggest. - - “I wish that my opinion could have been of any value.... - - “I remain yours very faithfully, - “CH. DARWIN.” - - -This last letter, with others that followed it, directing Meldola’s -attention to Weismann’s “Studies in the Theory of Descent,” resulted -in the English translation which is so admirably rendered and edited. -Many of the later letters are concerned with the progress of this -publication. The remarks about dimorphic butterflies referred to -Meldola’s observation, that in one of those years in which _Colias -edusa_ was extremely abundant, a whole series of forms had been taken -transitional between the normal orange female and the white variety -_helice_:-- - - “_Sept. 27_ [1877]. - - “Down. - - “MY DEAR SIR,--It is impossible for F. M. [Fritz Müller] to - object to anything which you have said in your very interesting - little essay.--I just allude to Butterflies preferring certain - colours at p. 317 of 2nd Edit^{n.} of the Descent and to the case - of the species of Castnia p. 315 which has ornamented hinder - wings and displays them, whilst 2 other species have plain - hind wings and do not display them. My son, who has charge of - my library, returns home to-night and then we will search for - Weismann. He gives splendid case of caterpillar with coloured - ocelli like true eyes, _and which frightened away birds_. - - “Yours sincerely, - “CH. DARWIN.” - - -The reference in this letter is to Meldola’s paper, “Entomological -Notes bearing on Evolution,” soon afterwards published in the _Annals -and Magazine of Natural History_, 1878, Vol. I. p. 155. The caterpillar -referred to is the well-known larva of the Large Elephant Hawk Moth -(_Chærocampa elpenor_). - -Darwin then wrote a brief note (October 19th, 1877) referring to a -number of _Kosmos_ containing an article on “Sexual Selection.” He -offered to send the number if it would interest his correspondent. The -number was sent, as the succeeding letter shows:-- - - “_Oct. 22nd [1877]._ - - “Down. - - “MY DEAR SIR,--I send Kosmos by this post.... - - “Prof. Weismann’s address is Freiburg.--I should think he - would be glad of translation, and would probably arrange for - stereotypes of Plates.--You could say as an introduction that I - had lent you his book.--To find a publisher will be perhaps a - difficulty. Should it be translated I must beg you to get another - copy, as I cannot spare mine for such a length of time.--Wallace - sent me his article and I was quite dissatisfied with it.--To - explain a peacock’s tail by vital activity seems to me mere - verbiage--a mere metaphysical principle. - - “My dear Sir, yours faithfully, - “CH. DARWIN. - - “It will be a public benefit to bring out a translation.” - -Then followed three letters, January 3rd, March 24th, and March 27th, -1878; the first written when Darwin was sending another number of -_Kosmos_, the second when sending his photograph, the third enclosing a -letter from Fritz Müller containing some very interesting observations -on mimicry in South American butterflies. - -He then wrote as follows:-- - - “_April 17/78._ - - “Down. - - “MY DEAR SIR,--I should be very much obliged if you could get - some one to name the photographs of the enclosed insect and read - the enclosed letter. It seems a pretty, but I think not new - case of protective resemblance. One might fancy that the large - ocelli on the under wings were a sexual ornament.--Perhaps these - photographs might be worth exhibiting at the Entomolog. Soc.--I - do not want them returned (unless indeed Dr. Zacharias wants them - back, which is not probable) or the enclosed letter. - - “A single word with the name of the genus and if possible of the - species, would suffice.-- - - “Pray forgive my troubling you and believe me - - “Yours faithfully, - “CH. DARWIN. - - “I am glad that F. Müller’s letter interested you. He has - published a paper with plates on the shape of the hairs or scales - on the odoriferous glands of many butterflies, which I could send - you, but I doubt whether you would care for it.” - -Darwin then sent another letter from Fritz Müller containing some -interesting notes on odoriferous organs in butterflies, and on the -occasional failure of the female insect to deposit her eggs on a plant -which can serve as the food of the young larvæ. The beetles alluded to -were a species of _Spermophagus_. The two letters printed below refer -to the same subjects:-- - - “_May 15 [1878]._ - - “Down. - - “MY DEAR SIR,--I think the enclosed will interest you.--The - letter to me need not be returned as I have had the only - important passage for my work copied out.--In the letter F. M. - [Fritz Müller] sent me seeds of _Cassia neglecta_ and several - beetles arrived alive, having formed their cocoons, and gnawed - their way out of the little peas or seeds.--These elegant - beetles, with the knowledge of their manner of development may - interest some Coleopterist. - - “I hope to hear some time about Dr. Zacharias’ photographs. I - received your obliging letter from Paris. - - “Yours sincerely, - “CH. DARWIN.” - - - * * * * * - - “_May 25 [1878]._ - - “Down. - - “MY DEAR SIR,--The living beetles and the cocoons were found in - a small paper packet containing the seeds. Those from which the - beetles had emerged were much broken, and the larvæ had evidently - attacked some of the other seeds. I am sorry to say that some of - the injured ones were thrown away. I am glad that you are going - to draw up a paper from Fritz Müller’s letters. - - “Yours sincerely, - “CH. DARWIN.” - - -After another short note, dated July 24th, 1878, Darwin wrote the -following letter, which explains how it was that he came to write the -preface to the translation of Weismann’s “Studies”:-- - - “_October 31 [1878]._ - - “Down. - - “MY DEAR SIR,--As you are inclined to be so very liberal as to - have a translation made of Weismann’s Essays on your own risk, - I feel bound to aid you to the small extent of writing a short - prefatory notice. But this is a kind of job, which I do not - feel that I can do at all well and therefore do not like; but I - will do my best. It must, however, be short for I am at present - working very hard. I do not quite understand whether you intend - asking some Publisher to bring out the book on commission at - your cost for if so there will be no difficulty in finding a - Publisher. But if you expect any Publisher to publish at his - risk and cost; I think from recent experience you will have - much difficulty in finding one.--I suppose that you have asked - Weismann’s concurrence. - - “Down is rather an awkward place to reach, as we are 4 miles - from nearest station, Orpington. But I shall be in London for a - week on Nov^r 17th or 18th and could see you then at any time, - and perhaps you could come to luncheon. - - “But if you would prefer to come here, I shall be very happy - to see you either Saturday or Sunday, if you would let me know - hour.--I am, however, bound to tell you that my health is always - doubtful, and that my head does not allow me to converse long - with anyone. - - “With the most cordial sympathy in your undertaking, I remain, my - dear Sir, yours very faithfully, - - “CH. DARWIN.” - - -In November, 1878, Darwin was in London, staying at his daughter’s -house at 4, Bryanston Street. On the 19th he wrote asking Meldola to -lunch to talk over the proposed English edition of Weismann, and on the -25th sent the MS. of the Preface with the following letter:-- - - - “4 Bryanston St., - “Portman Sq^{re}. - - “_Nov. 25_ [1878]. - - “MY DEAR SIR,--I send my little Preface, which I do not at all - like, but which I cannot improve. I should like hereafter to - see it in type. Mr. Bates tells me that Hardwick and Bohn of - Piccadilly intend to go in for publishing solid books; and if - your present publisher should change his mind: Mr. Bohn might be - worth applying to. - - “Yours sincerely, - “CH. DARWIN.” - -Professor Meldola then wrote, suggesting that Darwin should, in his -Preface, point out, by references to the “Origin of Species” and his -other writings, how far he had already traced out the lines which -Weismann had pursued in his researches. The suggestion was made because -in a great many of the Continental writings upon the theory of descent -a number of the points which had been clearly foreshadowed, and in -some cases even explicitly stated, by Darwin had been independently -rediscovered and published as though original. In the editorial notes -to Meldola’s translation full justice to Darwin has been done in this -respect. Darwin’s characteristic reply is deeply interesting. - - “_Nov 26^{th}_ [1878]. - - “4 Bryanston St. - - “MY DEAR SIR,--I am very sorry to say that I cannot agree to your - suggestion.--An author is never a fit judge of his own work, and - I should dislike extremely pointing out when and how Weismann’s - conclusions and work, agreed with my own.--I feel sure that I - ought not to do this, and it would be to me an intolerable task. - Nor does it seem to me the proper office of the Preface, which - is to show what the book contains and that the contents appear - to me valuable. But I can see no objection for you, if you think - fit, to write an introduction with remarks or criticisms of any - kind. Of course I would be glad to advise you on any point as far - as lay in my power, but as a whole I could have nothing to do - with it, on the grounds above specified that an author cannot and - ought not to attempt to judge his own works or compare them with - others. I am sorry to refuse to do anything which you wish.-- - - “We return home early to-morrow morning.--Your green silk seems - to me a splendid colour, whatever the æsthetics may say.--My dear - Sir, yours faithfully, - - “CH. DARWIN.” - - -The “green silk” referred to some specimens of coal-tar colours sent -to show Darwin what modern chemistry had been able to accomplish in -the way of artificial colouring matters. They were at that time of -particular interest in connection with a discussion which had arisen -in Bryanston Street about the so-called “æsthetic” school, which -had become rather predominant at the period, and which affected an -abhorrence of all brilliant colouring, in spite of the circumstance -that nature abounds in the most gorgeous hues, especially in the -tropics. - -The next letter refers to the adoption of the word “phyletic” in the -translation of Weismann. - - “_Dec. 14_ [1878]. - - “Down. - - “MY DEAR SIR,--I am very glad that you are making good progress - with the book.--You could not apply to a worse person than myself - on any philological question. I presume that ‘phyletische’ has - been adopted or modified from Häckel. As the latter uses the - word, it has nearly the sense of genealogical. It always applies - to the lines of descent, and therefore differs somewhat from - ‘innate’; for an inherited character, though derived from the - father alone or only a single generation, would be innate in the - child. I should think ‘phyletic’ would do very well, if you gave - the German word and an explanation, in a foot-note. - - “There has been a delay in answering your letter, but I have just - heard from my son who is away from home, and he says that he is - sorry but he cannot well spare the time to lecture. - - “My dear Sir, yours very faithfully, - “CH. DARWIN.” - - -Then followed two letters (January 20th, and February 7th, 1879), the -first written when Darwin was sending a number of _Kosmos_; the second -referring to it and other papers, and asking that his name should be -put down as a subscriber to the forthcoming translation of Weismann. - -Later on the number of _Kosmos_ for May, 1879, was sent, containing -(p. 100) Fritz Müller’s paper “_Ituna_ and _Thyridia_.” This paper, -although it did not attract sufficient attention at the time, was of -the highest importance in relation to the theory of mimicry, as Meldola -at once perceived. - -Bates in his epoch-making paper in the Transactions of the Linnean -Society (Vol. XXIII. 1862) had founded the theory of mimicry. -Those rarer forms which have diverged from their near allies and, -in superficial appearance, approached some distantly related, but -abundant, species inhabiting the same tract have been, according to -Bates’s theory, benefiting themselves in the struggle for existence. -The mimicked species are, he suggested, abundant because they possess -some special means of protection, such as an unpleasant taste or smell, -and they have an unpleasant reputation which greatly aids them in the -struggle for life; while the mimicking species, by their superficial -resemblance, are enabled to live upon that reputation without -possessing the special means of defence. - -Certain facts well-known to Bates, and brought forward in his paper, -were not explicable by this theory, viz. the resemblance that -often exists between the abundant and specially protected species -themselves. Although a few tentative suggestions were made, such as the -production of a common appearance by similarity of climate, or food, -etc., these facts remained an unexplained mystery until this paper -of Fritz Müller’s in the May number of _Kosmos_. He there suggests -that the mutual resemblance between the specially protected forms is -advantageous, in reducing for each of them the number of individuals -which must be sacrificed during the process of education which their -youthful enemies must undergo, before they learn what is fit and what -unfit for food. The arrangement is, in fact, much like that between a -couple of firms that issue a common advertisement, and so save about -half the expense of advertising alone. It is only another added to the -numerous examples of the production by natural selection, and without -the introduction of consciousness, of a result which could not be -bettered by the deliberate action of the most acute intelligence. - -Meldola at once wrote to Darwin asking his advice about the translation -of F. Müller’s paper, and received the following reply:-- - - “_June 6th, 1879._ - - “Down. - - “MY DEAR MR. MELDOLA,--Your best plan will be to write to ‘Dr. - Ernst Krause, Friedenstrasse, 10 II. Berlin.’ He is one of the - editors with whom I have corresponded. You can say that I sent - you the Journal and called your attention to the paper, but I - cannot take the liberty of advising the supply of clichés. He is - a very obliging man. Had you not better ask for permission to - translate, saying the source will be fully acknowledged? - - “F. Müller’s view of the mutual protection was quite new to me. - - “Yours sincerely, - “CH. DARWIN.” - - -The clichés were obtained and Meldola’s translation published in the -Proceedings of the Entomological Society for 1879, p. 20. The new -contribution to the theory of mimicry was at first somewhat severely -criticised, even Bates being adverse to it. Subsequent work has -abundantly justified it as by far the most important addition to the -subject since Bates’s original paper. In fact, many cases which have -been up to the present explained under the theory of true (Batesian) -mimicry are now believed to come under that which we owe to F. -Müller--viz. convergence between specially protected forms for mutual -benefit. - -An interesting paper by Dr. F. A. Dixey, published in the Transactions -of the Entomological Society for the present year (1896), contains -convincing arguments in favour of this view as regards some of the -_Pieridæ_ of South America in relation to the _Heliconidæ_ and -_Papilionidæ_ which they resemble. - -It is of the highest interest to learn that the first introduction -of this new and most suggestive hypothesis into this country was due -to the direct influence of Darwin himself, who brought it before the -notice of the one man who was likely to appreciate it at its true value -and to find the means for its presentation to English naturalists. - -In the next year Meldola wished to translate further papers of Fritz -Müller’s, and received the following letter on the subject:-- - - “_Nov. 25/80._ - - “Down. - - “MY DEAR SIR,--I can well believe that your labour must have been - great, and everyone is bound to aid you in any way. - - “No. I. of F. Müller’s paper is in the August no. for 1877. - - “No. II.--is in the October no. for 1877. - - “Both these articles I remember thinking excellent. - - “I am not one of the editors of Kosmos, only a kind of patron(!) - and therefore cannot give permission; but when you write to the - editors you can say that I have expressed a hope that permission - would be granted, you acknowledging source of papers. - - “Heartily wishing you success and in haste to catch first post, I - remain yours very faithfully, - - “CH. DARWIN.” - - -Shortly after the date of the last letter Professor Meldola came across -a copy of Thomson’s “Annals of Philosophy” on a bookstall. It bore the -name “Erasmus Darwin” on the first page, and Meldola offered it to -Charles Darwin, thinking it might have belonged to his grandfather. - - “_March 12th, 1881_ [The date was evidently May, and not March]. - - “Down. - - “DEAR MR. MELDOLA,--It is very kind of you to offer to send me - the book, but I feel sure that it could not have belonged to - my grandfather.--My eldest brother’s name is Erasmus and he - attended to chemistry when young, and I suppose that the ‘Annals - of Philosophy’ was left at my Father’s house and sold with the - Library which belonged to my sisters.--I will look to the few - words of Preface to Wiesmann [_sic_], whenever I receive a - proof.--With many thanks.-- - - “Yours very faithfully, - “CH. DARWIN.” - - -Then followed a brief note dated “Aug. 8, 1881,” referring to some -point in the work upon which Meldola was then engaged, and which cannot -now be ascertained. Another letter of the same date referred to the -translation of Weismann, and contained some encouraging words upon the -interest created by the work and upon the success of the Essex Field -Club, in which Meldola had taken a leading part. Another brief note of -August 10th, 1881, apparently refers to some paper which cannot now be -identified. - -The following interesting letter is of uncertain date:-- - - “_? 19th, ? 1881._ - - “Down. - - “DEAR MR. MELDOLA,--When I read the F. M. [Fritz Müller] paper - your doubt occurred to me and I must say this, I would rather - have expected that the knowledge of distasteful caterpillars - would have been inherited, but I distinctly remember an account - (when Wallace first propounded his warning colors) published of - some birds, I think turkeys, being experimented upon and they - shook their heads after trying some caterpillars as if they had a - horrid taste in their mouths. I fancied this thing was published - by Mr. Weir or could it have been by Mr. Butler? It would be well - to look in Mr. Belt’s ‘Nicaragua’ as he tried some experiments. I - am not sure that there is not some statement of the kind in it. - - “Yours faithfully, - “CHARLES DARWIN. - - “I daresay Mr. Wallace or Bates would remember the statement of - some birds shaking their heads to which I refer.” - -The statement about the turkeys evidently refers to Stainton’s -experiment with young birds of this kind, which immediately devoured -numerous protectively coloured moths, but, after seizing, invariably -rejected, a conspicuous white species (_Spilosoma menthastri_). It was -Belt’s ducks which shook their heads after tasting a very conspicuous -Nicaraguan frog. Darwin wished to show by this evidence that there was -no instinctive knowledge such as would have saved the birds from an -evidently unpleasant experience. - -The last letter, deeply interesting both on its own account and because -it was written so near the end of Darwin’s life, was a reply to one -from Meldola in which he had said that the publishers were complaining -that the list of subscribers was disappointing, and that they had -expressed the wish that Mr. Darwin could see his way to writing a much -longer introductory notice than he had done. - - “_Feb. 2nd [1882]._ - - “Down. - - “DEAR MR. MELDOLA,--I am very sorry that I can add nothing to - my very brief notice without reading again Weismann’s work and - getting up the whole subject by reading my own and other books, - and for so much labour I have not strength. I have now been - working at other subjects for some years, and when a man grows - as old as I am, it is a great wrench to his brain to go back to - old and half-forgotten subjects. You would not readily believe - how often I am asked questions of all kinds, and quite lately I - have had to give up much time to do a work, not at all concerning - myself, but which I did not like to refuse. I must however - somewhere draw the line, or my life will be a misery to me. - - “I have read your Preface and it seems to me _excellent_. I - am sorry in many ways, including the honour of England as a - scientific country, that your translation has as yet sold badly. - Does the publisher or do you lose by it? If the publisher, though - I should be sorry for him, yet it is in the way of business; but - if you yourself lose by it, I earnestly beg you to allow me to - subscribe a trifle, viz. ten guineas, towards the expense of this - work, which you have undertaken on public grounds. - - “Pray believe me, yours very faithfully, - “CH. DARWIN.” - - -Darwin’s generous offer, although gratefully declined, was a warm -encouragement in the laborious, and in some respects thankless, task of -translator and editor--a task which, in the case of the English edition -of Weismann’s “Studies in the Theory of Descent,” was carried out in so -admirable a manner. - - - - -CHAPTER XXVI. - -HIS LAST ILLNESS (1882). - - -In the last few months of his life, towards the end of 1881 and -beginning of 1882, Darwin began to suffer from his heart, causing -attacks of pain and faintness which increased in number. On March 7th, -1882, he had one of these seizures when walking, “and this was the last -time that he was able to reach his favourite ‘sand-walk’” (“Life and -Letters”). After this he became rather better, and on April 17th was -able to record the progress of an experiment for his son Francis. The -following sentences are quoted from the “Life and Letters”:-- - - “During the night of April 18th, about a quarter to twelve, he - had a severe attack and passed into a faint, from which he was - brought back to consciousness with very great difficulty. He - seemed to recognise the approach of death, and said, ‘I am not - the least afraid to die.’ All the next morning he suffered from - terrible nausea and faintness, and hardly rallied before the end - came. - - “He died at about four o’clock on Wednesday, April 19th, 1882.” - -He was buried in Westminster Abbey on April 26th. - -Thus died one of the greatest of men, after a life of patient and -continuous work interrupted only by ill-health; a man who was, perhaps, -more widely attacked and more grossly misrepresented than any other, -but who lived to see his teachings almost universally received; a -man whose quiet, peaceful life of work, and whose precarious health, -prevented that large intercourse with his fellow-men which is generally -forced upon greatness, but who was so beloved by his circle of intimate -friends that, through their contagious enthusiasm, and through the -glimpses of his nature revealed in his writings, he was in all -likelihood more greatly loved than any other man of his time by those -who knew him not. - -And for all those of us who have loved Darwin, although we have never -seen him, we can at any rate remember that we have lived in his time -and have heard the echoes of his living voice; he has been even more -to us than he will be to future generations of mankind--a mighty -tradition, gaining rather than losing in force and in overwhelming -interest as each passing age, inspired by his example, guided by his -teachings, adds to the knowledge of nature, and in so doing gives an -ever deeper meaning to his life and work. - - - - -FOOTNOTES - - -[A] See Professor Meldola’s interesting Presidential Address to the -Entomological Society of London (January, 1896) on the use of the -imagination in science, printed in the Transactions of the Society and -in _Nature_. See also “The Advancement of Science” (London, 1890), in -which Professor Lankester maintains (p. 4): “All true science deals -with speculation and hypothesis, and acknowledges as its most valued -servant--its indispensable ally and helpmeet--that which our German -friends call ‘Phantasie’ and we ‘the Imagination.’” Consult also -Professor Tyndall’s essay “On the Scientific Use of the Imagination” -(“Fragments of Science,” 1889, vol. ii., p. 101). - -[B] We are told in the “Life and Letters” that the last proof of the -“Journal” was finished in 1837. The Diary, as stated above, was written -between July, 1837, and February, 1838. - -[C] Professor H. F. Osborn has rightly urged that this essay should be -published (“From the Greeks to Darwin,” 1894, p. 235). - -[D] My friend Mr. J. J. Walker, R.N., tells me that the house in which -Wallace lived in Ternate, and in which the essay was written, is still -pointed out by the natives as one of the features of the place. It is, -unfortunately, much dilapidated. - -[E] Wallace has added the following note to the reprint in “Natural -Selection and Tropical Nature,” London, 1891, p. 31: “That is, they -will vary, and the variations which tend to adapt them to the wild -state, and therefore approximate them to wild animals, will be -preserved. Those individuals which do not vary sufficiently will -perish.” - -[F] Since the above paragraph was written I have again read Professor -Newton’s eloquent Address to the Biological Section of the British -Association at Manchester in 1887, and find that he says on the -same subject--“If in future you should meet with any cynic who may -point the finger of scorn at the petty quarrels in which naturalists -unfortunately at times engage, particularly in regard to the priority -of their discoveries, you can always refer him to this greatest of all -cases, where scientific rivalry not only did not interfere with, but -even strengthened, the good-feeling which existed between two of the -most original investigators” (Report of Meeting, p. 731). - -[G] “There is grandeur in this view of life, with its several powers, -having been originally breathed by the Creator into a few forms or into -one;...”--(Concluding paragraph of “Origin,” 1860, p. 490.) - -[H] “Life of Lord Sherbrooke,” Vol. II. (pp. 205–206), Longmans & Co. -London, 1893. - -[I] Proc. Roy. Soc. Edin., Jan. 16th, 1860. - -[J] Presidential address to the British Association at Belfast, 1874. -Report, p. lxxxvii. - -[K] See H. F. Osborn, “From the Greeks to Darwin” (1894). - -[L] In “Comparative Longevity.” - - - - -INDEX. - - - Abnormal Transposition, or Multiplication of Parts, 172 - - Acquired Characters, Transmission of, 179, 180 - - Agassiz, Prof. L., and Darwin, 157, 158 - - Animals, Variation of, under Domestication, 75, 115, 161, _et seq._; - Abnormal Transposition or Multiplication of Parts, 172; - Instinctive Knowledge in, denied, 216 - - Argyll, Duke of, on Natural Selection, 144 - - Atlantis Hypothesis, The, Darwin’s Objections to, 53–55 - - - Bastian, Dr. H. C., 160 - - Bates on Mimicry, 212 - - Bateson on Speculation and Hypothesis in Science, 14–15 - - “Beagle,” Darwin’s Voyage in the, 21–24; - Important Observations and Discoveries, 23; - Countries and Islands visited, 23–24; - Completion of “A Naturalist’s Voyage,” 30; - Zoology of, 31; - Geology of, 35 - - Beale, Dr. Lionel, 184 - - Bear and Whale, a Hypothetical Illustration of Natural Selection, 151 - - Beetles, Wingless, 51 - - Birds, Experimenting with Distasteful Caterpillars, &c., 216 - - Botanical Works of Darwin, 193, _et seq._ - - Bree, Dr., “Species not Transmutable,” 149 - - Butler, Dr., School at Shrewsbury, Darwin’s Education at, 16, 17 - - Butterflies, Dimorphic, 204, 205 - - - Cambridge, Darwin studying at, 18–20; - Revisited, 25 - - Carpenter, Dr., 159 - - Carus, V., 183 - - Case, Mr., Darwin attends his School at Shrewsbury, 16 - - “Challenger” Expedition, The, 53, 55 - - Cirripedia, Monographs on the, 36 - - Climbing Plants, 196; - Revolution of the Upper Part, 196 - - Copley Medal of the Royal Society awarded to Charles Darwin, 109; - to Sir Joseph Hooker, 111 - - Coral Reefs, Work upon the, 32; - Theory of Origin, 33; - Dr. John Murray rejects the Darwinian Theory, 33 - - Creative Hypothesis, Huxley on the, 135 - - Crossing in Plants, The Advantages of, 194 - - Cross-fertilisation in Plants, 201 - - - Darwin, Charles, Birthplace, 9; - His Parentage, 10; - Family Genius, 10; - Secret of his Strength, 13–15; - his high Valuation of Hypothesis, 14; - Boyhood, 16–17; - School-life, 16; - Love of Sport, 16; - at Edinburgh, 17; - Dislike of Dissection, 17; - First Scientific Discovery and Paper, 17, 18; - at Cambridge, 18–20; - his Friendship with Professors Henslow and Sedgwick, 19; - Voyage of the “Beagle,” 21, _et seq._; - Preparation for and Effects of the Voyage, 22; - the Most Important Discoveries during, 23; - Places Visited, 23, 24; - Re-visits Cambridge, 25; - Work upon the Collections, and the “Naturalist’s Voyage,” 25; - at London, 25; - Origin of Species, 25–29; - Geological Work, 29, 33; - Completion of “A Naturalist’s Voyage,” 30; - Zoology of the Voyage of the “Beagle,” 31; - Papers on Earth-Worms, 31; - Marriage, 32; - Book on the Coral Reefs, 32; - Ill-health, 32; - at Down, 35; - his Career as a Biologist, 37; - Systematic Work, 37; - his Dislike of Species-mongers, 39, 40; - Death of his Father and Daughter, 41; - Growth of the Origin of Species Theory, 42–59; - Correspondence with Friends, 50–59; - Experiments with Seeds in Salt Water, 51, 52; - Letter to Wedgwood, 52; - Objections to the Atlantis Hypothesis, 53, 55; - Letter to Lyell, 53; - Friendship and Correspondence with Wallace, 60–64, 81–86; - their Joint Papers Presented to the Linnean Society, 46, 62; - Letter to Asa Gray on Selection, 68–70; - Comparison and Reception of the Joint Papers, 78–82; - Delay in Publishing his Discoveries, 90; - Preparation of Origin of Species, 95, _et seq._; - Observations, 96; - Appeals to Lyell, 97; - Letter to John Murray, 97; - his Influence upon Lyell, 105; - Receives the Copley Medal of the Royal Society, 109; - his Indebtedness to Lyell’s Teaching, 110; - Influence upon Hooker and Asa Gray, 111; - his Controversy with Asa Gray, 114–118; - his Influence upon Huxley, 119–143; - his Views of Natural Selection as the Cause of Evolution not - accepted by Huxley, 121–128; - Extracts from Letters showing Difficulty with which Natural - Selection was Understood, 145, _et seq._; - on Spontaneous Generation, 108, 159; - and Bastian, 160; - his Later Works, 161; - his Theory of Pangenesis, 163, _et seq._; - Variation of Animals and Plants under Domestication, Outline of the - Book, 163; - on Sexual and Asexual Reproductions, 164, _et seq._; - Extracts from Letters to Friends on Pangenesis, 178, _et seq._; - “The Descent of Man,” 186; - “The Expression of the Emotions,” 189; - “Volcanic Islands,” 190; - “South America,” 190; - “The Formation of Vegetable Mould through the Action of Worms,” 191; - his Life of Erasmus Darwin, 192; - “Fertilisation of Orchids,” 193; - Cross- and Self-Fertilisation in the Vegetable Kingdom, 194; - Different Forms of Flowers on Plants of Same Species, 194; - Climbing Plants, 196; - “Power of Movement in Plants,” 197; - “Insectivorous Plants,” 198; - Letters to Prof. Meldola, 199, _et seq._; - his Last Illness, 219; - and Death, 220 - - Darwin, Erasmus, Brother of Charles, 11 - - Darwin, Erasmus, Grandfather of Charles, 10, 192 - - Darwin, Prof. George, Brother of Charles, 11 - - Darwin, Robert Waring, Father of Charles, 10; - Profession and Character, 10; - his Dislike to the “Beagle” Expedition, 21–22; - Death of, 41 - - Darwin Medal of the Royal Society awarded to Huxley, The, 140 - - Darwinism not Evolution, Huxley’s Speeches, 139–141 - - Deposits, Oceanic, 55 - - Descent of Man, The, 186 - - Development, 166, 171 - - Dixey, Dr. F. A., Paper on Mimicry, 214 - - Domestication, Variation by, of Animals and Plants, 115, 161, _et - seq._; - of Animals, 75 - - Down, Darwin’s Home at, 35 - - Drosera and Other Insectivorous Plants, 198 - - - Earthworms, 191; - Castings of, 191; - Papers on the, 31 - - Edinburgh, Darwin studying for Medicine at, 17 - - “Emotions, The Expression of the,” 189, 190 - - Evolution, First Recorded Thoughts upon, 28; - Natural Selection as a Cause not accepted by Huxley, 121, _et seq._; - the Argument for, 100; - supported by Huxley, 121; - Huxley agrees with Darwin, 121, _et seq._; - Discussion at Meeting of the British Association, 82, 138; - not Darwinism, 139–141 - - “Expression of the Emotions, The,” 189, 190 - - Extinction, 43–45 - - - Fertilisation of Germ Cells, 165; - “of Orchids, The,” 193; - of Flowers by Insects, 193; - Effects of Cross- and Self-, 194 - - Fitzroy, Capt., of the “Beagle,” 21, 22 - - Flowers, The Fertilisation of, by Insects, 193; - Effects of Cross- and Self-Fertilisation compared, 194; - Different Forms on the same Plant, 195 - - Flustra, Darwin’s Discovery of the Free-Swimming Larvæ of, 18 - - Forbes, Edward, and the Atlantis Hypothesis, 53 - - “Formation of Vegetable Mould through the Action of Worms, The,” 191 - - Fox, W. Darwin, 19 - - - Galapagos Archipelago, The Animals, etc., of the, 26, 27, 42 - - Galton, F., 184 - - Geikie, James, 190 - - Geological Society, The, Darwin appointed Secretary, 29; - Papers on the Earthworms, 31 - - Geology of the Voyage of the “Beagle,” 35 - - Glacial Phenomena, Darwin’s Paper upon, 33 - - Graft-Hybrids, 166 - - Grafting, Production of Hybrids by, 168 - - Gray, Asa, Darwin’s Correspondence with, 51, 55, 107, 181, 184; - his Influence upon, 112; - Darwin’s Controversy with, 114–118 - - Gray, Dr., 146, 149 - - - Henslow, Prof., Friendship with Darwin, 18–21 - - Herbert, J. M., on Darwin’s Character, 19, 20 - - Hereditary Genius, Evidences in the Darwin Family, 10, 11 - - Heredity, Theories of, 167, 174 - - Hermaphroditism, 175 - - Holmes, Dr. Oliver Wendell, his References to Darwin, 9; - his Correction of Darwin, 9 - - Hooker, Sir Joseph, 37, 48; - Darwin’s Letters to, on Species-mongers, 39–40; - Darwin’s Opinion of, 48; - Friendship and Correspondence with Darwin, 50; - Lyell’s Correspondence with, as to Specific Centres, 57; - Darwin’s Influence upon, 110, _et seq._; - awarded the Copley Medal of the Royal Society, 111; - and Darwin, 146; - Darwin Writing on Pangenesis, 181, 182 - - Huxley, Prof., Criticisms of Darwin’s Theory, 46, 48; - on Teleology, 113; - Darwin’s Influence upon, 119–143; - agrees with Darwin on Evolution, 121; - Views on Natural Selection, 121, 124, 126, 138; - Article in the _Times_ on the Origin of Species, 124; - his Article in the _Westminster Review_, 125; - Lectures on the Causes of the Phenomena of Organic Nature, 128, 142; - Views as to Natural Selection not changed, 137, 138; - Speech at the British Association Meeting at Oxford, 139; - awarded the Darwin Medal of the Royal Society, 140; - Darwinism, not Evolution, 140, 141; - and the Bishop of Oxford, 155 - - Hybrid Grafts, 166 - - Hybridism, 175, 176 - - Hybrids, Tendency to Resemble one Parent, 171; - Sterility of, 171; - Produced by Grafting, 168 - - Hypothesis and Speculation, Bearing on Science, 14, 15 - - - Inheritance, The Theories of, 167, 174 - - Insectivorous Plants, 198 - - Instinctive Knowledge in Animals denied by Darwin, 216 - - - Jenkin, Fleming, 81 - - - Lamarck’s Theory of Evolution, 99; - Comparison with Darwin’s, 148, 150 - - Lankester, Prof. E. Ray, 99, 184 - - Linnean Society, Joint Memoirs by Darwin and Wallace, read before, - 65, _et seq._ - - Lowe, Robert, 150 - - Lyell, Sir Charles, Influence on Darwin, 29, 30, 51; - and Continental Extensions, 53; - and Hooker’s Agreement on the Specific Centres Theory, 57; - Darwin’s Appeal to, on the Natural Selection, 97; - Influence of Darwin upon, 105; - Accepts Darwin’s Views, 108, 109; - Death of, 109; - Darwin’s Letter on Pangenesis, 181 - - Lythrum, Different Forms of Flowers on the, 195 - - - Macleay, W. S., 150 - - Malthus on Population, its Influence on Darwin, 46; - and on Wallace, 88, 89 - - Man, The Descent of, 186 - - Meldola, Prof., on Systematic Work, 37; - and Darwin, 199, _et seq._ - - Metamorphosis, 171 - - Mimetic Resemblance, 202 - - Mimicry, 202, 204; - Bates’ Theory, 212; - Fritz Müller’s Theory, 212; - Dixey’s paper on, 214 - - Müller, Fritz, Darwin’s Letters to, 181, 183; - on Mimicry, 212–214; - his Paper Translated, 213 - - Murray, Andrew, 152 - - Murray, Dr. John, Controversy as to the Origin of Coral Reefs, 33 - - - Naming of Species, Darwin on the, 39, 40 - - Natural Selection, Early Impressions on Darwin, 30, 45, 46; - Survival of the Fittest, 56; - Specific Centres, 57; - Darwin’s Paper on, 65; - Theory of, 68–70; - Wallace’s Discovery of, 88–91; - Lord Salisbury’s Attack on, 82, 138; - Canon Tristram, the First Publicly to Accept the Theory, 92–94; - Argument for, 100–103; - Huxley not convinced as to Sufficiency of the Evidence of, 121, - 123, 124, 126; - as the Highest Attempt to Account for Evolution, 129; - Huxley’s Description of the Theory, 136, 137; - H. C. Watson on, 144; - Hostile Criticisms, 144, _et seq._; - Why the Term was Chosen, 147 - - “Naturalist’s Voyage, A,” Completion of, 30 - - Newton, Prof., Speech at the British Association, 153 - - _Nineteenth Century_, The Duke of Argyll’s Article in the, 144 - - - Orchids, the Fertilisation of, 193 - - Origin of Species, Darwin’s Theory of the; - Early Reflections upon, 25–29; - Growth of the Theory, 42; - Separate Creation Theory Inadequate, 42; - Principles of Development, 45; - First Account of Darwin’s Theory, 46; - the Sketch Enlarged, 46; - Profs. Huxley and Newton’s Criticisms, 46, 47; - Divergence of Character, 47, 48; - Competition, 47, 56; - Darwin’s Arrangements for the Publication in case of his Death, 48; - Darwin and Wallace’s Joint Paper Presented to the Linnean Society, - 46, 62; - his Confidence, 48; - Correspondence with Friends, 50; - Immutability of Species denied, 50; - Theory not understood by Naturalists, 55; - the Polyphyletic Theory, 57; - Specific Centres, 57; - Darwin and Wallace, 60; - their Papers before the Linnean Society, 62–77; - Struggle for Life, 65–77; - Principles of, 68–70; - Comparison of the Joint Memoir, 78, _et seq._; - Preparation of the Work on, 95, _et seq._; - Interest of Lyell and Hooker in its Publication, 95; - Letters to John Murray, the Publisher, 97; - full Title of the Volume, 98; - Outline of the Book and its Various Editions, 100–104; - its Reception by Lyell, 105; - by Hooker, 111; - by Asa Gray, 112; - and by Huxley, 119; - Huxley’s Article in the _Times_, 124; - and in the _Westminster Review_, 125; - Huxley’s high Tribute to Darwin’s Theory, 130; - Difficulty with which Understood, 144, _et seq._; - Regarded by Darwin as an Abstract of a Larger Work, 162 - - Osborn, Prof., 79, 80 - - Oxford, the Bishop of, and Huxley, 155 - - - Pangenesis, Darwin’s Hypothesis of, 164, _et seq._; - his Confidence in the Theory, 180, _et seq._ - - Parallel Roads of Glen Roy, The, 31 - - Parthenogenesis, 164 - - Petrels at St. Kilda, West Indian nuts found in, 96 - - Plants and Animals, Variation of, under Domestication, 161; - Production of Abnormal Parts, 172; - Separate forms on same Individual, 175; - Different forms of Flowers on the same Species, 194; - Climbing, 196; - Power of Movements in, 197; - Insectivorous, 198 - - Pollen, Fertilisation of Ovule, 166 - - “Power of Movements in Plants, The,” 197 - - Protective Mimicry, 203 - - - Reproduction of an Amputated Limb or part, 170 - - Reproduction, Sexual and Asexual, 164, _et seq._ - - Reversion, 167, 175 - - Rolleston, Prof., 155, 156 - - Romanes, Prof. G. J., 185 - - - Salisbury, Lord, Speech at the British Association Meeting at Oxford, - 82, 83, 138 - - Scientific Discoverer, The Qualifications of a, 12 - - Seeds, Experiments on the Vitality of, in Salt-Water, 51, 52 - - Sedgwick, Prof., Darwin’s Friendship with, 18; - his Excursions with, 20 - - Sexual and Asexual Reproduction, 164, _et seq._; - Advantages of, 165; - Cross-Fertilisation in Plants, 166; - Characters, 174–177; - Selection Theory, 67, 188, _et seq._; - rejected by Wallace, 188; - Darwin’s Letter to Meldola, 201 - - Shrewsbury, Darwin’s Birthplace, 9; - and School-life at, 16; - Re-visited, 25 - - “South America,” 190 - - South America, Some Observations on the Geology of, 26 - - Species, New, The Origin of, 56, _et seq._; - “Species not Transmutable,” Dr. Bree’s Book, 149 - - Species-mongers, Darwin’s Dislike of, 39, 40 - - Speculation and Hypothesis, 14, 15 - - Spencer, Herbert, Term of Survival of the Fittest, 148 - - Spontaneous Generation, 108, 159 - - Sterility of Hybrids, 171 - - Struggle for Existence, The, 65–67, 71–77 - - Survival of the Fittest, The, 148 - - - Teleology, 113, 114 - - Ternate, Wallace’s house at, 63 - - _Times_, Huxley’s Article on the Origin of Species in, 124 - - Transmutation of Species, 26, 149 - - Tristram, Canon, 92–94; - Paper on Ornithology of Northern Africa, 92 - - Tuckwell, Rev. W., 155 - - Turkeys, Experimenting upon with Distasteful Caterpillars, 216 - - Tyndall, Prof., 157 - - - Use and Disuse, The Inherited Effects of, 167, 179 - - - Variability, 167, 173 - - Variation, of Organic Being, Darwin’s Papers upon, 65; - Wallace’s Paper on, 71, _et seq._; - and Selection Relative Importance of, 96; - Under Domestication, 115, 161 - - Varieties, Departure from the Original Type, 71–77 - - “Volcanic Islands,” 190 - - - Wallace, Alfred Russel, and Darwin’s Joint Paper Presented to Linnean - Society, 46, 62; - and Darwin, 53, 60–64, 81–86, 134; - Paper Published on the Law Regulating new Species, 60; - Essays on Variations from Original Type, 61, 71–77; - house at Ternate, 63; - Comparison of the Joint Memoir, 78–86; - his Discovery of Natural Selection, 87–91; - Darwin’s Letter on Bastian’s Theory of Archebiosis, 160; - Darwin’s Letter to, on Pangenesis, 182 - - Watson, H. C., 144 - - Wedgwood, Josiah, 18 - - Weismann, Prof., on Germ-Plasm, 179; - “Studies in the Theory of Descent,” Meldola’s Translation, 205–210 - - _Westminster Review_, Huxley’s Article on Origin of Species in, 125 - - Wilberforce, Bishop, 149 - - - Zoology of the Voyage of the “Beagle,” The, 31 - - -PRINTED BY CASSELL & COMPANY, LIMITED, LA BELLE SAUVAGE, LONDON, E.C. - - - - - * * * * * * - - - - -Transcriber’s note: - -Punctuation, hyphenation, and spelling were made consistent when a -predominant preference was found in the original book; otherwise they -were not changed. - -Simple typographical errors were corrected; unpaired quotation -marks were remedied when the change was obvious, and otherwise left -unpaired. - -Running page headers in the original book are shown here as sidenotes. - -Dates and locations in the headings of letters usually were on the same -line in the original book, but have been placed on separate lines here. - -Footnotes, originally at the bottoms of pages, have been collected, -resequenced, and placed just above the Index. - -The Index was not checked for proper alphabetization or correct page -references. - -Cover created by Transcriber and placed into the Public Domain. - -Page 197: The correct title of “The Power of Movements in Plants” is -“The Power of Movement in Plants.” - - - -***END OF THE PROJECT GUTENBERG EBOOK CHARLES DARWIN AND THE THEORY OF -NATURAL SELECTION*** - - -******* This file should be named 65779-0.txt or 65779-0.zip ******* - - -This and all associated files of various formats will be found in: -http://www.gutenberg.org/dirs/6/5/7/7/65779 - - -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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