These quotations make plain the historical fact that Huxley was convinced of evolution because Darwin, by his theory of natural selection, brought forward an actual cause that could be seen in operation, and that was competent to produce new species. As soon as the "flash of light" came, it revealed to Huxley the vast store of evidence that he had unconsciously accumulated, and it set him at once to work collecting more evidence. If we bear in mind the distinction between evolution and natural selection, the well-known subsequent history of the relations between Huxley and what was known popularly as Darwinism becomes clear and intelligible. From first to last he accepted evolution; from first to last he accepted natural selection as by far the most reasonable hypothesis that had been brought forward, and as infinitely more in accordance with the observed facts of nature than any theory of the immediate action of supernatural creative power. As time went on, and the influence of Darwin's theory made evolution acceptable to a wider and wider range of people, until it passed into the common knowledge of the world, that confusion of which we have spoken arose between evolution and Darwin's particular theory. And as knowledge grew, and the number of biologists increased in the striking fashion of this last half-century, while the evidence for evolution continued to increase with an unexpected rapidity, every detail of the purely Darwinian theory became more and more subjected to rigid scrutiny. Most educated people, unless their education has been largely in an experimental science, find difficulty in understanding the relation in the minds of naturalists between "authority" and "knowledge." We do not know, for instance, that the structure of the Medusae consists essentially of two foundation-membranes, because Huxley, one of the greatest authorities in anatomy that the world has seen, told us that it was so. We know it because, Huxley having told us that it was so, we are able at any time with a microscope and dissecting needles to observe the fact for ourselves. It is true, that unless we are making a special study of the Medusae we do not repeat the observation in the case of so many different forms of Medusae as Huxley studied; but it is part of our training to observe for ourselves in a sufficient number of cases to test the correspondence between statement and fact before we accept the generalisation of any authority. And we learn, or at least have the opportunity of learning, in the whole habit of our lives as naturalists, to distinguish carefully between knowledge of which personal observation is an essential part, and opinion or belief which may or may not be based upon authority, but which in any case is devoid of the corroboration of personal observation. When a piece of new anatomical or physiological work is published in a technical journal, it is read by a large number of anatomists and physiologists, and if the work is apparently of an important kind, bearing on the general problems that even specialists have to follow, they all at once set to work in their laboratories to make corroborative dissections or experiments, and it is part of every modern account of a biological discovery to tell exactly the methods by which results were got, in order that this process of corroboration may be set about easily. The question as to whether or no natural selection were the sole or chief cause, or indeed a cause at all, of evolution is not yet, and perhaps never will be, a matter of knowledge in the scientific sense. At the most, we can see for ourselves only that selection does bring about changes at least as great as the differences between natural species. The evidence for this we have before our eyes, if we choose to see, on a stock farm; in the breeding yards of any keeper of "fancy" animals; or in the nursery gardens of any florist. So far, Huxley accepted the Darwinian principle as a definite contribution to knowledge; and so far the whole body of biologists has followed him. Beyond this the truth of the Darwinian principle is a matter of inference or judgment; of balancing probabilities and improbabilities. In multitude of counsellors there is said to be wisdom, and what we learn from the counsellors of biology all over the world is that some maintain that natural selection is the only probable agency in effecting evolution, and that it is competent to account for all the changes which we know to have taken place; others hold that its probable influence has been over-rated; and others, again, think that it has been one of the many causes that have brought about the kaleidoscopic variety of organic nature. Huxley remained to the last among those who distinguished in the clearest way between natural selection as an exceedingly ingenious and probable hypothesis, and a proved cause; and he was always careful, especially when he was writing for or speaking in the presence of those who like himself accepted the fact of evolution as proven, to distinguish between this provisional hypothesis as to how evolution had come about, and definite knowledge that it had come about in this way. Two passages from Huxley's writings, one written in 1860 in the Westminster Review, and the second written in 1893, in the preface to the volume of his collected essays which contained a reprint of the Westminster article, will make plain the continuity of Huxley's attitude:

"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 phenomena 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 rank 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 assuredly with 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 natural or artificial. 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 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 the 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 or overlooked."—(Westminster Review, 1860.)

"We should leave a very wrong impression on the reader's mind if we permitted him to suppose that the value of Darwin's 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 statement of well-sifted facts bearing on the doctrine of species that has ever appeared. The chapters on variation, on the struggle for existence, on instinct, on hybridism, on the imperfection of the geological record, on geographical distribution, have not only no equals, but, so far as our knowledge goes, no competitors, within the range of biological literature. And viewed as a whole, we do not believe that, since the publication of Von Baer's Researches on Development, thirty years ago, any work has appeared calculated to exert so large an influence, not only on the future of biology, but in extending the domination of science over regions of thought into which she has, as yet, hardly penetrated."—(Ibid.)

"Those who take the trouble to read the essays published in 1859 and 1860, will, I think, do me the justice to admit that 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, the fact of evolution is to my mind sufficiently evidenced by palaeontology; 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 quite incomplete. We still remain very much in the dark about the causes of variation; the apparent inheritance of acquired characters in some cases; and the struggle for existence within the organism, which probably lies at the bottom of both these phenomena."—(1893, Preface.)

Finally, when he was awarded the Darwin Medal of the Royal Society, on November 30, 1894, in the course of an address at the anniversary dinner of the Society, he said, as reported in the Times next day:

"I am as much convinced now as I was thirty-four 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 thirty-four 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 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 before us the Darwinian doctrines may be such as to be destined to survive or not, is more, I venture to think, than anybody is capable at this present moment of saying."

Further details of Huxley's relation to natural selection may be gained from an interesting chapter in Professor Poulton's volume on Charles Darwin (Cassell and Co., London, 1896).

FOOTNOTES:

[Footnote D: See E. Clodd's Pioneers of Evolution, London, 1897, and Osborn's From the Greeks to Darwin, New York, 1896.]



CHAPTER VII

THE BATTLE FOR EVOLUTION

Huxley's Prevision of the Battle—The Causes of the Battle—The Times Review—Sir Richard Owen attacks Darwinism in the Edinburgh Review—Bishop Wilberforce attacks in the Quarterly Review—Huxley's Scathing Replies—The British Association Debates at Oxford—Huxley and Wilberforce—Resume of Huxley's Exact Position with Regard to Evolution and to Natural Selection.

When Huxley wrote thanking Darwin for the first copy of the Origin, he warned him of the annoyance and abuse he might expect from those whose opinions were too suddenly disturbed by the new exposition of evolution, and assured him of the strongest personal support:

"I trust you will not allow yourself to be in any way disgusted or annoyed by the considerable abuse and misrepresentation which, unless I greatly mistake, is in store for you. Depend upon it, you have earned the lasting gratitude of all thoughtful men; and as to the curs which will bark and yelp, you must recollect that some of your friends, at any rate, are endowed with an amount of combativeness which (though you have often and justly rebuked it) may stand you in good stead.

"I am sharpening my claws and beak in readiness."

Huxley was absolutely right in his prediction as to the magnitude of the prejudices to be overcome before evolution became accepted, and for the next thirty years of his life he was the leader in the battle for Darwinism. It was natural that the new views, especially in their extension to man himself, should arouse the keenest opposition. To those of the present generation, who have grown up in an atmosphere impregnated by the doctrine of descent, the position of the world in 1860 seems "older than a tale written in any book." As we have tried to shew in the preceding chapter, biological science was partially prepared; the mutability of species and the orderly succession of organic life were in the air. But the application of the doctrine to man came as a greater shock to civilised sentiment than would have occurred a century earlier. It came as a disaster even to the clearest and calmest intellects, for it seemed to drag down to the dirt the nobility of man. Out of the fierce flame of the French Revolution, there had come purged and clean the conception of man as an individual and soul. As this century advanced, the conception of the dignity and worth of each individual man, rich or poor, bond or free, had spread more and more widely, bearing as its fruit the emancipation of slaves, the spread of political freedom, the amelioration of the conditions of the dregs of humanity, the right of all to education, the possibility of universal peace based on the brotherhood of man; and all that was best in philosophy and in political practice seemed bound up with a lofty view of the unit of mankind. Carlyle himself, to whom many of the freest and noblest spirits in Europe were beginning to look as to an inspired prophet, could see in it nothing but a "monkey damnification of mankind." The dogmatic world saw in it nothing but a deliberate and malicious assault upon religion. The Church of England in particular was beginning to recover from a long period of almost incredible supineness, and there was arising a large body of clergy full of faith and zeal and good works, but quite unacquainted with science, who frankly regarded Darwin as Antichrist, and Huxley and Tyndall as emissaries of the devil. Against evolutionists there was left unused no weapon that ignorant prejudice could find, whether that prejudice was inspired by a lofty zeal for what it conceived to be the highest interests of humanity, or by a crafty policy which saw in the new doctrine a blow to the coming renewed supremacy of the Church. To us, now, it may seem that Huxley had "sharpened his beak and claws" with the spirit of a gladiator rather than with that of the mere defender of a scientific doctrine; but a very short study of contemporary literature will convince anyone that for a time the defenders of evolution had to defend not only what they knew to be scientific truth, but their personal and private reputation. The new doctrine, like perhaps all the great doctrines that have come into the world, brought not peace but a sword, and had to be defended by the sword. Darwin had not the kind of disposition nor the particular faculties necessary for a deadly contest of this kind; he was interested indeed above all things in convincing a few leading naturalists of the truth of his opinions; but, that done, he would have been contented to continue his own work quietly, in absolute carelessness as to what the world in general thought of him. Huxley, on the other hand, was incapable of restraining himself from propagating what he knew to be the truth; his reforming missionary spirit was not content simply with self-defence; it drove him to be a bishop in partibus infidelium.

By a curious and interesting accident, Huxley had the opportunity of beginning his propagandism by writing the first great review of The Origin of Species in the Times, at that period without question the leading journal in the world. Huxley's own account of this happy chance is given in Darwin's Life and Letters, vol. ii.

"The Origin was sent to Mr. Lucas, one of the staff of the Times writers at that day, in what I suppose was the ordinary course of business. Mr. Lucas, though an excellent journalist, and at a later period editor of Once a Week, was as innocent of any knowledge of science as a babe, and bewailed himself to an acquaintance on having to deal with such a book, whereupon he was recommended to ask me to get him out of his difficulty, and he applied to me accordingly, explaining, however, that it would be necessary for him formally to adopt anything I might be disposed to write, by prefacing it with two or three paragraphs of his own.

"I was too anxious to seize on the opportunity thus offered of giving the book a fair chance with the multitudinous readers of the Times to make any difficulty about conditions; and being then very full of the subject, I wrote the article faster, I think, than I ever wrote anything in my life, and sent it to Mr. Lucas, who duly prefixed his opening sentences. When the article appeared, there was much speculation as to its authorship. The secret leaked out in time, as all secrets will, but not by my aid; and then I used to derive a good deal of innocent amusement from the vehement assertions of some of my more acute friends, that they knew it was mine from the first paragraph." "As the Times some years since referred to my connection with the review, I suppose there will be no breach of confidence in the publication of this little history."

This review was one of the few favourable notices, and naturally it delighted Darwin greatly. He wrote to Hooker about it: "Have you seen the splendid essay and notice of my book in the Times? I cannot avoid a strong suspicion that it is by Huxley; but I have never heard that he wrote in the Times. It will do grand service." On the same day, writing to Huxley himself, he said of the review:

"It included an eulogium of me which quite touched me, although I am not vain enough to think it all deserved. The author is a literary man and a German scholar. He has read my book attentively; but, what is very remarkable, it seems that he is a profound naturalist. He knows my barnacle book and appreciates it too highly. Lastly, he writes and thinks with quite uncommon force and clearness; and, what is even still rarer, his writing is seasoned with most pleasant wit. We all laughed heartily over some of the sentences.... Who can it be? Certainly I should have said that there was only one man in England who could have written this essay, and that you were the man; but I suppose that I am wrong, and that there is some hidden genius of great calibre; for how could you influence Jupiter Olympus and make him give you three and a half columns to pure science? The old fogies will think the world will come to an end. Well, whoever the man is, he has done great service to the cause."

The essay in the Times was followed shortly afterwards by a "Friday Evening Discourse" in 1860 on "Species, Races, and their Origin," in which Huxley, addressing a cultivated audience, laid the whole weight of his brilliant scientific reputation on the side of evolution. Next, in April, 1860, he published a long article in the Westminster Review, then a leading organ of advanced opinion, on The Origin of Species, some quotations from which article were made in the last chapter. Apart from its strong support of the doctrine of evolution, its whole-hearted praise of Darwin's achievements, and the clear way in which, while it showed the value of natural selection as the only satisfactory hypothesis in the field, it gave reasons for regarding it strictly as an hypothesis, the review is specially interesting as a contrast to reviews which appeared about the same time in the Edinburgh Review and in the Quarterly. Both these were not only exceedingly unfavourable, but were written in a spirit of personal abuse singularly unworthy of their authors and still more of their subject. The review in the Edinburgh had come as a particularly great shock to Darwin, Huxley, and their friends. Sir Richard Owen, in many ways, was at that time the most distinguished anatomist in England. He had been an ardent follower of Cuvier, and in England had carried on the palaeontological work of the great Frenchman. He was a personal friend of the court, a well-known man in the best society, and in many ways a worthy upholder of the best traditions of science. In the particular matter of species, he was known to be by no means a firm supporter of the orthodox views. When Darwin's paper was read at the Linnaean Society, and afterwards when the Origin was published, the verdict of Owen was looked to with the greatest interest by the general public. For a time he wavered, and even expressed himself of the opinion that he had already in his published works included a considerable portion of Darwin's views. But two things seemed to have influenced him: First, Wilberforce, the Bishop of Oxford, and Sedgwick and Whewell, the two best-known men at Cambridge, urged him to stamp once for all, as he only could do, upon this "new and pernicious doctrine." Secondly, combined with his great abilities, he had the keenest personal interest in his own position as the leader of English science, and had no particular friendship for men or for views that seemed likely to threaten his own supreme position. In a very short time he changed from being neutral, with a tendency in favour of the new views, to being a bitter opponent of them. In scientific societies and in London generally, naturally enough he constantly came across the younger scientific men, such as Huxley and Hooker, who had declared for Darwin, and he made the irretrievable mistake of for a time attempting to disguise his opposition while he was writing the most bitter of all the articles against Darwinism. That appeared in the Edinburgh Review in April, 1860, and the range of knowledge it displayed, and the form of arguments employed, naturally enough betrayed the secret of its authorship, although Owen for very long attempted to conceal his connection with it. Darwin, who had the most unusual generosity towards his opponents, found this review too much for him. Writing to Lyell soon after its publication, he said:

"I have just read the Edinburgh, which, without doubt is by ——. It is extremely malignant, clever, and, I fear, will be very damaging. He is atrociously severe on Huxley's lecture, and very bitter against Hooker. So we three enjoyed it together. Not that I really enjoyed it, for it made me uncomfortable for one night; but I have quite got over it to-day. It requires much study to appreciate all the bitter spite of many of the remarks against me; indeed I did not discover all myself. It scandalously misrepresents many parts. He misquotes some passages, altering words within inverted commas.... It is painful to be hated in the intense degree with which —— hates me."

As Owen was still alive when this letter was published in Darwin's Life, the authorship of the review was not actually mentioned; but it is necessary to mention it, as it justifies the sternness with which Huxley exposed Owen on an occasion shortly to be described. The review in the Quarterly was written by Wilberforce, the Bishop of Oxford, in July, 1860, and almost at once the authorship of it became known to Darwin's friends. In connection with this, Huxley wrote in 1887, in Darwin's Life and Letters:

"I doubt if there was any man then living who had a better right (than Darwin) to expect that anything he might choose to say on such a question as the Origin of Species would be listened to with profound attention, and discussed with respect. And there was certainly no man whose personal character should have afforded a better safeguard against attacks, instinct with malignity and spiced with shameless impertinences. Yet such was the portion of one of the kindest and truest men that it was ever my good fortune to know; and years had to pass away before misrepresentation, ridicule, and denunciation ceased to be the most notable constituents of the majority of the multitudinous criticisms of his work which poured from the press. I am loth to rake up any of these ancient scandals from their well-deserved oblivion; but I must make good a statement which may seem overcharged to the present generation, and there is no piece justificative more apt for the purpose or more worthy of such dishonour than the article in the Quarterly Review for July, 1860. Since Lord Brougham assailed Dr. Young, the world has seen no such specimen of the insolence of a shallow pretender to a Master in Science as this remarkable production, in which one of the most exact of observers, most cautious of reasoners, and most candid of expositors, of this or any other age, is held up to scorn as a 'flighty' person who endeavours to 'prop up his utterly rotten fabric of guess and speculation,' and whose 'mode of dealing with nature' is reprobated as 'utterly dishonourable to natural science.' And all this high and mighty talk, which would have been indecent in one of Mr. Darwin's equals, proceeds from a writer whose want of intelligence, or of conscience, or of both, is so great, that, by way of an objection to Mr. Darwin's views, he can ask, 'Is it credible that all favourable varieties of turnips are tending to become men'; who is so ignorant of palaeontology that he can talk of the 'flowers and fruits' of the plants of the carboniferous epoch; of comparative anatomy, that he can gravely affirm the poison apparatus of venomous snakes to be 'entirely separate from the ordinary laws of animal life, and peculiar to themselves'; of the rudiments of physiology, that he can ask, 'what advantage of life could alter the shape of the corpuscles into which the blood can be evaporated?' Nor does the reviewer fail to flavour this outpouring of incapacity with a little stimulation of the odium theologicum. Some inkling of the history of the conflicts between astronomy, geology, and theology leads him to keep a retreat open by the proviso that he cannot 'consent to test the truth of Natural Science by the Word of Revelation,' but for all that he devotes pages to the exposition of his conviction that Mr. Darwin's theory 'contradicts the revealed relation of the creation to its Creator,' and is 'inconsistent with the fulness of His glory.'"

In a footnote to this passage, Huxley wrote that he was not aware when writing these lines that the authorship of the article had been avowed publicly. He adds, however:

"Confession unaccompanied by penitence, however, affords no ground for mitigation of judgment; and the kindliness with which Mr. Darwin speaks of his assailant, Bishop Wilberforce, is so striking an exemplification of his singular gentleness and modesty, that it rather increases one's indignation against the presumption of his critic."

As a matter of fact Wilberforce was a man of no particular information in letters or in philosophy, and his knowledge of science was of the vaguest: a little natural history picked up from Gosse, the naturalist of the seashore, in the course of a few days' casual acquaintance at the seaside, and some pieces of anatomical facts with which he was provided, it is supposed, by Owen, for the purposes of the review. But he bore a great name, and misused a great position; he was a man of facile intelligence, smooth, crafty, and popular, and in this case he was convinced that he was doing the best possible for the great interests of religion by authoritatively denouncing a man whose character he was incapable of realising, and on whose work he was incompetent to pronounce an opinion. Against an enemy of this kind, Huxley was implacable and relentless. He was constitutionally incapable of tolerating pretentious ignorance, and he had realised from the first that there could be no question of giving and taking quarter from persons who were more concerned to suppress doctrines they conceived to be dangerous than to examine into their truth. On the other hand, much as Huxley disliked Owen's devious ways, and although in after life there occurred many and severe differences of opinion between Huxley and Owen, Huxley had a sincere respect for much of Owen's anatomical and palaeontological work, and when, in 1894, Owen's Life was published, one of the most interesting parts of it was a long, fair, and appreciative review by Huxley of Owen's contributions to knowledge.

The middle of 1860, however, was not a time for Huxley, in his capacity as Darwin's chief defender, to make truce with the enemy. In England a certain number of well-known scientific men had given a general support to Darwinism. From France, Germany, and America there had come some support and a good deal of cold criticism, but most people were simmering with disturbed emotions. The newspapers and the reviews were full of the new subject; political speeches and sermons were filled with allusions to it. Wherever educated people talked the conversation came round to the question of evolution. Were animals and plants the results of special creations, or were they, including man, the result of the gradual transformations of a few simple primitive types evolving under the stress of some such force as Darwin's natural selection? To many people it seemed to be a choice between a world with God and a world without God; and the accredited defenders of religion gathered every force of argument, of misrepresentation, conscious and unconscious, of respectability, and of prejudice to crush once for all the obnoxious doctrine and its obnoxious supporters. In the autumn of that year it fell that the meeting of the British Association, then coming into prominence as the annual parliament of the sciences, was to be held at Oxford. It was inevitable that evolution should be debated formally and informally in the sessions of the Association, and it must have seemed to the orthodox that there, in that beautiful city, its air vibrant with tinkling calls to faith, its halls and libraries crowded with the devout and the learned, its history and traditions alike calling on all to defend the old fair piety, in such an uncongenial air, the supporters of evolution must be overwhelmed. Almost the whole weight of the attack had to be resisted by Huxley. In the various sectional meetings he had combat after combat with professors and clerics. Of these dialectic fights the most notable were one with Owen on the anatomical structure of the brain, and another with Wilberforce upon the general question of evolution. Owen contended that there were anatomical differences not merely of degree but of kind between the brain of man and the brain of the highest ape, and his remarks were accepted by the audience as a complete and authoritative blow to the theory of descent. Huxley at once met Owen with a direct and flat contradiction, and pledged his reputation to justify his contradiction with all due detail on a further occasion. As a matter of fact, he did justify the contradiction, and no anatomist would now dream of attempting the support of the proposition rashly made by Owen; but, at the time, the position of Owen and the sympathies of the audience took away much of their effect from Huxley's words. Two days later, Wilberforce, in a scene of considerable excitement, made a long, eloquent, and declamatory speech against evolution and against Huxley. From the incomplete reports of the debate that were published, it is difficult to gain a very clear idea of the Bishop's speech; but it is certain that it was eloquent and facile, and that it appealed strongly to the religious prejudices of the majority of the audience. He ended by a gibe which, under ordinary circumstances, might have passed simply as the rude humour of a popular orator, but which in that electric atmosphere stung Huxley into a retort that has become historical. He asked Huxley whether he was related by his grandfather's or grandmother's side to an ape. Huxley replied:

I asserted, and I repeat, that a man has no reason to be ashamed of having an ape for his grandfather. If there were an ancestor whom I should feel shame in recalling, it would be a man, a man of restless and versatile intellect, who, not content with an equivocal success in his own sphere of activity, plunges into scientific questions with which he has no real acquaintance, only to obscure them by an aimless rhetoric, and distract the attention of his hearers from the real point at issue by eloquent digressions, and skilled appeals to religious prejudice.

An eye-witness has told the present writer that Huxley's speech produced little effect at the time. In the minds of those of the audience best qualified to weigh biological arguments, there was little doubt but that he had refuted Owen, and simply dispelled the vaporous effusions of the Bishop; but the majority of the audience retained the old convictions. The combat was removed to a wider tribunal. From that time forwards Huxley, by a series of essays, addresses, and investigations, continued almost to the end of his life, tried to convince, and succeeded in convincing, the intellectual world. At the risk of wearying by repetition we shall again insist upon the side of Darwinism that Huxley fought for and triumphed for.

Long before the time of Darwin and Huxley, almost at the beginning of recorded thought, philosophers busied themselves with the wonderful diversity of the living world and with speculations as to how it had assumed its present form. From the earliest times to this century, theories as to the living world fell into one or other of two main groups. The key-note of one group was the fixity of species: the belief that from their first appearance species were separate, independent entities, one never springing from another, new species never arising by the modification in different directions of descendants of already existing species. The key-note of the other group of theories was the idea of progressive change: that animals and plants as they passed along the stream of time were continually being moulded by the forces surrounding them, and that the farther back the mind could go in imagination the fewer and simpler species would be; until, in the first beginning, all the existing diverse kinds of living creatures would converge to a single point. It may be that, on the whole, the idea of fixity prevailed more among thinkers with a religious bias; but for the most part the theories were debated independently of the tenets of any faith, Christian or other. There were sceptical defenders of fixity and religious upholders of evolution. However, in Christian countries, from the time of the Reformation onwards, a change in this neutrality of religion to theories of the living world took place. As Pascal prophesied, Protestantism rejected the idea of an infallible Church in favour of the idea of an infallible book, and, because it happened that this book included an early legend of the origin of the world in a form apparently incompatible with evolution, Protestantism and, to a lesser and secondary extent, Catholicism, assumed the position that there was no place for evolution in a Christian philosophy. At the end of last century, and up to the middle of this century, the problem was not raised in any acute form. The chief anatomists and botanists were occupied with the investigation and discovery of facts, and, in an ordinary way, without taking any particular trouble about it, accepted more or less loosely the idea that species were fixed. Now and then an evolutionist propounded his views; but, as a rule, he supported them with a knowledge of facts very much inferior to that possessed by the more orthodox school. Then came Herbert Spencer, reasserting evolution in the old broad spirit, not merely in its application to species, but as the guiding principle of the whole universe from the integrations of nebulae into systems of suns and planets to the transformations of chemical bodies. Before his marvellous generalisations had time to grip biologists, there came Darwin; and Darwin brought two things: first, a re-statement of the fact of evolution as applied to the living world, supported by an enormous body of evidence, new and old, presented with incomparably greater force, clearness, patience, and knowledge than had ever been seen before; and, second, the exposition of the principle of natural selection as a mechanism which might have caused, and probably did cause, evolution.

Huxley, as has been shewn, like many other anatomists, was ready for the general principle of evolution. In fact, so far as it concerned the great independent types which he believed to exist among animals, he was more than prepared for it. Let us take a single definite example of his position. In his work on the Medusae, he had shewn how a large number of creatures, at first sight diverse, were really modifications of a single great type, and he used language which, now that all zooelogists accept evolution in the fullest way, requires no change to be understood:

"What has now been advanced will, perhaps, be deemed evidence sufficient to demonstrate,—first, that the organs of these various families are traceable back to the same point in the way of development; or, secondly, when this cannot be done, that they are connected by natural gradations with organs which are so traceable; in which case, according to the principles advanced in 57, the various organs are homologous, and the families have a real affinity to one another and should form one group.... It appears, then, that these five families are by no means so distinct as has hitherto been supposed, but that they are members of one great group, organised upon one simple and uniform plan, and, even in their most complex and aberrant forms, reducible to the same type. And I may add, finally, that on this theory it is by no means difficult to account for the remarkable forms presented by the Medusae in their young state. The Medusae are the most perfect, the most individualised animals of the series, and it is only in accordance with what very generally obtains in the animal kingdom, if, in their early condition, they approximate towards the simplest forms of the group to which they belong."

Such words, written before 1849, only differ from those that would have been written by a convinced evolutionist by a hair's breadth. But Huxley was not an evolutionist then: it was Darwin's work, containing a new exposition of evolution and the new principle of natural selection, that convinced him, not of natural selection but of evolution. At Oxford, in 1860, it was for evolution, and not for natural selection, that he spoke; and throughout his life afterwards, as he expressed it, it was this "ancient doctrine of evolution, rehabilitated and placed upon a sound scientific foundation, since, and in consequence of, the publication of The Origin of Species," that furnished him with the chief inspiration of his work. The clear accuracy of his original judgment upon Darwin's work has been abundantly justified by subsequent history. Since 1859 the case for evolution has become stronger and stronger until it can no longer be regarded as one of two possible hypotheses in the field, but as the only view credible to those who have even a moderate acquaintance with the facts. In 1894, thirty years after the famous meeting at Oxford, the British Association again met in that historic town. The President, Lord Salisbury, a devout Churchman and with a notably critical intellect, declared 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."

Huxley, in replying to the address, used the following words:

"As he noted in the Presidential Address to which they had just listened with such well deserved interest, he found it stated, on what 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."

On the other hand, Huxley all through his life, while holding that natural selection was by far the most probable hypothesis as to the mode in which evolution had come about, maintained that it was only a hypothesis, and, unlike evolution, not a proved fact. In 1863, in a course of lectures to workingmen, he declared:

"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.... 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."

In 1878 he wrote:

"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 difficulty in accepting natural selection as more than a hypothesis is simply that we have no experimental knowledge of its being able to produce the mutual infertility which is so striking a character of species. This difficulty is, in the first place, the difficulty of proving a negative. It might be possible to prove that its operation actually does produce species; it will always be impossible to prove that, in the past, natural selection, and no other known or unknown agency or combination of agencies, had a share in the process. All naturalists are now agreed that, as a matter of historical fact, it was the propounding of natural selection by Darwin that led to the acceptance of evolution, to the fact that evolution "takes its place alongside of those accepted truths which must be reckoned with by philosophers of all schools." The difficulty as to natural selection still exists, and there is no better way to express it than in Huxley's words, written in the early sixties:

"But, for all this, our acceptance of the Darwinian hypothesis must be provisional so long as one link in the chain of evidence is wanting; and, so long as all the animals and plants certainly produced by selective breeding from a common stock are fertile with one another, that link will be wanting; for, so long, selective breeding will not be proved to be competent to do all that is required of it to produce natural species.... I adopt Mr. Darwin's hypothesis, therefore, subject to the production of proof that physiological species may be produced by selective breeding; just as a physical philosopher may accept the undulatory theory of light, subject to the proof of the existence of the hypothetical ether; or as the chemist adopts the atomic theory, subject to the proof of the existence of atoms; and for exactly the same reasons, namely, that it has an immense amount of prima facie probability; that it is the only means at present within reach of reducing the chaos of observed facts to order; and, lastly, that it is the most powerful instrument of investigation which has been presented to the naturalists since the invention of the natural system of classification, and the commencement of the systematic study of embryology."—Man's Place in Nature, p. 149.[E]

FOOTNOTES:

[Footnote E: Further details on the subject of this chapter may be obtained in Clodd's excellent volume, Pioneers of Evolution, where an account of the history of the idea of evolution from the earliest times is given; and in Poulton's Charles Darwin and the Theory of Natural Selection, where there is a particularly valuable chapter upon Huxley's relation to Darwinism.]



CHAPTER VIII

VERTEBRATE ANATOMY

The Theory of the Vertebrate Skull—Goethe, Oken, Cuvier, and Owen—Huxley Defends Goethe—His Own Contributions to the Theory—The Classification of Birds—Huxley Treats them as "Extinct Animals"—Geographical Distribution—Sclater's Regions—Huxley's Suggestions.

We have seen that some of the most important of the contributions made by Huxley to zooelogical knowledge were in the field of the lower animals, especially of those marine forms for the study of which he had so great opportunities on the Rattlesnake. A great bulk of his zooelogical work, however, related to the group of back-boned animals. These, by their natural affinities and anatomical structure, are more closely related to man, and, as Huxley began his scientific work as a medical student, the groundwork of all his knowledge was study of the anatomy and physiology of man. Moreover, throughout the greater part of his working life, he had more to do with the extinct forms of life. The vertebrate animals, from the great facility for preservation which their hard skeleton presents, as well as from the extremely important anatomical characters of the skeleton, bulk more largely in the study of palaeontology than does any other group. In each of the great groups of vertebrate animals, in fishes, amphibia, reptiles, birds, and mammals, Huxley did important work. Much of this is embodied in his treatise on Vertebrate Anatomy, but to some particular parts of it special attention may now be directed, as much because these serve as excellent examples of his method of work as because of their intrinsic importance.

The skull is the most striking feature in the skeleton of vertebrate animals, and to the theory and structure of the vertebrate skull Huxley paid special attention, and his views and summary of the views of others form the basis of our modern knowledge. This work was put before the public in the course of a series of lectures on Comparative Anatomy given in 1863, while Huxley was Hunterian Professor at the Royal College of Surgeons, and the beginnings of it were contained in a Croonian lecture to the Royal Society in 1858.

The theory of the skull which held the field was known as the vertebral theory. The great bulk of the nervous system of vertebrate animals consists of a mass of tissue lying along the dorsal line of the body and enclosed in a cartilaginous or bony sheath. The nerve tissue is the brain and spinal cord; the sheath is the skull in front and the vertebral column along the greater part of the length of the animal. The brain may be taken simply as an anterior portion of the nerve mass, corresponding in a general way to an expansion of the spinal cord in the region of the anterior limbs and an expansion in the region of the hind limbs, the latter indeed having recently been shown in some extinct creatures to surpass the brain in size. In a similar simple fashion the skull may be taken as an expanded anterior part of the vertebral column, serving as an expanded box for the brain, just as in the regions of the pectoral and pelvic expansions of the cord there are similar expansions of the surrounding bony case. We know now, from greater knowledge of its embryological development, that the brain contains structures quite peculiar to itself, and differs from the spinal cord in kind as well as in size; but, at the same time, when the vertebral theory of the skull was inaugurated, embryological knowledge and the importance of its relation to anatomical structure were less considered. What Huxley did was to show that the skull, in its mode of origin and real nature, was not merely an expanded portion of the vertebral column, but that it differed from it in kind.

The hypothesis of the vertebral structure of the skull was due both to Goethe, the great German poet, and Oken, a most able but somewhat mystic German anatomist. An attempt had been made by a well-known English anatomist to cast on Goethe the stigma of having tried to rob Oken of the credit for this theory. Huxley set that matter finally at rest, disproving and repelling with indignation the unworthy suggestion. Oken gave out his theory in 1807, and described how it had been first suggested to his mind by the accident of picking up a dried and battered sheep's skull, in which the apparent vertebral structure was very obvious, as, indeed, anyone may see at a glance. It was in 1820, long after the theory had been made current, that the poet first publicly narrated that in a similar way he had long before come to the same conclusion; but Huxley was able to show that, although announcing it later, Goethe had in reality anticipated the anatomist. A passage occurs in a letter to a friend, of a date in 1790, which admits of no doubt. "By the oddest happy chance, my servant picked up a bit of an animal's skull in the Jews' cemetery at Venice, and, by way of a joke, held it out to me as if he were offering me a Jew's skull. I have made a great step in the formation of animals." It is an interesting trait in Huxley's character, to find him zealous in defence of the reputation of a great man, even although that man had been dead more than half a century; but it may be added that his just zeal was at least stimulated by the fact that the maligner of Goethe was Owen, the conduct of whom, with regard to Darwin and Huxley, Huxley had had just reason for resenting.

The theory, then, which had dropped stillborn from Goethe, but which Oken developed, was simply that the skull consisted of a series of expanded vertebrae. Each vertebra consists of a basal piece or centrum, the anterior and posterior faces of which are closely applied to the face of an adjoining vertebra, and of a bony arch or ring which encloses and protects the nervous cord. Oken supposed that there were four such vertebrae in the skull, the centra being firmly fused and the arches expanded to form the dome of the skull. Quite correctly, he divided the skull into four regions, corresponding to what he called an ear vertebra, at the back, through which the auditory nerves passed; a jaw vertebra, in the sphenoidal region, through which the nerves to the jaws passed; an eye vertebra in front, pierced by the optic nerves, and again in front a nose vertebra, the existence of which he doubted at first. Quite rightly, he discriminated between the ordinary bones of the skull and the special structures surrounding the inner ear which he declared to be additions derived from another source. So far it cannot be doubted that the vertebral theory made a distinct advance in our knowledge of the skull. It was to a certain extent, however, thrown into disrepute by various fantastic theories with which Oken surrounded it. Later on, Cuvier removed from it these wilder excrescences, and amplified the basis of observation upon which the underlying theory of the unity of type of the skull throughout the vertebrates was based. Cuvier, however, came to reject the theory, except so far as it applied to the posterior or occipital segment of the skull. Later on, Owen resuscitated the theory, first throwing doubt on the merit of Goethe, and then suggesting that Oken, instead of relying on the observed facts, had deduced the whole theory from his own imagination. Owen, although he made no new contribution to fact or theory in this matter, practically claimed the whole credit of it as a scientific hypothesis.

When Huxley took up the subject, the position was that the vertebral theory was in full possession of the field, under the auspices of Owen. Huxley began afresh from observed facts. The first object of his investigation was to settle once for all the question as to whether the skulls of all vertebrates were essentially modifications of the same type. He took in succession the skulls of man, sheep, bird, turtle, and carp, and showed that in all these there were to be distinguished the same four basi-cranial regions: the basi-occipital, basi-sphenoid, pre-sphenoid, and ethmoid. These were essentially identical with the centra of the four vertebrae of Oken. Similarly, he showed the composition of the lateral and dorsal walls, proving the essential identity of the structures involved and of their relations to the nerve exits in the great types he had chosen. In the series of lectures delivered before the College of Surgeons, he extended his observations to a much larger series of vertebrates, and substantially laid down the main lines of our knowledge of the skull. In two important respects his statements were not merely a codification of existing knowledge, but an important extension of it. He distinguished the different modes in which the jaws may be suspended to the skull, and established for these different kinds of suspensoria the names which have ever since been employed. He proved clearly what had been suggested by Oken, that the region of the ear is a lateral addition to the skull, and he distinguished in it three bones, his names for which have since become the common property of anatomists. Finally, he made it plain beyond any possible doubt that the skulls of all vertebrates were built upon a common plan.

Having established the facts, he proceeded to enquire into the theory. There was now a new method for investigating such problems, the method of embryology, which, practically, had not been available to Oken, and of which neither Cuvier nor Owen had made proper use. By putting together the investigations of a number of embryologists, by adding to these himself, and, lastly, by interpreting the facts which his investigations into comparative anatomy had brought to light, he shewed that the vertebral theory could not be maintained. He shewed, by these methods, that, though both skull and vertebral column are segmented, the one and the other, after an early stage, are fashioned on lines so different as to exclude the possibility of regarding the details of each as mere modifications of a common type. "The spinal column and the skull start from the same primitive condition, whence they immediately begin to diverge." "It may be true to say that there is a primitive identity of structure between the spinal or vertebral column and the skull; but it is no more true that the adult skull is a modified vertebral column than it would be to affirm that the vertebral column is a modified skull." Taking the embryological facts, he shewed that the skull arose out of elements quite different from those of the vertebral column. The notochord alone is common to both. The skull is built up of longitudinal cartilaginous pieces, now known as the "parachordals" and "trabeculae," of sense capsules enclosing the nose and ear, and of various roofing bones. In the historical development of the skull three grades become apparent; a primitive stage, as seen in Amphioxus, where there is nothing but a fibrous investment of the nervous structures; a cartilaginous grade, as seen in the skate or shark, where the skull is formed of cartilage, very imperfectly hardened by earthy deposits; a bony stage, seen in most of the higher animals. He shewed that in actual development of the higher animals these historical grades are repeated, the skull being at first a mere membranous or fibrous investment of the developing nervous masses, then becoming cartilaginous, and, lastly, bony. He made some important prophetic remarks as to the probable importance that future embryological work would give to the distinction between cartilage and membrane bones—a prophecy that has been more than fully realised by the investigations of Hertwig and of others. Our present knowledge of the skull differs from Huxley's conception practically only in a fuller knowledge of details. We know now that throughout the series there is a primitive set of structures common to all animals higher in the scale than Amphioxus, and forming the base and lateral walls of the skull. This is termed the Chondrocraninm, because it is laid down in cartilage; it is composed of the separate elements which Huxley indicated, and, in different animals, as Huxley suggested, the exact limits of the ossification of the primitive cartilages differ in extent, but occur in homologous situations. This primitive skull is roofed over by a series of membrane bones which have no connection in origin with the other portions of the skull, and which have no representative in the vertebral column, but which are the direct descendants of the bony scales clothing the external skin in cartilaginous fishes. In one respect only was Huxley erroneous. Partly by inadvertence, and partly because the minute details of vertebrate embryology became really familiar to zooelogists only after the elaborate work of Balfour of Cambridge, Huxley, in his account of the formation of the first beginnings of the skeleton in the embryo, made confusion between the walls of the primitive groove, which, in reality, give rise to the nervous structures, and those embryonic tissues which form the skeletal system.

The next great piece of work which we may take as typical of Huxley's contributions to vertebrate anatomy, is his classical study on the classification of birds. The great group of birds contains a larger number of species than is known in any other group of vertebrates, and, in this vast assemblage of forms there is strikingly little anatomical difference. The ostrich and the humming-bird might perhaps be taken as types of the extremest differences to be found, and yet, although these differ in size, plumage, adaptations, habits, mode of life, and almost everything that can separate living things, the two conform so closely to the common type of bird structure that knowledge of the anatomy of one would be a sufficient guide, down to minute details, for dissection of the other. None the less, there are hundreds of thousands of species of birds between these two types. It is not surprising that to reduce this vast assemblage of similar creatures to an ordered system of classification has proved one of the most difficult tasks attempted by zooelogists. Before Huxley, it had been attempted by a number of distinguished zooelogists; but, for the most part, these had relied too much on merely external characters and on superficial modifications in obvious relation to habits. When Huxley, in the course of a set of lectures on Comparative Anatomy, was about to approach the subject of birds he was asked by a zooelogist how he proposed to treat them. "I intend," he replied, "to treat them as extinct animals." By that he meant that it was his purpose to make a prolonged study of their skeletal structures the basis of his grouping, following the lines which Cuvier, Owen, and he himself had pursued so successfully in the case of the fossil remains of vertebrates. The result was that this first systematic study of even one set of the anatomical characters of the group completely reformed the method by which all subsequent workers have tried to grapple with the problem; ornithology was raised from a process akin to stamp-collecting to a reasoned scientific study. The immediate practical results were equally important. He was able to shew that among the innumerable known forms there were three grades of structure. The lowest had already been recognised and named by Haeckel; it consisted of the Saururae, or reptile-like, birds, and contained a single fossil form, Archaeopteryx, distinguished from all living birds by the presence of a hand-like wing in which the metacarpal bones were well developed and freely movable, and by the possession of a long lizard-like tail actually exceeding in length the remainder of the spinal column. The next group of Ratites, although it contained only the Ostrich, Rhea, Emu, Cassowary, and Apteryx, he shewed to be equivalent in anatomical coherence to the third great group of Carinates, which includes the vast majority of living birds. In his arrangement of the latter group, he laid most stress on the characters of the bony structures which form the palate, and by this simple means was able to lay down clearly at least the main lines of a natural classification of the group.

Huxley's work upon birds, like his work in many other branches of anatomy, has been so overlaid by the investigations of subsequent zooelogists that it is easy to overlook its importance. His employment of the skeleton as the basis of classification was succeeded by the work of others who made a similar use of the muscular anatomy, of the intestinal canal, of the windpipe, of the tendons of the feet, and many other structures which display anatomical modifications in different birds. The modern student finds that all these new sets of facts are much greater in bulk than the work of Huxley, and it is easy for him to remain in ignorance that they were all suggested and inspired by the method which Huxley employed. He finds that further research has supplanted some of Huxley's conclusions, and it is easy for him to remain in ignorance that the conclusions themselves suggested the investigations which have modified them. Huxley's anatomical work was essentially living and stimulating, and too often it has become lost to sight simply because of the vast superstructures of new facts to which it gave rise.

Closely associated with vertebrate anatomy is the subject of geographical distribution. In 1857 the study of this important department of zooelogy was placed on a scientific basis, practically for the first time, by a memoir on the geographical distribution of birds published in the Journal of the Linnaean Society of London. It was known in a general way that different kinds of creatures were found in different parts of the world, but little attempt had been made to map out the world into regions characterised by their animal and vegetable inhabitants, as the political divisions of the world are characterised by their different governments and policies. Mr. Sclater, who two years later became secretary of the Zooelogical Society of London, in his memoir introduced the subject in the following words:

"It is a well-known and universally acknowledged fact that we can choose two portions of the globe of which the respective fauna and flora shall be so different that we should not be far wrong in supposing them to have been the result of distinct creations. Assuming, then, that there are, or may be, more areas of creation than one, the question naturally arises how many of them are there, and what are their respective extents and boundaries; or, in other words, what are the most natural primary ontological divisions of the earth's surface?"

Mr. Sclater's answer was that there are six great regions; Neotropical, Nearctic, Palaearctic, Ethiopian, Indian, and Australian, and his answer, with minor alterations and the addition of a great wealth of detail, has been accepted by zooelogy.

Two years later, however, Darwin gave a new meaning and a new importance to Sclater's work, by the new interpretation he caused to be placed on the words "centres of creation." Sclater's facts and areas remained the same; Darwin rejected the idea of separate creations in the older sense of the words, and laid stress on the impossibility of accounting for the resemblances within a region and for the differences between regions by climatic differences and so forth. He raised the questions of modes of dispersal and of barriers to dispersal, of similarities due to common descent, and of the modifying results produced by isolation. He gave, in fact, a theory of the "creations" which Mr. Sclater had shewn to be a probable assumption. It was in the nature of things that Huxley should make a contribution to a set of problems so novel and of so much importance to zooelogy. In 1868, in the course of a memoir on the anatomy of the gallinaceous birds and their allies, he made a useful attempt, nearly the first of its kind, to correlate anatomical facts with geographical distribution. Having shewn the diverging lines of anatomical structure that existed in the group of creatures he had been considering, he went on to shew that there was a definite relation between the varieties of structure and the different positions on the surface of the globe occupied at the present time by the creatures in question. He made, in fact, the geographical position a necessary part of the whole idea of a species or of a group, and so introduced a conception which has become a permanent part of zooelogical science.

With regard to the number and limits of the zooelogical regions into which the world may be divided, Huxley raised a number of problems which have not yet reached a full solution. Mr. Sclater had divided the world into six great regions: the Nearctic, including the continent of North America, with an overlap into what is called South America by geographers; the Palaearctic, comprising Europe and the greater part of Asia; the Oriental, containing certain southern portions of Asia, such as India south of the Himalayas and many of the adjacent islands; the Ethiopian, including Africa, except north of the Sahara, and Madagascar; the Australian, containing Australia and New Zealand and some of the more southeastern of the islands of Malay; the Neotropical, including South America. Huxley first called attention to certain noteworthy resemblances between the Neotropical and the Australian regions of Sclater, and held that a primary division of the world was into Arctogaea, comprising the great land masses of the Northern Hemisphere with a part of their extension across the equator, and Notogaea, which contained Australia but not New Zealand and South America. Although this acute suggestion has not been generally accepted as a modification of Mr. Sclater's scheme, it called attention in a striking fashion to some very remarkable features in the distribution of animals. Subsequent writers have considerably extended Huxley's conception of the similarities to be found among the more southern land areas. They have pointed out that the most striking idea of the distribution of land and water on the surface of the globe is to be got by considering the globe alternately from one pole and from the other. In the south, a clump of ice-bound land, well within the Antarctic Circle, surrounds the pole. All else is a wide domain of ocean broken only where tapering and isolated tongues of land, South America, the Cape, Australia, lean down from the great land masses of the north. On the other hand, all the great land masses expand in the Northern Hemisphere, and shoulder one another round the North Pole. America is separated from Asia only by the shallowest and narrowest of straits; an elevation of a few fathoms would unite Greenland with Europe. Science points definitely to some part of the great northern land area as the centre of life for at least the larger terrestrial forms of life. We know that these arose successively, primitive birds like the ostriches being older than higher forms like the parrots and singing birds; the pouched marsupials preceding the antelopes and the lion; the lemurs coming before the man-like apes. Each wave of life spread over the whole area producing after its kind; then, pressing round the northern land area, it met a thousand different conditions of environment, different foods, enemies, and climates, and broke up into different genera and species. But there was never a wave of life that was not followed by another wave. In the struggle for existence between the newer and the older forms, the older forms were gradually driven southwards towards the diverging fringes of the land masses. The vanquished left behind them on the field of battle only their bones, to become fossils. Sometimes succeeding waves swept along to the extreme limits of the land, and many early types were utterly destroyed. But others found sanctuary in the ends of the South, and such survivors of older and earlier types of life cause a similarity between the southern lands that Huxley called Notogaea, although the extent of his region must be increased.

Recently, however, there has been a recurrence to Huxley's suggested union of South America and Australia, based on new evidence of a direct kind, quite different from that which had just been given. Various groups of naturalists have stated that there are similarities between the invertebrate inhabitants of Australia and of South America of a kind which makes the existence of a direct land connection in the Southern Hemisphere extremely probable. Moreover, Ameghino has recently described some marsupial fossils from South America which, he states, belong to the Australian group of Dasyuridae, and Oldfield Thomas has described a new mammal from South America which is unlike the opossums of America and like the diprotodonts of Australia. So that, while the general opinion has been against Huxley's division, Notogaea, in the strict meaning which he gave to it, there has recently been an opinion growing in its favour.

Huxley also made minor alterations in Mr. Sclater's scheme by forming an additional circumpolar region for the Northern Hemisphere, and by elevating New Zealand into a separate region, distinct from Australia. On these points there is a balance of opinion against his views.

Before leaving the subject of Huxley's contributions to vertebrate anatomy, the actual details of which would occupy far too much space, it is necessary to mention the great importance to zooelogy of the new terms and new ideas he introduced into classification. His mind was, above all things, orderly and comprehensive, and while, in innumerable minute points, from the structure of the palate of birds to the structure of the roots of human hair (actually the subject of Huxley's first published contribution to scientific knowledge), he added to the number of known facts, he did even more important work in co-ordinating and grouping together the known body of facts. To him are due not only the names, but the idea, that the mammalian animals fall into three grades of ascending complexity of organisation: the reptile-like Prototheria, which lay large eggs, and which have many other reptilian characters; the Metatheria, or marsupial animals; the Eutheria, or higher animals, which include all the common animals from the mole or rabbit up to man. In a similar fashion, he grouped the vertebrates into three divisions, and named them: Ichthyopsida, which include the fish and Amphibia, creatures in which the aquatic habit dominates the life history and the anatomical structure; Sauropsida, including birds and reptiles, on the close connection between which he threw so much light; Mammalia.



CHAPTER IX

MAN AND THE APES

Objections to Zooelogical Discussion of Man's Place—Owen's Prudence—Huxley's Determination to Speak out—Account of his Treatment of Man's Place in Nature—Additions Made by More Recent Work.

Even before the publication of The Origin of Species there was a considerable nervousness in the minds of the more orthodox as to discussions on the position of the human species in zooelogical classification. Men of the broadest minds, such as Lyell, who himself had suffered considerably from outside interference with the scientific right to publish scientific conclusions, was strongly opposed to anything that seemed to tend towards breaking down the barrier between man and the lower creatures. Sir William Lawrence, a very distinguished and able man, had been criticised with the greatest severity, and had been nearly ostracised, for a very mild little book On Man; and Huxley tells us that the electors to the Chair of a Scotch University had refused to invite a distinguished man, to whom the post would have been acceptable, because he had advocated the view that there were several species of man. The court political leaders, and society generally, resented strongly anything that seemed at all likely to disturb the somewhat narrow orthodoxy prevalent in those times; and, as there were comparatively few posts open to scientific men, and comparatively greater chances of posts being made for men of talent and ability who adhered to the respectable traditions, those who tampered with so serious a question as the place of man were likely to burn their fingers severely. However, the difficulties of discussing these problems were much greater immediately after 1859. One of the most surprising things in the history of this century is the sudden intensity of the opposition of the public, particularly the respectable and religious public, to zooelogical writing upon man, immediately after the publication of the Origin. Before that time anatomists did not necessarily hesitate to point out the close resemblance between the anatomy of man and that of the higher apes, and the difficulties anatomists had in making anatomical distinction of value between them. Thus Professor Owen, who, as a writer, was rather unusually nervous about expressing facts to which any objection might be raised by those outside the strictly scientific world, had written the following paragraph in the course of an essay on the characters of the class Mammalia, published, in 1857, in the Journal of the Proceedings of the Linnaean Society:

"Not being able to appreciate or conceive of the distinction between the psychical phenomena of a chimpanzee and of a Boschisman or of an Aztec, with arrested brain-growth, as being of a nature so essential as to preclude a comparison between them, or as being other than a difference of degree, I cannot shut my eyes to the significance of that all-pervading similitude of structure—every tooth, every bone, strictly homologous—which makes the determination of the difference between Homo and Pithecus the anatomist's difficulty."

It is true, he went on to explain his belief in the existence of certain characters in the brain which seemed to him to justify the separation of man in a different group from that in which the apes were placed; but it is certain that he regretted having said anything which seemed to support the Darwinian view; and, two years later, when the opposition to Darwin was in its acutest stage, Owen withdrew his words. His "Reade Lecture," delivered in the University of Cambridge, was in all respects a reprint of the essay from which we have just quoted, but the apparently dangerous words were omitted. More than that, the points insisted on in the essay as being sufficient for the purpose of separating man in zooelogical classification were elevated into a reason against descent. Although Huxley, in several addresses and publications, disproved the existence of the alleged differences, and although Sir William Flower gave an actual demonstration shewing the essential identity of the brain of man and of the apes in the matter in question, Owen never admitted his error.



It is not surprising that, if an anatomist so distinguished and acute as was Owen allowed his judgment to be completely overborne by the storm of prejudice against Darwinism, those who were not anatomists should have held up to ridicule all idea of comparison between man and the apes. In The Origin of Species itself, no elaborate attempt had been made to set forth the anatomical arguments in favour of or against a community of descent for man and the apes. But it was made sufficiently plain, and the public laid hold of the point eagerly, that the doctrine of descent was not meant to exclude man from the field of its operation. Huxley, in the course of his ordinary work as Professor of Biology, had, among many other subjects, naturally turned his attention to the anatomy and classification of the higher animals. When Owen's essay appeared, he found that he was unable to agree with many of the conclusions contained in it, and had set about a renewed investigation of the matter. Thus it happened that, when the question became prominent, in 1860, Huxley was ready with material contributions to it. He believed, moreover, that, as Darwin was not specially acquainted with the anatomy and development of vertebrates, there was an opportunity for doing a real service to the cause of evolution. Accordingly, in 1860, he took for the subject of a series of lectures to workingmen the "Relation of Man to the Lower Animals," and, in 1862, expanded the lectures into a volume called Man's Place in Nature. When it was ready, he was prepared to say with a good conscience that his conclusions "had not been formed hastily or enunciated crudely."

"I thought," he wrote in the preface to the 1894 edition, "I had earned the right to publish them, and even fancied I might be thanked, rather than reproved, for so doing. However, in my anxiety to promulgate nothing erroneous, I asked a highly competent anatomist and very good friend of mine to look through my proofs, and, if he could, point out any errors of fact. I was well pleased when he returned them without any criticism on that score; but my satisfaction was speedily dashed by the very earnest warning, as to the consequences of publication, which my friend's interest in my welfare led him to give; but, as I have confessed elsewhere, when I was a young man there was just a little—a mere soupcon—in my composition of that tenacity of purpose which has another name, and I felt sure that all the evil things prophesied would not be so painful to me as the giving up of that which I had resolved to do, upon grounds which I conceived to be right. So the book came out, and I must do my friend the justice to say that his forecast was completely justified. The Boreas of criticism blew his hardest blasts of misrepresentation and ridicule for some years; and I was even as one of the wicked. Indeed, it surprises me, at times, to think how anyone who had sunk so low could have emerged into, at any rate, relative respectability."

Further, in the same preface, Huxley strongly advises others to imitate his action in this matter. There are now, and no doubt there always will be, truths "plainly obvious and generally denied." Whoever attacks the current ideas is certain, unless human nature changes greatly, to encounter a bitter opposition, and there will always be those among his friends who recommend him to temper truth by prudence. Huxley's advice is different:

"If there is a young man of the present generation who has taken as much trouble as I did to assure himself that they are truths, let him come out with them, without troubling his head about the barking of the dogs of St. Ernulphus. Veritas praevalebit—some day; and, even if she does not prevail in his time, he himself will be all the better and wiser for having tried to help her. And let him recollect that such great reward is full payment for all his labour and pains."

Although they were written so long ago, the lectures on "Man's Place in Nature" are still the best existing treatise on the subject, and we shall give an outline of them, mentioning the chief points in which further work has been done. Information concerning the man-like apes was scattered in very different places, in the grave records of scientific societies, in the letters of travellers and missionaries, in the reports of the zooelogical societies which had been in possession of living specimens. The facts had to be sifted out from a great mass of verbiage and unfounded statement. With a characteristic desire for historical accuracy, more usual in a man of letters than in an anatomist, Huxley began with a study of classical and mediaeval legends of the existence of pigmies and man-like creatures; but, while recognising that legends of satyrs and fauns were presages of the discovery of man-like apes, he was unable to find any actual record earlier than that contained in Pigafetta's Description of the Kingdom of Congo, drawn up from the notes of a Portuguese sailor and published in 1598. The descriptions and figures in this work apparently referred to chimpanzees. From this date onwards he traces the literature of the animals in question, and then proceeds to give an account of them.

There are four distinct kinds of man-like apes: in Eastern Asia the Orangs and the Gibbons (although some later writers differ from Huxley in removing the Gibbons from the group of anthropoids); in Western Africa, the Chimpanzees and the Gorillas. All these have certain characters in common. They are inhabitants of the old world; they all have the same number of teeth as man, possessing four incisors, two canines, four premolars, and six true molars in each jaw, in the adult condition, while the milk dentition, as in man, consists of twenty teeth,—four incisors, two canines, and four molars in each jaw. Since Huxley wrote, a large bulk of additional work upon teeth has been published, and we now know that man and the anthropoid apes display the same kind of degenerative specialisation in their jaws. Simpler and older forms of mammals had a much larger number of teeth, and these differed among themselves more than the teeth of the higher forms. In the Anthropoids and Man, the jaws are proportionately shorter and less heavy than in simpler forms, and, in correspondence with this, the number of the teeth has become reduced, while the teeth themselves tend to form a more even row. The canine or eye-teeth are relatively smaller in the gorilla than in primitive mammals; they are still smaller in the lower races of man; while in ordinary civilised man they do not project above the others. The shortening of the jaw is still proceeding, and, although in lower races of man the last molar or wisdom tooth is almost as large as the molars in front of it, in the higher races the wisdom tooth is much smaller and frequently does not develop at all, or begins to decay very soon after its appearance. If the process of extinction of lower races were to proceed much further, so that civilised white races became the only human inhabitants of the earth, then the gap between the Anthropoids and Man would be wider than it now is; man would be characterised by the presence of one tooth less than the anthropoids, just as the anthropoids and some lower monkeys are characterised by having one tooth less than monkeys still lower.

In all, the nostrils have a narrow partition and look downwards as in man. The arms are always longer than the legs, the difference being greatest in the orang and least in the chimpanzee. We know now that in the lower races of man, the arms are proportionately longer than in higher races, and it has recently been shewn that, although there is a general proportion between the length of the long bones and the height of the whole body in man, so that the height may be calculated with an average error from these bones, yet the probable error is greater when the calculation is made from the arms than when it is made from the legs. In fact, the length of arm as compared to the length of leg and to whole height is a more variable feature in man than the length of leg.

In all the anthropoids, the forelimbs end in hands with longer or shorter thumbs, and the great toe, always smaller than in man, is far more movable and can be opposed like a thumb to the other toes. Since Huxley wrote, a considerable amount of evidence has been collected shewing that partial opposability of the toe in man is not uncommon, and that there is evidence as to a tendency to increase of length of the great toe within historical times. None of the great apes have tails, and none of them have the cheek pouches common among lower monkeys.

Huxley then gives an account of the natural history of these animals, an account which still remains the best in literature. He sums up the habits of the Asiatic forms as follows:

1. They may readily move along the ground in the erect, or semi-erect position, and without direct support from the arms.

2. They may possess an extremely loud voice, so loud as to be readily heard one or two miles.

3. They may be capable of great viciousness and violence when irritated; and this is especially true of adult males.

4. They may build a nest to sleep in.

He finds the same general characters in the case of the gorilla and chimpanzee, but in their case there was not quite so reliable evidence upon which to go.

Although, since Huxley wrote, there has been much greater opportunity of studying anthropoid apes, both in confinement and in their native haunts, there is not much to add to his account. Some little time ago, the world was interested by the assertion of a clever American that he had discovered a kind of language used by the higher apes, and that he was able to communicate with them. Mr. Garnier, the person in question, declared his intention of going out to tropical Africa and establishing himself in a strong cage in the forests inhabited by gorillas and chimpanzees, in the hope that, impelled by curiosity, they would look upon him as we look on monkeys in a zooelogical garden, and that he would thus be able to make his knowledge and records of monkey language more perfect. As a matter of fact he went to Africa, and on his return published a volume which aroused the indignation of naturalists. There was internal evidence that he had gone no further than the garden of a coast station, and his pretended account of the habits of monkeys as they lived in their native haunts contained nothing that was not already known. There is no doubt but that the anthropoid apes, like many other animals, use modulations of their voice to express emotional states; that, in fact, they have love-cries and cries of warning, of alarm, and of pleasure; but there is not the smallest evidence to suppose that in the case of the anthropoids these cries approach more nearly to speech than the cries of any other of the higher mammals.

Since Huxley's volume was published, a large amount of information has been published by Darwin, Romanes, and others upon the mental capacities of anthropoids kept in confinement, and the result of this has been to prove that the anthropoids, in especial the chimpanzees, possess mental powers more akin to those of man than are to be found in the most intelligent of the quadrupeds. We may cite some instances of these higher powers. Vosmaern had a tame female orang-outang that was able to untie the most intricate knot with fingers or teeth, and took such pleasure in doing it that she regularly untied the shoes of those who came near her. The female chimpanzee called Sally, that lived for many years in the Zooelogical Society's Gardens in London, was taught by its keeper and by Romanes an interesting variety of "tricks" involving at least the rudiments of what may be called human intelligence. Among other feats, it would pick up from the floor and present to the keeper or to a visitor, a stated number of straws up to five. Many monkeys seem nearly purely destructive in their dealings with objects within their reach; but Leutemann tells of an orang-outang which "tried to put to its proper use whatever was given to him. To my great surprise he attempted to put on a pair of gloves. He supported himself on a light walking cane and, when it bent under him, made ridiculous motions to right it again." Brehm tells of a chimpanzee:

"After eating, he at once begins to clean up. He holds a stick of wood in front of him, or puts his hands in his master's slippers, and slides about the room, then takes a cloth and scrubs the floor. Scouring, sweeping, and dusting are his favourite occupations; and, when he once gets hold of the cloth, he never wants to give it up."

Falkenstein has given a detailed description of a gorilla which was remarkable for his delicacy in eating.

"He would take a cup or glass with the greatest care, using both hands to carry it to his mouth, and setting it down so carefully that I do not remember having lost a single piece of crockery through him, though we had never tried to teach him the use of such vessels, wishing to bring him to Europe as nearly in his natural condition as possible."

These and a multitude of similar observations which have been made since Huxley wrote are typical of the increase of our knowledge on the habits and capacities of the anthropoid apes. They all serve to show that in them the instinct for experimental investigation of everything with which they are surrounded, and their imitative faculties are peculiarly great. The importance of this, from the point of view of Huxley's argument, is great. The difference between the instincts of the lower animals and the intelligence of man is that instincts are to a large extent fixed and mechanical. The proper performance of an instinct demands the presence of exactly the right external conditions for its accomplishment. In the absence of these conditions, the call to perform the instinctive action is equally great, and results in useless performances. In many of the higher animals these elaborate instincts are more general in their character, and are supplemented by a considerable but varying aptitude for modification of instinctive action to suit varieties of surrounding circumstances. As this intelligence becomes more and more developed, the blind, mechanical instinct becomes weaker. A large number of instances might be given of such instincts modified by dawning intelligence. The chief factors in producing the change are, as has been shewn by Professor Groos, the possession of a general instinct to imitate and to experiment, and the existence of a period of youth in which the young creature may practise these instincts, and so prepare itself for the more serious purposes of adult life. The anthropoid apes seem to possess these experimental instincts to an extent much greater than that observed in any other class of animals, and, as they have a long period of youth, they have the opportunity of putting them into practice to the fullest possible extent.

From the natural history of the anthropoid apes, Huxley passed to consideration of their relation to man, prefacing his observations with a passage defending the utility of the enquiry, a passage necessary enough in these days of prejudice, but now chiefly with historical interest:

"It will be admitted that some knowledge of man's position in the animate world is an indispensable preliminary to the proper understanding of his relations to the universe; and this again resolves itself in the long run into an enquiry into the nature and the closeness of the ties which connect him with those singular creatures whose history has been sketched in the preceding pages.

"The importance of such an enquiry is, indeed, intuitively manifest. Brought face to face with these blurred copies of himself, the least thoughtful of men is conscious of a certain shock; due perhaps not so much to disgust at the aspect of what looks like an insulting caricature, as to the awakening of a sudden and profound mistrust of time-honoured theories and strongly rooted prejudices regarding his own position in nature, and his relations to the underworld of life; while that which remains a dim suspicion for the unthinking, becomes a vast argument, fraught with the deepest consequences, for all who are acquainted with the recent progress of the anatomical and physiological sciences."

Huxley then proceeded to elaborate the argument from development for the essential identity of man and the apes. This argument has now become more or less familiar to us all, as it has gained additional support from recent extension of embryological knowledge, and as it has been used in every work on evolution since Huxley first laid stress on it. The adult forms of animals are much more complex than their embryonic stages, and the series of changes passed through in attaining the adult condition make up the embryological history of the animal. Huxley took the embryology of the dog as an example of the process in the higher animals generally, and as it had been worked out in detail by a set of investigators. The dog, like all vertebrate animals, begins its existence as an egg; and this body is just as much an egg as that of a fowl, although, in the case of the dog, there is not the accumulation of nutritive material which bloats the egg of the hen into its enormous size. Since Huxley wrote, it has been shewn clearly that among the mammalian animals there has been a gradual reduction in the size of the egg. The ancestors of the mammals laid large eggs, like those of birds or reptiles; and there still exist two strange mammalian creatures, the Ornithorhynchus and Echidna of Australia, which lay large, reptilian-like eggs. The ancestors of most living mammalia acquired the habit of retaining the eggs within the body until they were hatched; and, as a result of this, certain structures which grow out from the embryo while it is still within the egg and become applied to the inner wall of the porous shell for the purpose of obtaining air, got their supply of oxygen, not from the outer air, but from the blood-vessels of the maternal tissues. When this connection (called the placenta) between embryo and mother through the egg-shell became more perfect, not only oxygen but food-material was obtained from the blood-vessels of the mother; and, in consequence, it became unnecessary for the eggs to be provided with a large supply of food-yolk. Among existing marsupial animals, which, on the whole, represent a lower type of mammalian structure than ordinary mammals, there is more food-yolk than in ordinary mammals, and less food-yolk than in the two egg-laying mammals. In the ordinary mammals, such as the rabbit, dog, monkey, and man, there is practically no yolk whatever deposited in the egg; the egg is of minute size, and the embryo obtains most of its food from the maternal blood.

The small egg of the mammal divides into a number of cells, which form a hollow sphere; on the upper surface of this the development of organs begins with the formation of a depression which indicates the future middle line of the animal, and is, in fact, the beginning of the nervous system. Under this is formed a straight rod of gelatinous material, the foundation of the vertebral column, and the body of the embryo is gradually pinched off from the surface of the hollow sphere. After tracing the details of this process, Huxley proceeded as follows:

"The history of the development of any other vertebrate animal, lizard, snake, frog or fish, tells the same story. There is always, to begin with, an egg, having the same essential structure as that of the dog; the yolk of that egg always undergoes division, or segmentation, as it is often called; the ultimate products of that segmentation constitute the building materials for the body of the young animal; and this is built up round a primitive groove, in the floor of which a notochord is developed. Furthermore, there is a period in which the young of all these animals resemble one another, not merely in outward form, but in all essentials of structure, so closely, that the differences between them are inconsiderable, while in their subsequent course they diverge more and more widely from one another. And it is a general law, that, the more closely any animals resemble one another in adult structure, the longer and the more intimately do their embryos resemble one another; so that, for example, the embryos of a snake and of a lizard remain like one another longer than do those of a snake and of a bird; and the embryos of a dog and of a cat remain like one another for a far longer period than do those of a dog and a bird; or of a dog and an opossum; or even than those of a dog and a monkey."

This general rule, that the longer the paths of embryonic development of two animals keep identical the more nearly the two animals are related, when Huxley wrote, was founded on a much smaller number of facts than now are known. Since 1860 an enormous bulk of embryological investigation has been published, and the total result has been to confirm Huxley's position in the fullest possible way. A certain number of exceptions have been found, but these exceptions are so obviously special adaptations to special circumstances that their existence only makes the general truth of the proposition more clear. The most common kind of exception occurs when two closely related animals live under very different conditions. For instance, many marine animals have close allies that in comparatively recent times have taken to live in fresh water. The conditions of life in fresh water are very different, especially for delicate creatures susceptible to rapid changes of temperature, or unable to withstand strong currents. Thus most of the allies of the fresh-water crayfish, which live in the sea, lay eggs from which there are soon hatched minute, almost transparent larvae, exceedingly unlike the adult. In the comparatively equable temperature of sea-water, and in the usual absence of strong currents, these small larvae, as Huxley shewed later in his volume on the Crayfish, live a free life, obtaining their own food, and by a series of slow transformations gradually acquire the adult form. In fresh water, however, the delicate larvae would be unable to live, and the mode of development is different. The series of slow transformations is condensed, and takes place almost entirely inside the egg-shell; so that, when hatching occurs, the young crayfish is exceedingly like the adult. Apart from such special cases, it is true that the study of development affords a clear test of closeness of structural affinity.