Most men are not aware of the toil and trouble zoologists have taken to name and number the animals of the earth and to arrange them in groups according to the manner in which their bodies are made. We know the commoner animals as they come before us, but do not trouble about the relationship of one beast to another. As regards man, he seems to us so very different to all the common animal forms that we cannot believe him to be related to them at all, but prefer to regard him as standing isolated and alone, as a being of a peculiar order. When, however, we begin to study his body and compare it, organ by organ, with that of other animals, we see that his isolation disappears, and that it is the thick veil of civilization in which he has so completely hidden himself that misleads us regarding his true position in the animal kingdom. The reader will see that I am preparing his mind for the kind of evidence to be produced in this chapter—evidence as to " Man's place in Nature," as Huxley happily named it in his celebrated book published in 1863. We propose to visit an institution in which Huxley loved to work and to lecture, namely, the Museum of the Royal College of Surgeons of England, situated right in the heart of London on the south side of Lincoln's Inn Fields. The museum has a history; its foundation was laid in the latter half of the eighteenth century by the great surgeon, John Hunter, one of the very greatest men this country has ever produced. He was centuries ahead of his time, and hence he is not yet properly appreciated. The hours he could steal from work and sleep he devoted to the study of all forms of life; but instead of describing on paper what he saw and discovered, he left the actual specimens themselves—all duly preserved, to tell their own stories to future generations. Since his day men like Sir Richard Owen and Sir William Flower have added to and tended Hunter's priceless collection, so that here we can study the evidence afforded by man's body better than anywhere else in the world. Hunter's invariable method was to commence with the simplest and lowest forms of life and work gradually through the more complex which led on to the highest—man himself. As we enter the museum it soon becomes evident that it will answer our present purpose best to reverse Hunter's order, and in each instance commence with the human form.
As we pass through the first and second rooms of the museum we see the skulls and skeletons of all races of mankind, European, Asiatic, American, African and Australian, in case after case, but only the practised eye picks out the peculiar features of each race; as far as the evidence of the skeleton goes mankind appears to be a very uniform species. It is in the third room that the first real break is encountered, where the human series ends and the anthropoid skeletons begin. The skeleton of the gorilla is not at all human in appearance, the great crests on the skull, the massive jaws and face, the long stout arms, the short lower limbs with a thumb-like great toe, seem to assure us that even the most man-like of apes is a long way off from man himself. Yet when we look more closely we see that every bone of man's body is present in the gorilla, they occupy exactly the same place in the skeleton; each bone shows the same leading features; the differences relate merely to proportion, size and detail. When we look at the skull of the young gorilla, before the massive, brute-like crests have appeared, the human resemblance is more marked. In the skulls of the adult chimpanzee, these cranial ridges, which are developed to give attachment to the great muscles of mastication, are much smaller than in the gorilla. In the orang they are intermediate in size. They are much larger in the male than in the female anthropoids. The gorilla and chimpanzee are from Africa; the orang from Borneo and Sumatra. It is thus in the forests of the tropical parts of the earth that we find the animals which most nearly resemble man in structure. There are various races of gorillas, chimpanzees and orangs, just as there are various races of mankind, each race being a native of its own peculiar district or country.
Passing from the cases containing the skulls and skeletons of the three great anthropoids to those in which the small anthropoids—the gibbons—are contained, we note another break in the series, quite as marked as the one between man and the great anthropoids. The head and body are much smaller; there are the same bones set together in the same order but the proportions are different. There are numerous races of gibbons scattered through the forests of the far East, from China in the north to Java in the south. In the series of cases which follow, containing first the skeletons of the many kinds of monkeys of the Old World and then those of the New World, we are made aware of the impossibility of representing animals in their right relationship by grouping them one after another in a single file. To be right, there ought to be a double or a triple file here, one for the Old World monkeys, another for those of America, and an intermediate one for the gibbons. Between the gibbons and the monkeys there is a wider gulf than any we have so far seen, yet we cannot well say the one is higher than the other. In certain features we see that the gibbons are related to the Old-World monkeys, in others to those of the New World; we believe that there must be extinct ancestral gibbons which, did we know them, would show us that these three forms of primates have all arisen from a common stock at a long past period of the world's history. It is the American monkeys which interest us most, because amongst them we find quite small and low forms, such as the marmoset, which takes us a little way towards the kind of animals shown in the museum cases following those containing the monkeys—the lemurs. Between the marmosets and the lemurs, however, is a much wider gap than we have yet tried to cross; we realize that we are passing from one order of animals to another, from the primates to the primatoids. Beyond this point in the animal scale we do not intend to pass. If at first we had seen the skeleton of man placed side by side with that of the tiny marmoset we would have denied that there could be any possibility of a common origin for these two, but when we pass from the one to the other through a series which, while showing many breaks, leads us step by step from the one to the other, we begin to see that the miracle of man's primate origin is not so impossible as it appears at first. We note, too, that the links which we miss most lie, not between man and his nearest allies, but between the gibbon and the monkeys grouped near it.