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LITERARY.

MR DARWIN'S DESCENT OF MAN.

The Descent of Man, and Selections in relation to Sex. By Charles Darwin, M.A., F.R.S., &c. In Two Volumes. Murray.

The positive or scientific mode of thought has within the present generation received a great impulse from three works. The first and most widely influential was Mr Mill's 'Logic,' which, it is hardly too much to say, rescued the science of reasoning from scholastic triflers, and restored it to the Baconian ideal as a subordinate aid in the advance of human knowledge. The second was Mr Maine's 'Ancient Law,' which impressed on all who read it a profound sense of the value of the historical method of studying questions regarding the nature and condition of man. The third was Mr Darwin's 'Origin of Species,' which substituted in natural history the profound conception of evolution for a mere catalogue or enumeration of species held together by a slender metaphysical or theological fiction. This was followed up by a detailed application to the fertilisation of orchids, and the case of animals and plants under domestication. It was of course obvious from the beginning that the principle of natural selection could not be restricted to the lower animals, and Mr Darwin has now, in the volume before us, examined the arguments against the extension of his theory to "the paragon of animals." The conclusion at which he arrives is not agreeable to the "natural man;" it offends, or seems to offend, that sense of dignity which redeems the lowest savages from mere animalism, and which ever remains the most precious safeguard of virtue. No objection is felt to the degradation of men into animals, but the reverse operation is bitterly resented. In the Timœus, Plato tells us that men who were guilty of cowardice and injustice were, after death, turned into women; harmless but superficial men were changed into birds; those who in their lifetime made gods of their bellies passed into the more brutal land animals; the stupid men became fishes. Such is the teaching of imagination prompted by vanity; science holds forth a different but not less elevating conception.

To believe that man was aboriginally civilised, and then suffered utter degradation in so many region's, is to take a pitiably low view of human nature. It is apparently a truer and more cheerful view that progress has been much more general than retrogression; that man has risen, though by slow and interrupted steps, from a lowly condition to the highest standard as yet attained by him in knowledge, morals, and religion.

Every attempt that has been made to discover in the bodily structure of man any impassable barrier separating him from other animals has utterly failed. The scientific world has not forgotten the sharp contest about the Hippocampus minor; but it is admitted, even by hostile witnesses, that "every chief fissure and fold in the brain of man has its analogy in that of the orang." The human embryo is distinguishable from the young ape only in the later stages of its growth. The points of resemblance between man and other animals are numerous; but there is one class of cases singularly instructive, namely, the presence of useless, rudimentary organs, the representatives of which are found in useful activity in other animals. No one can doubt that the rudimentary legs of snakes, which are of no use to them, indicate their descent from animals by whom those extremities were employed in locomotion. The ears of most animals are mobile, but those of man are fixed, as is also the case with the chimpanzee and orang. But a more striking peculiarity in the ear of man has been pointed out by the celebrated sculptor, Mr Woolner. He observed in the ears of various monkeys and men a little blunt point, projecting from the inwardly-folded margin of the external ear. According to Mr Darwin, this is a vestige of pointed ears, when the point has been folded inwards. The intermediate stage is actually observed in Ateles beelzebuth. Slight anatomical facts like those are often more useful in classification than broad outstanding differences. "In man the frontal bone consists of a single piece; but in the embryo and in children, and in almost all the lower mammals, it consists of two pieces separated by a distinct suture." Occasionally, in the adult, the separation is kept up, and, what is strangely inexplicable if we reject evolution, more commonly in the crania of extinct races. A large collection of similar facts is given by Mr Darwin, showing, much as we may resent the suggestion, that the higher animals are "bone of our bone, and flesh of our flesh."

One of the least agreeable marks of our similarity in physical structure to the animals is our subjection to the law of population. If thirty millions were to increase at the rate attained in the United States, namely, doubling in twentyfive years, they would in 657 years cover the globe to such an extent that four men would have to stand on each square yard of surface. Although it is probable that barbarous races are less productive than the civilised races, yet they increase far more rapidly than they find desirable. The hill-tribes of India have recently, since their internecine warfare has been put down and vaccination introduced, increased to an extraordinary extent. Among savages, the principal mode of checking the excess of births is infanticide. It formerly prevailed nearly all over the world. Even the "divine Plato" did not see anything improper in resorting to it as a means of getting rid of children who might be expected to grow into weaklings. Low as the state of society is in which infanticide is a normal mode of relief, it is infinitely superior to the condition of the lower animals, who allow the useless mouths to grow up, afterwards to perish. It is a step in the growth of self-control, and leads to the more humane practice of celibacy in a more advanced social stage.

It may be said, however, that it is "mind that makes the man," and that, notwithstanding his external similitude to the brutes that perish, man is "only a little lower than the angels," and therefore to be placed in a totally different category from the rest of the animal kingdom. This objection Mr Darwin has examined in two chapters of the greatest interest, because he approaches the subject not with any à priori, foregone conclusion, but with the experience and knowledge of a profound naturalist solicitous merely to ascertain the truth. The popular rationale of the distinction between man and the lower animals is expressed by the antithesis of reason and instinct. Although it is true that man has fewer instincts than the animals, the difference is one of degree, and not of kind. Many things are attributed to instinct which may be the result of experience. Monkeys avoid the poisonous fruits of the tropics, but our domestic animals often eat poisonous herbs till they learn from their pernicious effects to avoid them. On some farms there are peculiar poisonous herbs that are fatal to most cattle freshly introduced into the farm, so that the stock has to be kept up by breeding from those that have learned to avoid the dangerous herbs. Mr Darwin well observes: "It is a significant fact that the more the habits of any particular animal are studied by a naturalist, the more he attributes to reason and the less to unlearnt instincts." All the common emotions are shared by animals as well as men. A dog shows jealousy of his master's affection; it loves praise and even feels shame. It is stated that monkeys dislike being laughed at. Mr Darwin mentions a curious fact:

In the Zoological Gardens I saw a baboon who always got into a furious rage when his keeper took ont a letter or book, and read it alond to him; and his rage was so violent that, as I witnessed on one occasion, he bit his own leg till the blood flowed.

That animals can reason, and can invent original device, is evident to any one who has watched their habits. An example given by Mr Darwin illustrates this:

Mr Colqnhonn winged two wild docks, which fell on the opposite side of a stream; his retriever tried to bring over both at once, but conld not succeed; she then, though never before known to ruffle a feather, deliberately killed one, brought over the other, and returned for the dead bird.

There are few who could not give similar instances. In one case, where a ball was accidentally thrown into a pond, a little Scotch terrier was sent in by its master to fetch it out. The ball was rather large, and after many trials the dog failed to take the ball in its mouth, and was returning without it. On being sent back it deliberated, and then began to push the ball before it in the water, and thus took it to land. Such a stroke of invention differs in nothing but degree from the great feats of human ingenuity; and it is not saying too much that, if allowance be made

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for the vast superiority of the mental power of man, there are not many human beings capable of distinguishing themselves more than the little terrier.

Various other criteria have been proposed to establish a line of demarcation, such as that man is the only progressive animal, or that he alone possesses language, or has self-consciousness, or a sense of beauty, or any religion; but those alleged peculiarities (except the last-mentioned) are all found, in some degree, in the lower animals, and the last, besides being dependent on other faculties, is not shared by all men. Mr Darwin says:

We could never discover that the Fuegians believed in what we should call a God, or practised any religious rites; and Jemmy Button (a Fuegian on board the Beagle), with justifiable pride, Stoutly maintained that there was no devil in his land.

The distinction most relied on is conscience. Animals do not discriminate between right and wrong; they exhibit prudence, and may be acted on by fear, but they have no moral sense. To those who believe that conscience is a unique faculty, the difficulty must, no doubt, be considerable of imagining by what steps it could have been developed. Rather it must have come all at once, uno ictu, as a divine inspiration, and could not have been elaborated, since it is itself elementary and incapable of being analysed or resolved into simpler components. At this point, therefore, a naturalist, who accepts the theory of evolution, is compelled to leave, for a time, the concrete, visible facte with which he is accustomed to deal, and follow the metaphysical moralist through all the mazes of ethical controversy. Mr Darwin's discussion of this thorny question indicates, as might have been expected, a greater leaning towards Mr Herbert Spencer than to Mr Mill or Professor Bain, although not so great as Mr Darwin himself seems to suppose. The chief moment or factor of conscience, according to Mr Darwin, is the social instinct which leads animals to take pleasure in the society of their fellows, "to feel a certain amount of sympathy with them, and to perform various services for them." This instinct is shared in by many animals, conspicuously by the monkeys, regarding whom many curious instances are produced. One example may be given from the birds:

Captain Stansbury found on a salt lake in Utah an old and completely blind pelican, which was very fat, and must have been long and well fed by his companions.

But whence comes the supremacy of conscience? why should it set up a claim to domineer over all the other instincts? Because it is always with us, whereas the other instincts give brief pleasure, and when out of sight are out of mind. Thus any violence done to the social instinct continues to give pain long after the temptation has disappeared, and the momentary gratification is forgotten. Perhaps the most powerful instinct in a bird is the maternal, but it yields to the migratory instinct. "When arrired at the end of her long journey, and the migratory instinct ceases to act, what an agony of remorse each bird would feel, if, from being endowed with great mental activity, she could not prevent the image continually passing before her mind of her young ones perishing in the bleak north from cold and hunger." The whole chapter is of great interest; it traces the analogy between the social animals and man very closely and instructively.

The conclusion to which Mr Darwin comes is the same as that expressed by Professor Huxley, "that man in all parts of his organisation differs less from the higher apes than these do from the lower members of the same group." It is probable that man originated from an ancient member of the sub-group of anthropomorphous apes, the representatives of which now are the gorilla, chimpanzee, orang, and hylobate. Man may have diverged from the stock so far back as the Eocene period. He is related to the gorilla, not as a grandson or great grandson, but as a grand-nephew or great grand-nephew, or perhaps as a distant cousin. We shall not pursue the genealogy farther; but it may be observed that Mr Darwin speculates with his usual ingenuity and sagacity on the probable line of descent. It may, however, not be uninteresting to quote his "restoration" of our forefathers:

The early progenitors of man were no doubt once covered with hair, both sexes having beards; their ears were pointed and capable of movement, and their bodies, were provided with a tail having the proper muscles. Their limbs and bodies were also acted on by many muscles which now only occasionally reappear, but are normally present in the Quadrumana. The great artery and nerve of the humerus ran through a supra-condyloid foramen. At this or some earlier period, the intestine gave forth a much larger diverticulum or cæcum than that now existing. The foot judging from the condition of the great toe in the fœtus was then prehensile; and our progenitors, no doubt, were arboreal in their habits, frequenting some warm, forest-clad land. The malas were provided with great canine teeth, which served them as formidable weapons.

Our notice of the second part of Mr Darwin's book, on "Sexual Selection," must be reserved for another article.