ficial to an internal and very forcible characteristic. The smooth skin is an obvious and striking peculiarity of man; but if anyone were asked what above all else made him what he is, he would probably reply, the brain. Let us see, then, if it seems likely that the human brain was developed by natural selection from the brute brain. The size of the human brain is, in comparison with that of all other animals, enormous. This superiority in magnitude, accompanied as it is by certain other less obvious and less indisputable marks of difference, seemed to Professor Owen sufficient to justify him in placing man in a class by himself—that of Archencephala, or chief-brained animals. The average brain of the highest anthropoid apes-the orang-utan or the gorilla-does not reach above 28 or 30 cubic inches, while the average internal capacity of the cranium in the Teutonic family of man amounts to 94 cubic inches. The difference is enormous; but if we could trace the growth of that difference step by step from one to the other, and see how at every step the owner of the larger brain would gain thereby an advantage over the smaller, there would be nothing in this difference to take it out of the ordinary action of natural selection. If the primitive flintchippers had brains not much larger than apes, if those of the modern savages were a little bigger still, and if, as we travelled towards the civilised and intellectual periods of history, we found the brain steadily increasing, the change would be in full accordance with other illustrations of the law. But what is the case? So far as investigation has yet gone, there is no great difference in the average cranial capacity of man under any circumstances. That of the Esquimaux is 91 cubic inches, of the Negro 85, of the Australians and Tasmanians 82, while even that of the Bushman-the lowest specimen of living humanity with which we are acquainted-is 77. Nor do the few skulls of the earlier races, which have yet been discovered, tell any different tale. The celebrated Engis skull, which was probably contemporary with the mammoth and the cave bear, has been pronounced by Professor Huxley to be "a fair average skull, which might have belonged to a philosopher, or might have contained the thoughtless brains of a savage." But the brains of any ape would have lain in a corner of it, and left a large vacancy. If the ape passed into the savage, the change in the brain was made by a leap. Now is there anything to make such a leap likely? Is there anything in this enormous increase of brain which would give its possessor an advantage over smaller brains, and enable him to survive while they perished? No doubt a larger brain has an advantage over a smaller one. The brain is the organ of the greatest power that we know-the power of mind. It is the

A man

seat of thought, intelligence, sensation, emotion, will. who owns these mighty implements in larger measure than his fellows has no doubt a great advantage over them in the struggle for existence, if he uses them. But they are no good to him in this respect while they lie latent or unused. does not become a match for a wild beast because he has a spear laid up in his armoury at home. The spear must be in his hand, and driven by strong muscles into the heart of his foe, to be of any use to him. So it is with the mental faculties. Just so much as a man uses of them would become the object of natural selection, and no more. All the surplusage goes for nothing in the battle of life. The largest gorilla brain that has yet been measured contains 34 cubic inches. Probably mental power depends on some other conditions besides the mere size of the brain, and therefore we should not be justified in saying that a creature with 35 inches of brain would certainly beat this gorilla. But we know that size is a principal factor in the problem, and we may therefore say very confidently that 40 inches of brain would answer this purpose. How, then, does it happen that the lowest savage has more than 70? Natural selection might secure him the 40, because apes with less brain would be crushed out to make room for him; but how would he get or keep the additional 30? If an individual chanced to be born, a mere monstrosity, with this huge addition to the normal quantity of his kind, what likelihood would there be of its being perpetuated? He would be simply in the condition of the moth with its proboscis an inch longer than was required for any useful purpose, and the sure result-if natural selection were the only power that acted upon it would be the rapid reversion of his descendants to the ordinary type.

But, it may be asked, is all this brain so much surplusage in the savage? Are we justified in assuming that the greater portion of it lies dormant ? Are we sure that he does not use it all, and that, in this use of it, there does not lie the secret of his superiority over the brutes around him, and the germ of that dominion over the whole creation which seems to be the goal to which he is continually tending? The only answer to this can be found in the comparison of the savage as regards the action of mind, on the one hand, with the highest of the brutes beneath, and, on the other, with the civilised man above him. If the difference in the amount of brain corresponds in these three gradations with the difference in mental development, the inference would be that the whole brain was used in each case. If this correspondence does not exist, it will follow that the brain is unused in any case in the degree in which the mental development in that case falls short of its required

proportion. Now the average proportions of the brain in the anthropoid apes, in the savage, and in civilised man respectively, may be represented by the figures 10, 26, and 32. Is this a true representation of the mental conditions of the three? Is the difference between the savage and the brute really more than twice as great as that between the savage and the educated European? Mr. Wallace bids us think of the difference in mathematical power between a senior wrangler and an average Englishman, and then descend from that to the condition of a savage who cannot count beyond three or five-of the mental wealth and vigour implied in forming abstract ideas, carrying on chains of complicated reasoning, and transacting the manifold business of law, commerce, and politics in our modern life on the one hand, and of the meagreness and poverty of savage life on the other, wholly given up to the mere necessities of providing daily food-and then say whether the intellectual development of the savage is not much more nearly akin to that of the lower animals around him than to that of the cultivated European. But if so, a large part of his enormous development of brain is simply wasted. He gets no good from it, and therefore there is no reason, on the principle of natural selection, why it should have grown so large. For natural selection can only favour the increase of any particular organ just so far as that increase confers an actual benefit in the struggle for existence. If the increase of the organ outgrows its use, that additional growth is due to some other cause; for natural selection admits no surplusage.

Nor is the size of the brain the only characteristic in man which presents this difficulty. Mr. Wallace applies the same line of argument with great ingenuity to the foot, the hand, the voice, and, above all, the higher mental faculties. All these seem to be perfected and specialised far beyond their actual needs in savage man. The upright gait of man, "godlike erect," the delicate capacities of his hand, the vocal apparatus capable from the first of the exquisite modulations which can only be appreciated by the cultivated ear, the moral sense, the perception of beauty, the abstract conceptions of number and extension-all these seem wholly out of the range of the results that can be accounted for by the preservation of useful variations. They all point in a very different direction, and lead us on to another stage in Mr. Wallace's argument.

For it is remarkable that all those peculiarities, which seem, like the large brain, to be superfluous, or, like the smooth skin, to be positively injurious, to their first possessor, are eminently qualified to lead man on to the heights of being which he has subsequently attained. The smooth skin suggests at once the necessity of clothes; the absence of claws and

talons, combined with the wonderful capacity of the hand, leads naturally to the fabrication of tools and weapons; the vast size of the brain provides a dormant reservoir of intellectual power, out of which every need, as it arises, may be met by a corresponding contrivance of supply. But all these capacities have a reference to the future, and not to the present. In the first instance, we see a creature born into the world weak, undefended, and unsupplied for the moment, but provided with faculties which eminently fit it for a far higher existence in some remote ages and under very different conditions. The capacities are given first; the use of them comes later. They do not arise out of the pressure of past necessity; they are bestowed in anticipation of future wants and for the furtherance of a future development. But that is the method of final causes, which is exactly contradictory to that of natural selection. The former looks always forwards, and the latter looks always backwards. The one is the method of prophecy, and the other of history. The one implies the action of an intelligent and forecasting agent, while the other relies wholly on a chain of causation which may or may not have been established in the first instance by an intelligent agent, but which, once established, works on blindly and unalterably by itself. This may be illustrated by the action of man upon Nature in his own province of artificial selection. When the florist wishes to produce a particular variety of flower or leaf, he carefully selects all individuals that approximate towards it, guards them from injurious influences, secures their inter-breeding, and takes them, in short, by his protecting care out of the natural conditions into which they are born. The pigeon-fancier aiming at a special feather, the poultry-breeder desiring to secure plenty of eggs, the sheep-farmer cultivating specially, as it may happen, wool or mutton, acts in the same way. In all these cases an ideal is first proposed which is afterwards worked up to. The ordinary operations of Nature are defied or counteracted by special contrivance in order that the proposed end may be gained that the intended type of animal may be, so to speak, created. They are all cases, within narrow limits, of final causes, in which man's intelligence is the causer, and the laws of Nature the unintelligent instruments. Natural selection has, in these cases, to bow before the higher power of human selection. The inference which Mr. Wallace draws from the line of thought which he has developed--and it seems the only possible inference-is that some such superior selection has been at work in the production of man. Some higher intelligence has exercised over the world at large the same kind of control which man displays in his farm or in his poultry-yard. This superior intelligence has forced the great life-agencies on the

earth out of their natural course for the sake of producing a choice and eminent creature, just as the florist manipulates his roses to produce a Lamarque or a Maréchal Niel, or a pigeonfancier his birds to bring about a pouter or a fan-tail. Into the further question of what this mighty Life-fashioner may be, or by what other name he may be called, Mr. Wallace does not enter, though we may gather, from a passage in which he speaks of "the controlling action of such higher intelligences," that he does not necessarily identify him with the First Cause of all things, but rather inclines to the view that such interference with the ordinary course of nature may be due to some unknown order of intelligent existences, the existence of which may help to carry our thoughts across the immeasurable chasm which separates man from the Infinite and Unconditioned.

These are thoughts which open vistas of scientific imagination in which even Professor Tyndall might find ample room to range. If we admit them at all, it is scarcely possible to stand still on them. If this overruling and intelligent selection has been necessary to produce man, why should it be limited to that single achievement? A unique and solitary interference of this kind is far more inconsistent with any philosophical view of creation than an habitual and regular guidance. Mr. Wallace himself puts this forcibly when he admits that his theory "has the disadvantage of requiring the intervention of some distinct individual intelligence, to aid in the production of what we can hardly avoid considering as the ultimate aim and outcome of all organized existence-intellectual, ever-advancing, spiritual man.' But the disadvantage vanishes if he will boldly extend his theory, and allow it to include, as he hints in the following sentence, the idea "that the controlling action of such higher intelligences is a necessary part of the great laws which govern the material universe;" or, to put it in other words, that intelligent superintendence is a perpetual factor in the development of life. Other cases, besides man, might easily be brought forward, which present similar difficulties in the way of natural selection, and seem therefore to require the introduction of this other factor. What, for instance, were the steps which led to the production of the first mammal, or of the first vertebrate? It is easy to see the superiority of the perfect animal in either case, and its consequent fitness as an aim towards which intelligence might work, but very difficult to comprehend how the first steps in either direction can have been beneficial to the individual. Some years ago a Scotch clergyman, Mr. Rorison, published a little book, which has hardly been so widely read as it deserved to be, entitled "The Three Barriers." They were the Brain, the Breast, and the Backbone-the symbols of Wisdom,