Now no one disputes as to birds showing preferences one for another, but it is quite a gratuitous suggestion that the pied plumage of the venerable paterfamilias was the charm which attracted the opposite sex; and even if such were the case, it would seem (from Mr. Darwin's concluding remark) to prove either that the peahen's taste is so different from ours, that the peacock's plumage could never have been developed by it, or (if the taste of these peahens was different from that of most peahens) that such is the instability of a vicious feminine caprice, that no constancy of coloration could be produced by its selective action.

Mr. Darwin bases his theory of sexual selection greatly on the fact that the male birds display the beauty of their plumage with elaborate parade and many curious and uncouth gestures. But this display is not exclusively used in attracting and stimulating the hens. Thus he admits that 'the males will sometimes display their ornaments when not in the presence of the females, as occasionally occurs with the grouse at their balz-places, and as may be noticed with the peacock; this latter bird, however, evidently wishes for a spectator of some kind, and will show off his finery, as I have often seen, before poultry or even pigs' (vol. ii. p. 86). Again, as to the brilliant Rupicola crocea, Sir R. Schomburgk says: A male was capering to the apparent delight of several others' (vol. ii. p. 87).

From the fact of 'display' Mr. Darwin concludes that 'it is obviously probable that the females appreciate the beauty of their suitors' (vol. ii. p. 111). Our Author, however, only ventures to call it 'probable,' and he significantly adds: 'It is, however, difficult to obtain direct evidence of their capacity to appreciate beauty.' And again he says of the hen bird: It is not probable that she consciously deliberates; but she is most excited or attracted by the most beautiful, or melodious, or gallant males' (vol. ii. p. 123). No doubt the plumage, song, &c., all play their parts in aiding the various processes of life; but to stimulate the sexual instinct, even supposing this to be the object, is one thing -to supply the occasion for the exercise of a power of choice is quite another. Certainly we cannot admit what Mr. Darwin affirms (vol. ii. p. 124), that an 'even occasional preference by the female of the more attractive males would almost certainly lead to their modification.'

A singular instance is given by Mr. Darwin (vol. ii. p. 111) in support of his view, on the authority of Mr. J. Weir. It is that of a bullfinch which constantly attacked a reed-bunting, newly put into the aviary; and this attack is attributed to a sort of jealousy on the part of the blackheaded bullfinch of the black

head

head of the bunting. But the bullfinch could hardly be aware of the colour of the top of its own head!

Mr. Wallace accounts for the brilliant colours of cater

a

pillars and many birds in another way. The caterpillars which are distasteful must have gained if some outward sign indicated to their would-be destroyer that its prey was disgusting morsel.' As to birds, he believes that brilliance of plumage is developed where not hurtful, and that the generally more sober plumage of the hens has been produced by natural selection, killing off the more brilliant ones exposed during incubation to trying conditions.

Now as Mr. Wallace disposes of Mr. Darwin's views by his objections, so Mr. Darwin's remarks tend to refute Mr. Wallace's positions, and the result seems to point to the existence of some unknown innate and internal law which determines at the same time both coloration and its transmission to either or to both sexes. At the same time these authors, indeed, show the harmony of natural laws and processes one with another, and their mutual interaction and aid.

It cannot be pretended that there is any evidence for sexual selection except in the class of Birds. Certain of the phenomena which Mr. Darwin generally attributes to such selection must be due, in some other classes, to other causes, and there is no proof that sexual selection acts, even amongst birds.

But in other classes, as we have seen, sexual characters are as marked as they are in the feathered group. Mr. Darwin, indeed, argues that birds select, and assumes that their sexual characters have been produced by such sexual selection, and that, therefore, the sexual characters of beasts have been similarly evolved. But we may turn the argument round and say that sexual characters not less strongly marked exist in many beasts, reptiles, and insects, which characters cannot be due to sexual selection; that it is, therefore, probable the sexual characters of birds are not due to sexual selection

either, but that some unknown internal cause has equally operated in each case. The matter, indeed, stands thus: Of animals possessing sexual characters there are some in which sexual selection cannot have acted; others in which it may possibly have acted; others again in which, according to Mr. Darwin, it has certainly acted. It is a somewhat singular conclusion to deduce from this that sexual selection is the one universal cause of sexual characters, when similar effects to those which it is supposed to cause take place in its absence.

But, indeed, what are the data on which Mr. Darwin relies as regards birds? As before said, they are 'display' by the males,

males, the 'greater brilliancy and ornamentation of these,' and the occasional preference' by females in confinement for particular males. Is there here any sufficient foundation for such a superstructure? In the first place, in insects, e. g. butterflies, we have often many brilliant males crowding in pursuit of a single female. Yet, as Mr. Wallace justly observes, 'Surely the male who finally obtains the female will be either the most vigorous, or the strongest-winged, or the most patient-the one who tires out or beats off the rest.' Similarly in birds strength and perseverance will, no doubt, generally reward the suitor possessing those qualities. Doubtless, also, this will generally be the most beautiful or most melodious; but this will simply be because extra beauty of plumage, or of song, will accompany supereminent vigour of constitution and fulness of vitality. What has been before said as to the fierce combats of cockbirds must be borne in mind.

But that internal spontaneous powers are sufficient to produce all the most varied or bizarre sexual characters which any birds exhibit, is actually demonstrated by the class of insects, especially caterpillars which from their sexless undeveloped state can have nothing to do with the kind of selection Mr. Darwin advocates. Yet amongst caterpillars we not only find some ornamented with spots, bands, stripes, and curious patterns, 'perfectly definite in character and of the most brilliantly contrasted hues. We have also many ornamental appendages; beautiful fleshy tubercles or tentacles, hard spines, beautifully coloured hairs arrangèd in tufts, brushes, starry clusters, or long pencils, and horns on the head and tail, either single or double, pointed or clubbed.' Mr. Wallace adds, Now if all these beautiful and varied ornaments can be produced and rendered constant in each species by some unknown cause quite independent of sexual selection, why cannot the same cause produce the colours and many of the ornaments of perfect insects;'-we may also add, the colours and ornaments of all other animals, including birds?

There is, however, another reason which induces Mr. Darwin to accept sexual selection; and it is probably this which, in his mind, mainly gives importance to the facts mentioned as to the plumage and motions of birds. He says of display,' 'It is incredible that all this display should be purposeless' (vol. ii. p. 399); and again (vol. ii. p. 93), he declares that any one who denies that the female Argus pheasant can appreciate the refined beauty of the plumage of her mate, will be compelled to admit that the extraordinary attitudes assumed by the male during the act of courtship, by which the wonderful beauty of his plumage

is fully displayed, are purposeless; and this is a conclusion which I for one will never admit.' It seems then that it is this imaginary necessity of attributing purposelessness to acts, which determines Mr. Darwin to attribute that peculiar and special purpose to birds' actions which he does attribute to them. But surely this difficulty is a mere chimæra. Let it be granted that the female does not select; yet the display of the male may be useful in supplying the necessary degree of stimulation to her nervous system, and to that of the male. Pleasurable sensation, perhaps very keen in intensity, may thence result to both. There would be no difficulty in suggesting yet other purposes if we were to ascend into higher speculative regions. Mr. Darwin has given us in one place a very remarkable passage; he says::

With respect to female birds feeling a preference for particular males, we must bear in mind that we can judge of choice being exerted, only by placing ourselves in imagination in the same position. If an inhabitant of another planet were to behold a number of young rustics at a fair, courting and quarrelling over a pretty girl, like birds at one of their places of assemblage, he would be able to infer that she had the power of choice only by observing the eagerness of the wooers to please her, and to display their finery.'-vol. ii. p. 122.

Now here it must be observed that, as is often the case, Mr. Darwin assumes the very point in dispute, unless he means by 'power of choice' mere freedom of physical power. If he means an internal, mental faculty of choice, then the observer could attribute such power to the girl only if he had reason to attribute to the rustics an intellectual and moral nature similar in kind to that which he possessed himself. Such a similarity of nature Mr. Darwin, of course, does attribute to rational beings and to brutes; but those who do not agree with him in this would require other tests than the presence of ornaments, and the performance of antics and gestures unaccompanied by any evidence of the faculty of articulate speech.

Such, then, is the nature of the evidence on which sexual selection is supposed to rest. To us the action of sexual selection scarcely seems more than a possibility, the evidence rarely raising it to probability. It cannot be a sufficient cause' to account for the phenomena which it is intended to explain, nor can it even claim to be taken as a vera causa at all. Yet Mr. Darwin again and again speaks as if its reality and cogency were indisputable.

As to the alleged action of natural selection on our own species we may mention two points.

First, as to the absence of hair. This is a character which Mr. Darwin admits cannot be accounted for by 'natural selec

tion,' because manifestly not beneficial; it is therefore attributed to 'sexual selection,' incipient man being supposed to have chosen mates with less and less hairy bodies; and the possibility of such action is thought by Mr. Darwin to be supported by the fact that certain monkeys have parts of the body naked. Yet it is a fact that the higher apes have not this nakedness, or have it in a much smaller degree.

Secondly, as to the races of mankind, Mr. Darwin's theory, indeed, requires the alternation of constancy and caprice to account for the selection and the conservation of marked varieties. In order that each race may possess and preserve its own ideal standard of beauty we require the truth of the hypothesis that certain tastes may in the course of time become inherited ;' and yet Mr. Darwin candidly admits (vol. ii. p. 353): 'I know of no evidence in favour of this belief.' On the other hand, he says (p. 370), As soon as tribes exposed to different conditions came to vary, each isolated tribe would form for itself a slightly different standard of beauty,' which would gradually and inevitably be increased to a greater and greater degree.' But why have not the numerous tribes of North American Indians diverged from each other more conspicuously, inhabiting, as they do, such different climates, and surrounded by such diverse conditions?

Again, far from each race being bound in the trammels of its own features, all cultivated Europeans, whether Celts, Teutons, or Slaves, agree in admiring the Hellenic ideal as the highest type of human beauty.

We may now pass on to the peculiarities of man's bodily frame, and the value and signification of the resemblances presented by it to the various structures which are found to exist in lower members of the animal kingdom.

Mr. Darwin treats us to a very interesting account, not only of man's anatomy, but also of the habits, diseases, and parasites (internal and external) of man, together with the process of his development. He points out (vol. i. p. 11) not only the close similarity even of cerebral structure between man and apes, but also how the same animals are liable to many of the same non-contagious diseases as we are; thus Rengger, who carefully observed for a long time the Cebus Azara in its native land, found it liable to catarrh, with the usual symptoms, and which when often recurrent, led to consumption. These monkeys suffered also from apoplexy, inflammation of the bowels, and cataract in the eye. The younger ones, when shedding their milk-teeth, often died from fever. Medicines produced the same effect on them as on us. Many