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Lessons From Nature, as manifested in Mind and Matter. By St. George Mivart, Ph.D., F.R.S., &c., &c. (London: John Murray, 1876.)

(Second Notice.)

Hitherto we have been skirmishing; but in Chapters IX. and X.—on Natural and Sexual Selection—we get into the thick of the battle. In his violent attack on Mr. Darwin's theories our author uses unusually strong language. Not content with mere argument, he expresses "reprobation of Mr. Darwin's views;" and asserts that, although he (Mr. Darwin) has been obliged virtually to give up his theory, it is still maintained by Darwinians with "unscrupulous audacity," and the actual repudiation of it concealed by the "conspiracy of silence." But the reader of Mr. Mivart's book, if he is also acquainted with Mr. Darwin's works, will find it difficult to discover a justification of these harsh terms. If there is one thing more than another for which Mr. Darwin is pre-eminent among modern literary and scientific men, it is for his perfect literary honesty, his self-abnegation in confessing himself wrong, and the eager haste with which he proclaims and even magnifies small errors in his works, for the most part discovered by himself. This is a quality so rare, so admirable, and so truly "moral," in Mr. Mivart's own interpretation of the term, that we regret to find no adequate recognition of it by him; while he makes use of it to damage Mr. Darwin's scientific reputation on the ground that a man who has confessed to so many "over-hasty conclusions and erroneous calculations" should be distrusted in other matters. This is no doubt a telling argument to such of Mr. Mivart's readers as have never read Mr. Darwin's works, while to most of those who are acquainted with them it will appear thoroughly inconclusive. Probably no man living has made so many and such varied original investigations in Biology, involving such an overwhelming multitude of details, and bound together by such an amount of subtle and ingenious reasoning, as Mr. Darwin; and it is almost certain that no other man has promulgated so small a proportion of erroneous facts or proved fallacies. On a careful examination of the passages quoted by Mr. Mivart, as showing that Mr. Darwin has virtually given up his theory but will not acknowledge it, we can find no such admissions. Mr. Darwin, indeed, has repeatedly said that if any complex organ existed which could not possibly have been formed by numerous slight modifications, or if it could be proved that any structure of any one species had been formed for the exclusive good of another species, in either case his theory would, he thinks, absolutely break down. Now, in the five quotations from Mr. Darwin's later writings given by Mr. Mivart, which express modification of opinion or admission of error, none apply in any way to these cases, but to structures which are "neither beneficial nor injurious," or to the causes of variation itself, which were always admitted to be unknown. No one useful character, or such as usually distinguish species from species, has been shown to be due to any other cause than variation guided by natural selection. Mr. Darwin admits that there are unknown laws of development and variation, and certain direct actions of external conditions, which to some extent modify animal forms; but, so far as yet known, these can only be permanently preserved or increased, when useful, by means of natural selection. We are not now discussing whether this view is strictly correct, or whether there are not probably unknown laws determining the lines or directions in which alone natural selection can profitably and permanently act. There may be such, and the present writer is disposed to think there are such; but these have not been proved to exist, while natural selection is admitted by Mr. Mivart himself to be a vera causa, and has been proved to act so widely and so effectually that it may well be considered, as Mr. Darwin and his followers still consider it, the most important agent in the determination and limitation of specific forms.

But if Mr. Mivart, as we think, wholly fails to prove that natural selection holds

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but a subordinate place among the causes which have led to the production of what we term species, he adduces much more cogent arguments against the theory of sexual selection, as developed in Mr. Darwin's great work on the Descent of Man. To that branch of sexual selection which depends on the struggles and combats of male animals, and the development thereby of greater strength and of offensive or defensive weapons, no objection is made; while a powerful array of facts and arguments are brought against that active and special selection by the female which is supposed by Mr. Darwin to be almost the sole cause of the wondrous display of beauty and melody confined to the male sex, and of the larger portion of the beauty that pervades the entire animal kingdom. The subject is far too large and too complicated to admit of discussion here but it may be stated that after again reading carefully Mr. Darwin's chapters on this subject, and considering the mass of facts and arguments he adduces in the light of Mr. Mivart's criticisms, it certainly appears to the present writer that on this important question Mr. Darwin's views are altogether erroneous. It is undoubtedly proved that beauty of various kinds is very largely confined to the male sex, and that in birds, and in some few of the lower animals, this beauty is displayed before the female. There is also some evidence that the female exerts a limited amount of choice, though there is also much in a directly contrary direction; but there is no evidence whatever that this choice is usually determined by small variations in the display. Two or three considerations appear fatal to the theory of the production of the special colours, patterns, and ornaments of the male by the choice of the female, even among birds, where alone there is any evidence on the subject. In the first place, it seems quite incredible, without direct evidence on the point, that a large majority of the females of any species, over the whole area of its range and for many successive generations, should agree in being pleased by the same particular kind of variation. But in addition to this they must also agree in rejecting all other counteracting variations, and also in largely rejecting mates which are a little below the normal standard of beauty; otherwise the selection would hardly be rigorous enough to produce any definite cumulative effect. But there does not seem to be a particle of evidence that any large number of male birds are year by year left mateless. The facts adduced by Mr. Darwin rather go the other way, for they show that any bird, male or female, always finds a new mate when its own is killed; and this is sufficiently explained by the ordinary daily mortality among birds. But if the evidence required is scanty among birds, it is altogether wanting in insects, or the facts are directly opposed to the hypothesis. Yet the sexual differences of colour among butterflies are so closely parallel to those among birds that Mr. Darwin is compelled to apply the same explanation in one case as in the other. The mass of facts accumulated by Mr. Darwin is so great, the subject is so interesting, and his explanations are supported by so many ingenious analogies, that the real difficulties seem to have been overlooked, and the great reputation of the author has led many to accept his views without much consideration.

But, although rejecting the theory propounded by Mr. Darwin, it is by no means easy to find any adequate substitute for it; yet there are several indications of the directions in which important clues will be found. We have first such cases as the colours of shells, of caterpillars, and of sea-slugs, which are admitted to be due to other causes than sexual selection. The nature of the tissues and the laws of growth are probably among the causes which have produced the elegant patterns of shells; and there seems no reason why the colours of butterflies' wings and of birds' feathers should not have been primarily due to the same causes. In shells, the action of light is in some way influential, since the lower surfaces and the parts covered by the mantle are generally less coloured—the latter point offering a striking analogy to the uncoloured state of the habitually covered portions of a butterfly's or moth's wings and those parts of a bird's plumage which are never or rarely exposed to the light. Again, although I take this opportunity of acknowledging that some portion of the views I have put forward as to the relation of sexual coloration to protection are erroneous or exaggerated, yet in other respects I am firmly convinced that the principle of protective coloration is far more effective than Mr. Darwin admits it to be, and that it acts in a variety of complex ways which have not yet been sufficiently investigated. But the most important agency of all is, I believe, a correlation of general vigour and sexual excitability with intensity of coloration and the development of dermal appendages. To these several causes, combined in various ways, and aided by sexual selection, inasmuch as strength and ardour (as manifested in the excited display of the male) is attractive to the other sex, we shall perhaps some day be able to trace much of the beauty of the animal kingdom, and the special ornaments so characteristic of the males. But, should this ever be done, our great obligations to Mr. Darwin will be, if possible, increased. For it is almost certain that, without his indomitable perseverance in collecting and arranging the evidence, his almost unexampled literary honesty in giving full prominence to every fact telling against himself, and the rigorous logic with which he has applied his theory to every available part of the animal kingdom, and thus enabled us the more readily to discover its weak points, the whole subject might have long remained in obscurity, and one of the most interesting pages of the book of nature been closed to the present generation.

The application of the theory of sexual selection to account for some of the peculiarities of the human race, has generally been felt to be one of the weakest parts of Mr. Darwin's book, and the usual arguments against it are advanced by Mr. Mivart. If, however, the main theory as applied to animals is unsound, its application to man will necessarily have to be reconsidered.

The remaining part of Mr. Mivart's book consists of replies to the criticisms of Mr. Chauncey Wright and Prof. Huxley, and of two chapters on a First Cause and on the consequences of the acceptance or rejection of the theistic philosophy as developed by our author. They contain much interesting matter, and some acute criticism on Mr. Herbert Spencer, Prof. Tyndall, and other modern writers of the same school; but the present article has already run to a sufficient length. We have endeavoured to give our readers some adequate idea of a very interesting book, and a very valuable contribution to philosophy and to biological science; but we much regret that its value and usefulness are likely to be diminished, by the prominence given to personal controversy, and by imputations against Mr. Darwin which, in our judgment, the facts adduced do not bear out.