Whether the views put forward by Mr. Wallace do in reality render unnecessary the Darwinian hypothesis of sexual selection will not be here discussed; it is sufficient to note that the conclusions of Mr. Darwin in this not unimportant matter have, after abundant time for examination and reflection, been rejected by the naturalist who more perhaps than any other has a right to criticise him.
But Mr. Wallace rejects also the evolutionist views of another very competent naturalist, Prof. Romanes; and it will aid in the development of the purpose of this paper if I refer in passing to this rejection. The theory of Prof. Romanes is described by him under the phrase "it is not necessary in this place to explain what the theory is; it is sufficient to say it is regarded as highly important by Prof. Romanes, and as utterly unfounded by Mr. Wallace. It would be impertinent on my part to offer any opinion as between these two authorities; but the conclusion may be fairly drawn that there is probably much at present unknown in the subject of evolution, as well as not a little doubt with regard to some fields of inquiry into which our knowledge is supposed to extend.
But the most striking and interesting feature of Mr. Wallace's book, from what I may describe as the human point of view, is to be found in that part of his work in which he denies, and (as he believes) proves himself to be justified in denying, the application of the principle of natural selection to the evolution of the human faculties. This denial is a fact of the first order of magnitude; and I confess that I can see no ground for the language of strong depreciation in which Prof. Romanes, in the article already referred to, describes this portion of Mr. Wallace's book. He speaks of the substance of the concluding chapters as being "sadly like the feet of clay in a figure of iron, marring by its manifest weakness what would otherwise have been a completed and self-consistent monument of strength." No argument in the article justifies this condemnation; and it is, perhaps, not too much to say that many of his readers will find in the condemned portion of Mr. Wallace's book that which has the deepest interest for themselves, while it must not be forgotten that the views put forward are alleged by Mr. Wallace to rest upon proofs which he formally submits for examination. Let us see, then, what this clay formation contains.
Mr. Wallace fully accepts "Mr. Darwin's conclusion as to the essential identity of man's bodily structure with that of the higher mammalia, and his descent from some ancestral form common to