Now, by the side of these facts, the sterility of species and hybrids, let us place another; that of the fertility of varieties. So long as you breed together descendants from a common stock they continue fruitful to each other, without any check. Now, if naturalists cannot produce by selective breeding varieties from a common parentage that are infertile to each other, then it is quite clear that species did not come from varieties by the process of variation preserved by natural selection, since here is a phenomenon existing in connection with species which cannot, to all appearances, be produced by breeding together varieties. Mr. Huxley remarks on this, that if it could be proven not only that this has not been done, but that it cannot be done, then Mr. Darwin's hypothesis would be utterly shattered.[H] Well, up to the present it has not been done, the gentleman last quoted admits the fact; he asks, "what is really the state of the case? It is simply that, so far as we have gone yet with our breeding, we have not produced from a common stock two breeds, which are not more or less fertile with one another."[I] [Footnote H: Huxley's Lectures, p. 141.] [Footnote I: Lectures, p. 141.] What do these facts prove, I mean the sterility of species and hybrids on the one hand, and the fertilities of varieties, descendants from a common stock, on the other? Why that the great law of nature is, as announced in holy writ that every seed shall produce after its kind, and every fish, fowl, creeping-thing, beast, and man shall bring forth after his kind[J]--that is what it proves. And though man may for a moment by crossing species cause a slight deviation from that great law, it can be but for an instant, the monstrosity cannot be perpetuated, it dies out by being made unfruitful. [Footnote J: Gen. I: 11, 12, 21, 24, 25.] How do these facts affect the theory of evolution? Let us remember upon what that theory rests. It rests upon the principle that lower forms producing favorable variations and these being preserved by the process of natural selection amount finally to the production of distinct species; but we have seen that varieties cannot produce what may be called the great characteristic of species--infertility to each other; then also we have seen there is a check to variation in the sterility of species and hybrids. Add these facts to that other fact that neither in living nature nor in the geological records can be found the intermediate transitional forms linking together by fine gradations the species, and the theory of evolution lies stranded upon the shore of idle speculation. II.