Now what can be more simply reconcilable with that theory than Mr. Darwin's own account of the mode in which the migration of animal life from one distant region to another is continually accomplished?
Take another of these suggestions:—
It is inexplicable, on the theory of creation, why a part developed in a very unusual manner in any one species of a genus, and therefore, as we may naturally infer, of great importance to the species, should be eminently liable to variation.—p. 474.
Why "inexplicable"? Such a liability to variation might most naturally be expected in the part "unusually developed," because such unusual development is of the nature of a monstrosity, and monsters are always tending to relapse into likeness to the normal type. Yet this argument is one on which he mainly relies to establish his theory, for he sums all up in this triumphant inference:—
I cannot believe that a false theory would explain, as it seems to me that the theory of natural selection does explain, the several large classes of facts above specified.—p. 480.
Now, as to all this, we deny, first, that many of these difficulties are "inexplicable on any other supposition." Of the greatest of them (128, 194) we shall have to speak before we conclude. We will here touch only on one of those which are continually reappearing in Mr. Darwin's pages, in order to illustrate his mode of dealing with them. He finds, then, one of these "inexplicable difficulties" in the fact, that the young of the blackbird, instead of resembling the adult in the colour of its plumage, is like the young of many other birds spotted, and triumphantly declaring that—
No one will suppose that the stripes on the whelp of a lion, or the spots on the young blackbird, are of any use to these animals, or are related to the conditions to which they are exposed.—pp. 439-40—
he draws from them one of his strongest arguments for this alleged community of descent. Yet what is more certain to every observant field-naturalist than that this alleged uselessness of colouring is one of the greatest protections to the young bird, imperfect in its flight, perching on every spray, sitting unwarily on every bush through which the rays of sunshine dapple every bough to the colour of its own plumage, and so give it a facility of escape which it would utterly want if it bore the marked and prominent colours, the beauty of which the adult bird needs to recommend him to his mate, and can safely bear with his increased habits of vigilance and power of wing?
But, secondly, as to many of these difficulties, the alleged solving of which is one great proof of the truth of Mr. Darwin's theory, we are compelled to join issue with him on another ground, and deny that he gives us any solution at all. Thus, for instance, Mr. Darwin builds a most ingenious argument on the tendency of the young of the horse, ass, zebra, and quagga, to bear on their shoulders and on their legs certain barred stripes. Up these bars (bars sinister, as we think, as to any true descent of existing animals from their fancied prototype) he mounts through his "thousands and thousands of generations," to the existence of his "common parent, otherwise perhaps very differently constructed, but striped like a zebra."—(p. 67.) "How inexplicable," he exclaims, "on the theory of creation, is the occasional appearance of stripes on the shoulder and legs of several species of the horse genus and in their hybrids!"—(p. 473.) He tells us that to suppose that each species was created with a tendency "like this, is to make the works of God a mere mockery and deception"; and he satisfies himself that all difficulty is gone when he refers the stripes to his hypothetical thousands on thousands of years removed progenitor. But how is his difficulty really affected? for why is the striping of one species a less real difficulty than the striping of many?
Another instance of this mode of dealing with his subject, to which we must call the attention of our readers, because it too often recurs, is contained in the following question:—