The American palæontologist, Osborn, cites the case of the horse's feet as an example in support of his view that modification brought about by use in the individual life must be transmitted in order that the phyletic transformations may be brought about, but this example is perhaps the best that could be chosen to prove the contrary. He supposes that, in every young horse, the means of locomotion are improved at every step, so to speak, through the contact with the ground, and I am quite willing to admit that this is so. But that only proves that, even now, an elaboration and improvement of the equipment which the germ affords is indispensable, as it has been at all times and in all animals, and thus that, notwithstanding the enormous number of generations which our modern horse has behind it, the functional acquirements of the individual have not yet been impressed upon the germ. Why not? Because the horse becomes perfect without this, and there was no reason why personal selection should perfect the primary constituents of the germ still further, since the finishing touch of perfection through use is readily afforded by the conditions of each individual life. Moreover, when Osborn, Cope, and other palæontologists emphasize that, in phyletic evolutionary series, _definite paths of evolutionary_ change are adhered to, and are not deviated from either to right or to left, they are undoubtedly right, but the conclusion which they draw is not justifiable, whether they assume with Nägeli that there is a power of development, a principle of perfecting, or whether, as Osborn does, they assume the transmission of the modifications brought about through use in the individual life. There remains a third possibility, that the quiet and constant evolution in a definite direction is guided by selection, and as, in passively useful parts, that principle alone is admissible, I see no justification for assuming it to be inoperative in regard to those which are actively functional. All these variations which have led up, for instance, to the modern form of the horse's foot are useful; if they were not, they could not have been produced either by use or by disuse in the individual life. At the same time, here again, we are justified in inquiring whether the assumption of 'chance' germinal variations, which we have hitherto made with Darwin and Wallace, affords a sufficient basis for selection. Osborn says very neatly in this connexion, 'We see with Weismann and Galton the element of chance; but the dice appear to be loaded, and in the long run turn "sixes" up. Here arises the question: What loads the dice?'