the different aggregations of ancestral germ-plasms which are left for distribution among these innumerable germ-cells. “If one group of ancestral germ-plasms is expelled from one egg, and a different group from another egg, it follows that no two eggs can be exactly alike as regards their contained hereditary tendencies.” Granted; but this consideration applies equally to the original segregation of germ-plasms in the multiplying eggs of each ontogeny—for it follows from the theory of germ-plasm that the most primitive egg-cell in each ontogeny must have contained all the ancestral germ-plasms which are afterwards distributed among its innumerable progeny of egg-cells. And, as far as the facts of “individual variation” are concerned, I do not see why the differential partitioning of “ancestral idio-plasms” should be any better secured by nuclear division of a mature germ-cell than by that of an immature. Less so, indeed; for the wonder is that during the many-thousand-fold division of an immature ovum so precise a distribution of these “ancestral idio-plasms” is maintained, as is proved to be maintained (on the theory of germ-plasm) by the facts of heredity. However, Weismann takes a widely different view of the matter. For while he allows that “such an early reducing division would offer advantages in that nothing would be lost, for both the daughter nuclei would (? might) become eggs, instead of one of them being lost as a polar body”—while he allows this, he nevertheless rejects the possibility of “such an early reducing division.” But I do not see that the reasons which he assigns for this rejection of it are adequate. First, he says that if this were the way in which the superfluous germ-plasm of each generation were got rid of, _far too much_ provision has been made for the purpose,—seeing that the practically indefinite number of nuclear divisions which the immature germ-cells undergo would cause a much “greater decrease of the ancestral idio-plasms of each than could afterwards be compensated by the increase due to fertilization.” But this rejoinder is of cogency only if it be supposed that at each nuclear division of an immature ovum, “the ancestral idio-plasms” (germ-plasm) are incapable of the power of self-multiplication which soon afterwards becomes one of its most essential characters. Why, then, should we suppose this substance to be totally incapable of increase in the multiplying ova of ontogeny, when at the same time we are to suppose the same substance capable of any amount of increase in the multiplying ova of phylogeny? To this obvious question no answer is supplied: in fact the question is not put.