help being struck by his question as to the origin of such minute adaptations by means of ordinary selection. Even supposing that here and there a variation of a few spongy plates happened to arise by chance, how could these give the individual any advantage in the struggle for existence, when hundreds and thousands of them are required to make the bone better adapted for its work, so as to give to the variation a selective value? In reply I should like to ask if there is no possibility of assuming that the primary constituents (Anlagen) of a tissue occurring in many parts of the body might be improved by natural selection acting on the germ alone. Can we suppose that the feathers of birds or the hairs of mammals have originated singly by selection? In this case it is clear that intra-selection can have taken no part in their origin.
It seems to me that Roux (see Note IV, p. 57) would not have fallen into this error if he had brought forward his ingenious conception at a later period, when the question of the inheritance of acquired qualities was more fully appreciated. In the year 1881, when Roux published the views here briefly alluded to, a few scientific men had certainly expressed some doubt as to whether an inheritance of acquired characters could actually take place; but nevertheless the idea had not been followed up, nor had it been pointed out how thoroughly our conceptions as to the causes of the transmutation of species must become changed if such an inheritance should not occur. Thus we certainly cannot reproach Roux for having accepted this supposition, and for having applied it to his own theory.
