114 Heredity. 



A little thought will show that if there were no expla- 

 nation of the transmission of latent sexual characteristics 

 more simple than the hypothesis of a dual personality, 

 this hypothesis would then be too simple, and would 

 need to be made much more complicated. 



The characteristics of the opposite sex are not the only 

 ones which may be latent, and in cases of reversion a 

 parent may transmit to children characteristics which 

 were exhibited by neither parent nor grandparent, and 

 which may have remained latent for many generations. 



If we must assume the existence of a dual personality 

 to account for the latent transmission of the character- 

 istics of the grandparent of the opposite sex, we must 

 assume still other personalities to account for reversion 

 to more remote ancestors, and Darwin has not hesitated 

 to carry the hypothesis to this, its logical conclusion. 



He says (Variation, ii. 65), "Several authors have 

 maintained that hybrids and mongrels include all the 

 characteristics of both parents, not fused together but 

 merely mingled in different proportions in different 

 parts of the body; or, as Naudin has expressed it, a hy- 

 brid is a living mosaic work, in which the eye cannot 

 distinguish the discordant elements, so completely are 

 they intermingled. We can hardly doubt that, in a 

 certain sense, this is true, as when we behold in a hybrid 

 the elements of both species segregating themselves into 

 segment in the same flower or fruit by a process of self- 

 attraction or self-affinity this segregation taking place 

 either by seminal or by bud propagation. Naudin fur- 

 ther believes that the segregation of two specific elements 

 or essences is eminently liable to occur in the male and 

 female reproductive matter, and he thus explains the 

 almost universal tendency to reversion in successive 

 hybrid generations. . . . But it would, I suspect, 



