136 An Examination of Weismanmsm. 



carriers of heredity composing the stirp of a fertilized 

 ovum. It is not. however, a struggle for existence, 

 but what may be called a struggle for development. 

 In the fertilized ovum all the carriers of heredity are. 

 to begin with, in a " latent " condition ; but of this 

 enormous multitude of *'• germs '"' or " gemmules," only 

 a very small proportional number are destined to 

 become " patent " — i. e.. developed into the tissue-cells 

 composing the new organism. The vast majority 

 of the gemmules, or those which fail to be thus de- 

 veloped, go to constitute the stirp of the new organism 

 when this has been formed by the development of the 

 comparatively few successful gemmules. Thus much 

 understood, the following quotation will be fully 

 intelligible. 



My argument is this : Of the two groups of germs, the 

 one consisting of those that succeed in becoming developed 

 and in forming the bodily structure, and the other consisting of 

 those that remain continually latent, the latent vastly prepon- 

 derates in number. We should expect the latent germs to 

 exercise a corresponding predominance in matters of heredity. 

 unless it can be shown that, on the whole, the germ that is 

 developed into a cell becomes thereby more fertile than if it had 

 remained latent. But the evidence points the other way. It 

 appears both that the period of fertility is shorter, and the 

 fecundity even during that period is less in the germ that 

 becomes developed into a cell, than they are in the germ that 

 remains latent. Much less then would the entire bodily 

 structure, which consists of a relatively small number of these 

 comparatively sterile units, successfully compete in matters of 

 heredity with the total effect of the much more numerous and 

 more prolific units which are in a latent form 1 . 



Thus, Galton's theory of the mechanism of onto- 



1 Loc. cit., p. 339. 



