298 EVOLUTION, GENETICS, AND EUGENICS 



are at best modifying factors. Of course, there is no denying the fact 

 that in a sense environment and training are just as essential as he- 

 redity for development of any sort, since without a reasonably suitable 

 environment and an opportunity of functioning, an individual could not 

 live at all. But it must be admitted that it is heredity that determines 

 whether a germ cell shall develop into a man or a pig, a white man or 

 a Negro, an intelligent man or a dullard. Environment cannot change 

 one into the other, but it may make the one a better man, the other 

 a better pig; or training may make an intelligent man more intelligent 

 or a dullard a somewhat more presentable dullard. A large part of the 

 subject of genetics is devoted to the study of heredity more or less to 

 the exclusion of that of environment and of training. No apology is 

 needed for this type of specialization, for the geneticist is convinced 

 that it is in a study of heredity and allied phenomena that the great 

 problem of organic evolution lies. Doubtless in the -course of time, 

 when heredity is adequately understood, the working evolutionist may 

 shift his interest and devote his attention to the factors of environment 

 and training. 



