36 TABOO AND GENETICS 



Mendel's experiments had shown that the 

 characters we inherit are units or combinations 

 of units, very difficult to permanently change 

 or modify. They combine with each other in all 

 sorts of complicated ways. Sometimes one will 

 " dominate " another, causing it to disappear 

 for a generation or more ; but it is not broken 

 up. These characters have a remarkable way 

 of becoming " segregated " once more — that is, 

 of appearing intact later on. 



While it follows from Weismann's theory 

 that an adaptation acquired by an individual 

 during his lifetime cannot be transmitted to his 

 offspring, it remained for De Vries to show 

 authoritatively that evolution can, and does, 

 take place without this. Once this was estab- 

 lished, biologists cheerfully abandoned the earUer 

 notion. Lester Ward and the biologists of his 

 day in general not only believed in the trans- 

 mission of acquired characters, but they filled 

 the obvious gaps which occurred in trying to 

 apply this theory to the observed facts by 

 placing a fantastic emphasis upon sexual selec- 

 tion. That is, much progress was accounted 

 for through the selection by the females of 

 the superior males. This, as a prime factor in 

 evolution, has since been almost " wholly dis- 

 credited " (Kellogg's phrase) by the careful 

 experiments of Mayer, Soule, Douglass, Diirigen, 

 Morgan and others. The beUef in sexual 



