THEORY OF EVOLUTION 



IT 



world. Ilundreds of such enilMyonic a(la])ta- 

 tions are known to enibryolooists. Tliese were 

 explained as adaptations and as falsifications 

 of tlie ancestral records. 



At tlie end of the last century Weisniann in- 



P'lc;. 7. Diagram of chic]-; sliitwing rflatioiis of aimiio;i, 

 allantoic and yolk. (After I.iUie.) 



jected a new idea into our views concerning- 

 tlie ori<)in of variations. He urged that varia- 

 tions are germinal, i.e. they first appear in the 

 f^gg and the sperm as cJianges that later bring 

 about modifications in tlie individual. The 

 idea lias been fruitful and is generally accepted 

 l)y most biologists today. It means tliat tlie 



