32 THEORY OF EVOLUTION 



Practice makes perfect is a familiar adage. 

 JVot only in human affairs do we find that a 

 part through use becomes a better tool for 

 performing its task, and through disuse de- 

 generates; but in the field of animal behavior 

 we find that manj^ of the most essential types 

 of behavior have been learned through repeated 

 associations formed by contact with the outside. 



It was not so long ago that we were taught 

 that the instincts of animals are the inherited 

 experience of their ancestors — lapsed intelli- 

 gence was the current phrase. 



Lamarck's name is always associated with 

 the application of the theory of the inheritance 

 of acquired characters. Darwin fully en- 

 dorsed this view and made use of it as an expla- 

 nation in all of his writings about animals. 

 Today the theory has few followers amongst 

 trained investigators, but it still has a popular 

 vogue that is widespread and vociferous. 



To Weismann more than to any other single 

 individual should be ascribed the disfavor into 

 Ti^hich this view has fallen. In a series of bril- 

 liant essays he laid bare the inadequacy of the 

 supposed evidence on which the inheritance of 



