Chapteh XII 



THE NON-INHERITANCE OF 

 ACQUIRED CHARACTERS^ 



For more than a hundred years the question has 

 been discussed as to whether habits and physical 

 characteristics acquired by an individual during its 

 life are transmitted to its children. Lamarck's theory 

 of evolution rests on the assumption that adapta- 

 tions in the animal kingdom are brought about in 

 this way. Although Darwin once referred contemp- 

 tuously to Lamarck's nonsense, which he understood 

 to imply that adaptation results from the slow will- 

 ing of animals, he later accepted a view that is in all 

 essential respects really the same as Lamarck's. In 

 fact, Darwin went even further than Lamarck in 

 attempting to explain by means of his hypothesis of 

 pangenesis how changes in the body might be trans- 

 mitted to the reproductive cells and reap2:)ear in the 

 offspring. 



Despite the high authority of Darwin's name 

 there has been a steady falling away from this belief 

 amonff biologists trained in modern methods of ex- 

 perimental research. It is true that among stock 

 breeders and farmers there has always been, and 

 there is still, a widespread conviction that acquired 



1 From The Yale Revieio, July 19:24. 



