EVOLUTION AND HEREDITY. I3I 



Yet men were slow to see this relation. Lamarck 

 did not study heredity as a special problem in itself, but 

 he boldly postulated the only theory which fitted his 

 views of evolution. Darwin really gave it a compara- 

 tively small share of his thought, and only after he had 

 modified his views of the omnipotency of natural selec- 

 tion,^ did he begin to feel the absolute necessity for a 

 working hypothesis of inheritance. But now the hered- 

 ity problem is no longer the subsidiary one, in fact, 

 just at the present time, it is the chief one, for the whole 

 accepted theory of the process of evolution has been 

 overthrown by a brilliant student of heredity ; and there 

 are two parties, each attempting to throw the onus pro- 

 bandi upon the shoulders of the other. It is clear 

 enough that when we have reached an heredity theory 

 which will explain the phenomena of inheritance, the 

 method of evolution will itself be a problem of the past. 

 No such explanation can be reached, however, so long 

 as students of heredity take only a partial view of the 

 facts of evolution. The present temper of Weismann 

 and his English followers is apparently somewhat exclu- 

 sive ; the same is equally true of some of our friends on 

 this side of the Atlantic. 



What then is necessary in a complete theory of hered- 

 ity.'* It must account for the repetition phenomena; 

 these were the first to attract attention, for we are 

 always more struck by the features in which the off- 

 spring resembles the parents than by those in which it 

 differs. Under this head are included " reversions." 



1 This change of view becomes most evident in his Animals and 

 Plants under Domestication, in the closing part of which Pangenesis is 

 proposed. 



