INFLUENCE OF ENVIRONMENT 355 



A striking instance of the purely temporary 

 effect of the environment and of the long per- 

 sistence of hereditary constitution amidst new 

 environmental conditions, which have greatly 

 changed the appearance of the developed or- 

 ganism, is found in the case of alpine plants. 

 Nageli says that such plants, which have pre- 

 served the characters of high mountain plants 

 since the ice age, lose these characters perfectly 

 during their first summer in the lowlands. 



If acquired characters were really inherited 

 we should expect to find many positive evi- 

 dences of this instead of a few sporadic and 

 doubtful cases. In particular why do we not 

 find in plant or animal grafting that the in- 

 fluence of the stock changes the hereditary po- 

 tencies of the graft? Why do we not find 

 that transplanted ovaries show the influence of 

 the foster mother as Guthrie supposed — a 

 thing which has been disproved by Castle 

 (Figs. 81 and 82) ? Why do dominant and 

 recessive characters remain pure, even after 



All the offspring are pure black, though both parents are 

 pure white, because the white female contains only "black" 

 eggs and black is dominant over white. (From Castle.) 



