264 



Heredity and Environment 



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FIG. 93. WILD BOAR CONTRASTED WITH MODERN DOMESTIC PIG. (From 

 Romanes.) 



I. THE INFLUENCE OF ENVIRONMENT IN PRODUCING 

 NEW RACES 



There is a popular belief that the improvement of cultivated 

 races is due to good environment, good food, good soil, protection 

 from enemies, etc., and that if turned out to shift for themselves 

 such races revert at once to the original wild stock. This is not 

 strictly true but if it were there are two ways in which it is con- 

 ceivable that new races might be produced by environmental 

 influences : 



i. By the direct inheritance of somatic or personal characters 

 acquired under the stimulus of the environment. In spite of popu- 

 lar opinion in favor of this view there is no evidence that this 

 ever occurs. There is no doubt that environment has much to 

 do with individual development, but it does not usually modify 

 the hereditary constitution of the race. 



