20 A NEW THEORY OF EVOLUTION. 



the race selected, fertility may be main- 

 tained, and individuals apparently pure will 

 ultimately be produced ; but even after 

 several generations a calf will occasionally 

 appear with distinct characteristics of the 

 discarded breed. 



Such cases of atavism seem to indicate 

 a reluctance in Nature to lose a type, and 

 also a tendency in the event of an acci- 

 dental deviation a monstrosity, for ex- 

 ample to revert to the original form. 



Crossing between two races occurs but 

 rarely in a state of nature. The brown 

 and the mountain hare, although similar, 

 do not mate, even when they live together 

 on the same mountain - side ; neither do 

 grouse and ptarmigan ; and it may be 

 doubtful whether cattle of different breeds 

 would mate together if free to choose. 



We certainly know that a strong feel- 

 ing of aversion exists between many races 

 of mankind 1 probably more or less among 

 all. 



It is remarkable that of white races this 

 aversion is strongest in Gipsies and Jews, 

 who, living amongst other nations, might be 

 expected to have the strongest temptations 

 to intermarry with another race. 



1 Witness the lynchings in the United States. 



