84 ANALYSIS OF THU POUR PRINCIPLES. 



the other sex, in order that the individual may secure success and 

 influence in the community. 



WiUiam E. D. Scott, curator of ornithology of Princeton University, 

 tells of a red-winged blackbird which, for the sake of testing the power 

 of tradition, was, from the day he left the egg, " brought up by hand, in 

 a room by himself, away from all sounds, as was supposed. The result 

 was that when the time came for him to sing he crowed like a rooster. 

 It then developed that every morning a bantam rooster had crowed 

 under his window."* Whether he was able to win any mate among 

 his fellow captives is not mentioned ; but if he had been turned loose 

 to seek a mate among his kindred of the wild, his inability to use the 

 song of his kind would certainly have given great advantage to his 

 rivals who had learned the true song of the species. 



Sexual isolation arises between groups of the same species that have 

 been separated by geographical barriers for several generations, and 

 have in the meantime attained divergent forms of inherited characters 

 by which they recognize each other, and different methods of calling 

 each other and winning each other. Though physiologically any 

 cross between the two races is both fertile and vigorous, psychologi- 

 cally they are prevented from crossing through incompatibility in 

 sexual instincts and inherited endowments. 



I judge that there is no need of distinguishing sexual partition from 

 sexual isolation, for an associating group determined by sexual habits 

 and instincts would surely be an intergenerating group. 



3. The Social Form of Selection, Election, Isolation, and Partition. 



Social selection is due to the necessity for coordination between the 

 social instincts and endowments of the individual and the social 

 instincts and endowments of the race, in order that the individual 

 should secure a chance to survive and propagate. We find that under 

 the same environment there are many possible instinctive calls, and 

 many arrangements of color, and many combinations of inherited 

 odors, by which the individuals of one race recognize each other. By 

 means of characters that we are unable to note the bees of one hive 

 recognize each other, and there is reason to believe that serious 

 deficiency in any essential character would lead to the exclusion of 

 the deficient individual from the privileges of the community. The 

 power to recognize one's own race by scent is not as wonderful as the 

 power of the bloodhound to distinguish between individuals in the 

 same way. Not only must the distinctive character of the race be 



* See The Outlook (of New York) for July 5, 1902. 



