84 : ANALYSIS OF THE FOUR PRINCIPLES. 
the other sex, in order that the individual may secure success and 
influence in the community. 
William 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 tsolation 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 codrdination 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. 
