SOCIAL TRANSITIONS 275 



book, a substratum of social tendencies that extends 

 throughout the entire animal kingdom. From this 

 substratum social life rises by the operation of dif- 

 ferent mechanisms and with various forms of expres- 

 sion until it reaches its present climax in vertebrates 

 and insects. Always it is based on phases of mass 

 physiology and social biology which taken alone seem 

 to be social by implication only. 



