68 Heredity and Instinct 



use the same coordinations intelligently or imitatively, 

 prevent natural selection getting into operation, and so 

 instinctive 'thumb-grasping* might be waited for indefi- 

 nitely by the species and tJien arise by accumulated vari- 

 ation, altogether apart from use-inheritance. 



We may say, therefore, that there are two great kinds 

 of influence, each in a sense hereditary: there is pJiysical 

 heredity by which variations are congenitally transmitted 

 with original endowment, and there is ' social heredity ' by 

 which functions socially acquired (i.e., imitatively, covering 

 all the conscious acquisitions made through intercourse 

 with other animals) are socially transmitted. The one 

 is phylogenetic ; the other, ontogenetic. But these two 

 lines of transmission are not separate nor are they un- 

 influential on each other. Congenital variations, on the 

 one hand, are kept alive and made effective by their con- 

 scious use for intelligent and imitative accommodations in 

 the life of the individual ; and, on the other hand, intelligent 

 and imitative accommodations become congenital by further 

 progress and refinement of variation in the same lines of 

 function as those which their acquisition by the individual 

 called into play. But there is no need in either case to 

 assume the Lamarckian factor. 



The intelligence holds a remarkable place in each of 

 these categories. It is itself, as we have seen, a con- 

 genital variation ; but it is also the great agent of the 

 individual's personal accommodations both to the physical 

 and to the social environment. 



The emphasis, however, of the first of these two lines 

 of transmission gives prominence to instinct in animal 

 species, and that of the other to the intelligent and social 

 cooperation which goes on to be human. The former 



