i8o PIONEERS OF EVOLUTION PART 



ences in the circumstances of the different parts of 

 the aggregate. 



5. These secondary changes constitute a trans- 

 formation of the homogeneous into the hetero- 

 geneous a transformation which, like the first, is 

 exhibited in the universe as a whole and in all 

 (or nearly all) its details ; in the aggregate of stars 

 and nebulae ; in the planetary system ; in the earth 

 as an inorganic mass ; in each organism, vegetal 

 or animal (von Baer's law otherwise expressed) ; 

 in the aggregate of organisms throughout geologic 

 time; in the mind; in society; in all products of 

 social activity. 



6. The process of integration, acting locally as 

 well as generally, combines with the process of 

 differentiation to render this change not simply 

 from homogeneity to heterogeneity, but from an 

 indefinite homogeneity to a definite heterogeneity ; 

 and this trait of increasing definiteness, which 

 accompanies the trait of increasing heterogeneity, 

 is, like it, exhibited in the totality of things 

 and in all its divisions and subdivisions down to 

 the minutest. 



7. Along with this redistribution of the matter 

 composing any evolving aggregate there goes on 

 a redistribution of the retained motion of its 

 components in relation to one another ; this also 

 becomes, step by step, more definitely hetero- 

 geneous. 



8. In the absence of a homogeneity that is 

 infinite and absolute, that redistribution, of which 

 evolution is one phase, is inevitable. The causes 

 which necessitate it are these : 



