432 C. M. CHILD 



This quantitative aspect of organization has been emphasized 

 here because it is essential that we distinguish clearly between 

 the specific hereditary mechanism or constitution of each particu- 

 lar protoplasm and the quantitative physiological factor which 

 makes possible the development of a definite and orderly organism 

 from this protoplasm. There has been much confusion on this 

 point, both from the preformistic and the epigenetic view-point, 

 but many different lines of evidence force us to the conclusion 

 that, while the physicochemical constitution of organs or parts 

 depends on the specific constitution of the protoplasm in which 

 they develop, the existence of organization depends primarily 

 upon graded quantitative differences in physiological condition 

 in the protoplasm. Alteration of these quantitative factors 

 determines alteration of the organization within the limits of 

 the particular protoplasm. Under this category fall all the 

 developmental modifications dependent upon differential suscep- 

 tibility. They represent, in short, alterations of the organizing 

 factor in a specific protoplasm. Such alterations according to 

 the evidence, are initiated as quantitative changes, changes in de- 

 gree, rate, intensity, rather than changes in kind, but the results, 

 both morphological and physiological, may differ in kind, that is, 

 qualitatively. 



