202 INDIVIDUALITY IN ORGANISMS 



HEREDITY, EVOLUTION, AND OTHER PROBLEMS FROM THE 

 DYNAMIC STANDPOINT 



If the organism is fundamentally a specific reaction 

 system in which quantitative differences initiate physio- 

 logical individuation, development, and differentiation, 

 nothing can be more certain than that it acts essentially 

 as a unit in inheritance. It is the fundamental reaction 

 system which is inherited, not a multitude of distinct, 

 qualitatively different substances or other entities with 

 a definite spatial localization. Development is not a 

 distribution of the different qualities to different regions, 

 but simply the realization of possibilities, of capacities 

 of the reaction system. The process of realization differs 

 in different regions because the conditions are differ- 

 ent. Neither characters nor factors as distinct entities 

 are inherited, but rather possibilities, which are given 

 in the physico-chemical constitution of the fundamental 

 reaction system, but not necessarily localized in this 

 or that part of it. 



The fact that in the past investigation of inheritance 

 has been almost entirely limited to the special aspects 

 of heredity and development connected with gametic 

 reproduction has contributed very largely to delay our 

 progress and limit and distort our conceptions of the 

 processes of inheritance. This, the most highly special- 

 ized form of reproduction, is the most unfavorable 

 point of attack upon the problems involved, for the 

 possibilities of control of the earlier stages of individu- 

 ation are narrowly limited, and many factors which 

 are not really essential to reproduction and develop- 

 ment are characteristically present in this reproductive 

 process. 



