i6 



THE ORIGIN AND EVOLUTION OF LIFE 



special part. Through such interaction the organism is made 

 a unit and acts as one, because the activities of all its parts 

 are correlated. This idea may be expressed in the follov\dng 

 simplified scheme of the functions or physiology of the organism; 



ACTION ] 



AND \ 



REACTION J 



Functions of the 



Capture, Storage, 



and Release of 



Energy. 



INTERACTION 



Functions of the 



Coordination, Balance, 



Cooperation, Compensation, 



Acceleration, Retardation, 



of Actions and Reactions. 



ACTION 

 AND 

 [ REACTION 



Functions of the 



Capture, Storage, 



and Release of 



Energy. 



Since it is known that many actions and reactions of the 

 organism — such as those of general and localized growth, of 

 nutrition, of respiration — are coordinated with other actions 

 and reactions through interaction, it is but a step to extend 

 the principle and suppose that all actions and reactions are sim- 

 ilarly coordinated; and that while there was an evolution of 

 action and reaction there was also a corresponding evolution 

 of interaction, for without this the organism would not evolve 

 harmoniously. 



Evidence for such universality of the interaction principle 

 has been accumulating rapidly of late, especially in experi- 

 mental medicine^ and in experimental biology.- It is a further 

 step in our theory to suppose that the directing power of he' 

 redlty which regulates the initial and all the subsequent steps 

 of development in action and reaction, gives the orders, hastens 

 development at one point, retards it at another, is an elab- 

 oration of the principle of interaction. In lowly organisms 



* See the works of Gushing and Crile cited below. 

 - See the recent experiments of Morgan and Goodale. 



