326 BRAINS OF RATS AND MEN 



an expression of the internal reserves of the organism; 

 it is one of the primary expressions of the process of 

 living. Like all other vital processes, it is one of the 

 modes of reaction of a special protoplasmic organiza- 

 tion to the environmental agencies with which it is in 

 energetic correspondence, though the connection with 

 the environmental energies is less direct than is the 

 case of that aspect of the simple reflex which is im- 

 mediate response to stimulation. Its efflorescence in 

 human behavior we call ''purpose" and 'Voluntary 

 effort." These are so important components of man's 

 action system as to justify more detailed examination. 

 The chapter which follows is taken (with slight modi- 

 fication), by kind permission of the editor, from an 

 article in the Psychological Review (1925^) entitled, 

 "The Natural History of Purpose." 



