72 HEREDITY AND ENVIRONMENT 



named; the germ cells and embryo represent 

 only the stages of reflex behavior, to these trial 

 and error and associative memory are added in 

 the infant and young child, and to these the 

 application of past experience to new condi- 

 tions, or reason, is added in later years. 



5. Will. — Another characteristic, which 

 many persons regard as the supreme psychical 

 faculty, is the will. This faculty also under- 

 goes development and from relatively simple 

 beginnings. The will of the child has devel- 

 oped out of something which is far less perfect 

 in the infant and embryo than in the child. 

 Observations and experiments on lower ani- 

 mals and on human beings, as well as intro- 

 spective study of our own activities, appear to 

 justify the following conclusions: 



(1.) Every activity of an organism is a 

 response to one or more stimuli, external or 

 internal in origin. These stimuli are in the 

 main, if not entirely, energy changes outside 

 or inside the organism. In lower organisms 

 as well as in the germ cells and embryos of 

 higher animals the possible number of re- 

 sponses are few and prescribed owing to their 



