PHYSIOLOGICAL STATES AS DETERMINING FACTORS. 127 



of stimuli," "heterogeneous induction," "spontaneous movements," 

 and "changes in the sense of reactions with a change of intensity in 

 the stimulus," are developed. 



The view is set forth that in most of the lower organisms a reaction 

 to stimulus usually involves the following factors: (i) the stimulus 

 changes the physiological state of the organism as a whole ; (2) this 

 change in physiological state induces a certain type of reaction. 

 Evidence for this view is summarized. 



Finally, it is pointed out that realization of the importance of 

 physiological states as determining factors in the behavior of the lower 

 organism is of service in bringing the study of these organisms into 

 relation with that of higher animals and man. An objective study of 

 the behavior of these higher animals shows the prevalence of physio- 

 logical states as determining factors in behavior, and in some cases, at 

 least, some of these states are closely analogous to what we find even 

 in unicellular organisms. 



