DEVELOPMENT OF BEHAVIOR 317 



reactions. Other advances would come in the production of different 

 physiological states according to the different organs or parts of the body 

 stimulated; this condition would naturally arise as structural differen- 

 tiations were developed in the body. As new organs develop and the 

 body becomes more complex, each part will naturally have physiological 

 states peculiar to itself, and will be acted upon by external stimuli, 

 producing changes in its physiological states. This is evidently the case 

 in such organisms as the sea urchin and sea anemone. These partial 

 physiological states of the different organs will then interact, altering 

 each other and combining to form a general state for the entire organism. 

 All the partial physiological states will be regulated, as in the separate 

 organism, bv their relation to the normal life current of the organ con- 

 cerned, and further, their combinations will be regulated by their rela- 

 tion to the general life current of the organism. Whatever interferes 

 with this normal life current will be changed, while that which does 

 not interfere must persist. The partial and general physiological 

 states will be subject to the laws of the combination and regulation of 

 physiological states, just as in simple organisms. They will tend to 

 discharge themselves in action, or by resolution into other states, as in 

 the simple organisms. Thus the behavior of the organism must become 

 in time controlled by these physiological states, derived from many 

 sources besides that of the present stimulus. Behavior is gradually 

 emancipated from its bondage to present external conditions, and de- 

 pends largely upon the past experience and present needs of the organism. 

 This is the condition we find in higher animals, and especially in man. 



The various stages set forth above are merely logical divisions, and 

 probably do not correspond in any close way to actual stages in the de- 

 velopment of behavior. There seems to be no reason to suppose that 

 an organism ever existed in which the original state is immediately 

 restored on the cessation of a stimulus. This immediate return to the 

 original state is not what we should expect from analogy even with inor- 

 ganic substances. 1 Even in unicellular organisms we find a consider- 

 able complication of physiological states, depending on past stimuli, 

 past reactions, localization of the stimulus, and present external condi- 

 tions, as well doubtless as upon other factors. 



Progress along the line just set forth will be brought about by the 

 same factors, whatever they may be, that determine the development 



1 With relation to colloids, the substances of which organisms are mainly composed, 

 a high authority in physical chemistry remarks as follows: "Their qualities often 

 depend in the clearest way upon the former history of the colloid, its age, its previous 

 temperature, and the time this continued : in short, on the way it has reached its present 

 condition " (Bredig, 1902, p. 183). The facts of behavior in organisms might be cited 

 as illustrations of this statement. 



