ANALYSIS OF BEHAVIOR IN LOWER ORGANISMS 289 



(10) Physiological Slates change in Accordance with Certain Laws. — 

 It is evident that we may distinguish at least two great classes of physio- 

 logical states, — those depending on the progress of the metabolic 

 processes of the organism, and those otherwise determined. The changes 

 in the metabolic states, as we may call the former, of course depend largely 

 upon the laws of metabolism. In the physiological states not directly 

 dependent on metabolism, but rather upon stimulation and upon the 

 activity of the organism, such as we have seen in Stentor, we find certain 

 fairly well-defined laws of change, of a peculiar character. 



In a number of organisms we have found the following phenomenon : 

 Under certain conditions the organism reacts in a certain way. These 

 conditions continuing, the organism changes its first reaction for a second 

 or third or fourth. Later the same external conditions recur, and now 

 the organism at once responds, not by its first reaction, but by its final 

 one. This is illustrated for unicellular organisms by the case of Stentor 

 (Chapter X); for higher Metazoa it is well seen in the behavior of cer- 

 tain Crustacea, as described by Yerkes and Spaulding (Chapter XII). 

 There are certain differences in these two cases that will be taken up 

 later. 



How does this state of affairs come about? The "physiological 

 state " is evidently to be looked upon as a dynamic condition, not as 

 a static one. It is a certain way in which bodily processes are taking 

 place, and tends directly to the production of some change. In this 

 respect the "law of dynamogenesis," propounded for ideas of movement 

 in man, applies to it directly (see Baldwin, 1897, p. 167); ideas must 

 indeed be considered, so far as their objective accompaniments are con- 

 cerned, as certain physiological states in higher organisms. The changes 

 toward which the physiological state tends are of two kinds. First the 

 physiological state (like the idea) tends to produce movement. This 

 movement often results in such a change of conditions as destroys the 

 physiological state under consideration. But in case it does not, then 

 the second tendency of the physiological state shows itself. It tends to 

 resolve itself into another and different state. Condition 1 passes to 

 condition 2, and this again to condition 3. This tendency shows itself 

 even when the externaL conditions remain uniform. 



In this second tendency a most important law manifests itself. When 

 a certain physiological state has been resolved, through the continued 

 action of an external agent or otherwise, into a second physiological 

 state, this resolution becomes easier, so that in the course of time it 

 takes place quickly and spontaneously. 



This may be illustrated from the behavior of Stentor, as described 

 in Chapter X as follows : When the organism is stimulated by the flood 



