Method of Regulation in Behavior and in Other Fields. 479 



best thing to do is to change this behavior. If the unfavorable 

 condition still continues the behavior is changed again; this being 

 continued, the organism is bound to escape from the interfering 

 condition if it is possible to do so. In some cases the move- 

 ments produced are, when considered by themselves, of a rather 

 uniform character, yet are of such a nature as to subject the animal 

 to many changes of the environmental conditions. This is the 

 case for example in the reactions of such infusoria as Paramoecium, 

 where the character of the movement is determined partly by 

 structure, yet involves a continued change of relation to the outer 

 conditions. In other cases the movements themselves are varied 

 in character, the organism first reacts in one way, then in another, 

 running through a whole series of activities, till one results in 

 ridding the organism of the stimulating condition. This is the 

 method of behavior seen in Stentor and in most higher organisms. 



Our third question was: How does the organism select the 

 more favorable condition thus reached .? This question now 

 answers itself. It was interference with the physiological pro- 

 cesses that caused the changes in behavior. As soon, therefore, 

 as this interference ceases, there is no further cause for change. 

 The organism selects and retains the favorable condition reached 

 merely by ceasing to change its behavior when interference ceases. 

 This process is seen clearly in the behavior of such infusoria as 

 Paramoecium. 



It is perhaps fairly evident how reaction on the plan just 

 described may result in the avoidance or rejection of sources of 

 interfering stimuli; in other words, in the production of negative 

 reactions. The matter of positive reactions should perhaps receive 

 further elucidation. 



In conditions that are completely favorable — so that all the life 

 processes are taking place without lack or hindrance — there is no 

 need, from the standpoint of regulation, for a change in behavior — 

 for definite reactions of any sort The most natural behavior on 

 reaching such conditions, and that which is actually found as a 

 rule among lower organisms, is a continuation of the activities 

 already in progress. These activities have resulted in the favor- 

 able conditions, and there is no cause for a change. This we 

 find exemplified in infusoria, bacteria, rotifers, and many other 

 organisms, under most classes of conditions. A change in 

 behavior takes place only when the activities tend to remove the 



