REGULATION IN BEHAVIOR 347 



lation, respiration becomes for a time rapid, then is almost suspended. 

 The heart beats for a time furiously, then feebly, and there is similar 

 variation in other internal symptoms. 



Thus it seems clear that interference with the life processes does 

 produce varied activities in other ways than in bodily movements ; and 

 that among these it results in varied chemical processes. There is then 

 presented opportunity for regulation to occur in the same way as in 

 behavior. Certain of the processes occurring relieve the disturbance of 

 the physiological functions. There results a cessation of the changes. 

 In other words, a certain process is selected through the fact that it does 

 relieve. It is well known, through the work of Pawlow (1898), that the 

 adaptive changes in the activities of the digestive glands, fitting the 

 digestive juices to the food taken, do not occur at once and completely 

 under a given diet, but are brought about gradually. As the dog is 

 continued on a diet of bread, the pancreatic juice becomes more and 

 more adapted to the digestion of starch. This slow adaptation is of 

 course what should be expected if the process occurs in anything like 

 the manner we have sketched. 



At a later stage, if the laws of these processes are the same as those 

 for behavior, there will be present certain fixed methods of chemical 

 response, by which the organism reacts to certain sorts of stimulation. 

 That the law of the readier resolution of physiological states after repe- 

 tition holds in this field, is clearly indicated by the work of Pawlow. He 

 found that the pancreas under a uniform diet does tend to acquire a 

 fixed method of reaction to the introduction of the food, that is not 

 easily changed. In the dog which has digested starch for a month, the 

 pancreatic juice is not readily changed back to that adapted to the diges- 

 tion of meat. As a result, definite organs will in the course of time have 

 left open to them only certain limited possibilities of variation due 

 to the development of something corresponding to the "action system" 

 in behavior. Thus, in the pancreas, there will not exist unlimited possi- 

 bilities as to the chemical changes that may occur. Its "action system" 

 will be limited perhaps to the production of varied quantities of a cer- 

 tain set of enzymes, amylopsin, trypsin, etc. The proper selection 

 of these few possibilities will then occur by the method sketched. When 

 digestion is disturbed by food that is not well digested, variations in 

 the production of the different enzymes will be set in train, and one of 

 these will in time relieve the difficulty, through the more complete diges- 

 tion of the food. Thereupon the variations will cease, since their cause 

 has disappeared. By still more complete fixation of the chemical re- 

 sponse, through the law of the readier resolution of physiological states 

 after repetition, or the analogue of this law, an organ or organism may 



