474 ■^- ^- y^nnings. 



processes are held to be of a character essentially different from 

 anything found in the inorganic world. 



Nowhere is regulation more striking than in the behavior of 

 organisms. Indeed, the processes in this field have long served 

 as the prototype for regulatory action. The organism moves and 

 reacts, on the whole, in ways that are advantageous to it. If it 

 gets into hot water, it takes measures to get out again, and the same 

 is true if it gets into excessively cold water. If it enters an injuri- 

 ous chemical substance, it at once changes its behavior and 

 escapes. If it lacks material for its metabolic processes, it sets 

 in operation movements which secure such material, suspending 

 these movements when the lack is fully supplied. If it lacks 

 oxygen for respiration, it moves to a region where oxygen is 

 found. If injured it flees to safer regions. In innumerable 

 details it does those things which are good for it, and this is as 

 true of the Protozoan as of the Metazoan. It is plain that behavior 

 depends largely on the needs of the organism, and is of such a 

 character as to satisfy these needs. In other words, behavior is 

 adjustment or regulation. 



There seems no reason to think that regulation in behavior is 

 of a different character from that found elsewhere. But nowhere 

 else is it possible to perceive so clearly how regulation occurs. 

 In the behavior of the lowest organisms we can see not only what 

 the animal does, but precisely how this happens to be regulatory. 

 The method of regulation lies open before us. This method is of 

 such a character as to suggest the possibility of its application 

 to other fields; in other words, it suggests a possible general 

 explanation of the method of regulation. This suggestion the 

 present paper attempts to develop. 



In the lower, unicellular, organisms where we can see just how 

 regulation occurs, the process is as follows. Anything injurious 

 to the organism causes changes in behavior. These changes 

 subject the organism to new conditions. As long as the injurious 

 condition continues, the changes in behavior continue. The first 

 change in behavior may not be regulatory, nor the second, nor 

 the third, nor the tenth. But if the changes continue, subjecting 

 the organism successively to all possible different conditions, a 

 condition will finally be reached that relieves the organism of the 

 injurious action, provided such a condition exists. Thereupon 

 the changes in behavior cease, and the organism remains in the 



