346 BEHAVIOR OF THE LOWER ORGANISMS 



processes of the organism. Is it possible that interference with the physio- 

 logical processes may induce changes in other activities, — in chemical 

 processes, in growth, and the like, — and that one of these activities is 

 selected, as in behavior, through the fact that it relieves the interference 

 that caused the change ? 



There is some evidence for this possibility. Let us look, for example, 

 at regulative changes in the chemical activity of the organism, such as 

 we see in the acclimatization to poisons, in the responses to changes in 

 temperature, or in the adaptation of the digestive juices to the food. 

 What is the material from which the regulative conditions may be se- 

 lected? One of the general results of modern physical chemistry is 

 expressed by Ostwald (1902, p. 366) as follows: "In a given chemical 

 structure all processes that are so much as possible, are really taking 

 place, and they lead to the formation of all substances that can occur 

 at all." Some of these processes are taking place so slowly that they 

 escape usual observation ; we notice only those that are conspicuous. 

 But in its enzymes the body possesses the means (as Ostwald sets forth) 

 of hastening any of these processes and delaying others, so that the gen- 

 eral character of the action shall be determined by the more rapid pro- 

 cess. Such enzymes are usually present in the body in inactive forms 

 (zymogens), which may be transformed into active enzymes by slight 

 chemical changes, thus altering fundamentally the course of the chemi- 

 cal processes in the organisms. 



It is evident, then, that the organism has presented to it, by the condi- 

 tion just sketched, unlimited possibilities for the selection of different 

 chemical processes. The body is a great mass of the most varied chemi- 

 cals, and in this mass thousands of chemical processes, in every direction, 

 — all those indeed that are possible, — are occurring at all times. There 

 is then no difficulty as to the sufficiency of the material presented for 

 selection, if some means may be found for selecting it. 



Further, it is known that interference with the physiological pro- 

 cesses does result in many changes in the internal activities of the organ- 

 ism, as well as in its external movements. Intense injurious stimula- 

 tion causes not merely excess movements of the body as a whole, but 

 induces marked changes in circulation, in respiration, in temperature, 

 in digestive processes, in excretion, and in other ways. Such marked 

 internal changes involve, and indeed are constituted by, alterations of 

 profound character in the chemical processes of the organism. These 

 chemical changes are sometimes demonstrated by the production of new 

 chemicals under such circumstances. Furthermore, it is clear that the 

 internal changes due to interference with the physiological processes are 

 not stereotyped in character, but varied. Under violent injurious stimu- 



