348 BEHAVIOR OF THE LOWER ORGANISMS 



largely lose its power of varying its chemical behavior and thus be 

 unable to meet new conditions in a regulative way. A condition com- 

 parable to the production of a fixed reflex in behavior will result. 



It is perhaps more difficult to apply the method of regulation above 

 set forth to processes of growth and regeneration. Yet there is no logi- 

 cal difficulty in the way. The only question would be that of fact, 

 whether the varied growth processes necessary do, primitively, occur 

 under conditions that interfere with the physiological processes. When 

 a wound is made or an organ removed, is the growth process which 

 follows always of a certain stereotyped character, or are there variations? 

 It is well known, of course, that the latter is the case. In the regenera- 

 tion of the earthworm, Morgan (1897) finds great variation; he says 

 that in trying many experiments, one finds that what ninety-nine worms 

 cannot do in the way of regeneration, the one hundredth can. The 

 very great variations in the results of operations on eggs and young 

 stages of animals are well known. Removal of an organ is known to 

 produce great disturbance of most of the processes in the organism, and 

 among others in the process of growth. 



It appears not impossible then that regulation may be brought about 

 in growth processes in accordance with the same principles as in be- 

 havior. A disturbance of the physiological processes results in varied 

 activities, and among these are varied growth activities. Some of these 

 relieve the disturbance; the variation then ceases and these processes 

 are continued. In any given highly organized animal or plant the dif- 

 ferent possibilities of growth will have become decidedly limited ; and it 

 is only from this limited number of possibilities that selections can be 

 made. In some cases, by the fixation of certain processes through the 

 analogue of the law of the readier resolution of physiological states, 

 the organism or a certain part thereof will have lost the power of respond- 

 ing to injury save in one definite way. Under new conditions this one 

 way may not be regulatory, yet it may be the only response possible. 

 Thus may result the formation under certain conditions of heteromorphic 

 structures, a tail in place of a head, or the like, from a part of the 

 body that (in normal development perhaps) is accustomed to produce 

 such an organ. This would again correspond to the production of a 

 fixed reflex action in behavior, even under circumstances where this 

 action is not regulatory. 



It appears to the writer that the method of form regulation recently 

 set forth in a most suggestive paper by Holmes (1904) is in agreement 

 with the general method of regulation here set forth, and may be consid- 

 ered a working out of the details of the way in which growth regulation 

 might take place along these lines. Holmes has of course emphasized 



