EEPORT OF COMMISSIONERS OF INLAND FISHERIES. 309 



process of regeneration or for the process of growth involved in the 

 molting activities. 



4. The fact that the regenerative process does not respond with 

 equal readiness to mutilations made at different times in the molting 

 periods appears especially significant, for two reasons: 



(a) It suggests the existence of an important internal factor 

 influencing the process of regeneration. For, whether a regeneration 

 of the limbs shall succeed a mutilation or not is apparently largely 

 determined by the condition of the molting activities; so that, when 

 the molting process is approaching the climax of the molting period, 

 an inhibiting influence is exerted upon the regenerative process. 



While the present data may not throw much light upon the nature 

 of this inhibiting influence, it is interesting to note the modification 

 which they seem to necessitate in the theory of the distribution of 

 energy to the regenerating cells. Since the energy for regeneration 

 does not seem to be equally available at later stages of the molting 

 period, it appears that there is a tendency toward an increasing stability 

 or permanence in the channels of energy distribution, so that as the 

 molting process approaches its culmination it becomes more and more 

 difficult to divert energy into the celhdar process of regeneration. 



It is evident, however, that a different conclusion is also possible. 

 For the regenerating cells may fail to respond readily to mutilations 

 made late in the molting period, not because the energy of food 

 material is unavailable for assimilation, but rather, because the power 

 of assimilation in the cells themselves has been modified. This latter 

 conclusion brings us to the recognition of an alternative hypothesis 

 for the relation between regeneration and the process of molting, 

 namely, that the interaction between the two processes may consist 

 n a direct variation in the power of assimilation in the cells concerned, 

 as well as a variation in the material available for assimilation. 



(b) The fact that the process of regeneration does not respond 

 with ec][ual readiness to mutilations made at later stages in the molt- 

 ing period raises the question as to whether there is a tendency in 



