28 Journal of Comparative Neurology. 



originally by proliferation and moniliform concrescesce/ We 

 here have an instance where the protoplasm of the cells has be- 

 come specialized and the nuclei switched out of the circuit and 

 apparently related to the process of forming the cell wall. But, 

 in spite of the specialization implied in the production of an 

 organ for nervous conveyance alone, it appears that the early 

 nature of the cells is dormant rather than lost, so that in the 

 case of injury and the consequent degeneration of the myelin 

 and axis 'cylinder, the nuclei, with the small portion of less 

 specialized protoplasm associated, return to the embryonic state 

 and repeat the process of neuro-proliferation, after which the 

 new channel is organized from the center outward and the nu- 

 clei return to their parietal position. It is more than probable 

 that a similar rejuvenescence is possible in the case of other 

 tissues also. 



We have many instances of the same kind of differentia- 

 tion within the cell. Take as an illustration the formation of 

 glands in the skin of the frog, where a follicle is formed and 

 then the several component cells are fused, the outlines being 

 lost, and only the small nuclei which remain in the thin parietal 

 layer of less altered protoplasm remain to indicate that the 

 gland is really polycellular. It would be interesting in this case 

 to institute experiments on the possibility of rejuvenescence of 

 such cells. 



In the application of the neural equilibrium theory to prob- 

 lems of heredity it would seem that there is a large and profit- 

 able field. Without attempting details in this direction, it may 

 be pointed out that this point of approach renders unneces- 

 sary a vast deal of the most profitless theorizing in reference to 

 heredity. If the neural and somatic forms of reaction are not 

 absolutely unlike, but on the contrary are parts of a common 

 vital type of energy (or rather force) and if it be admitted that 

 the processes of nutrition may be and are influenced by the 



' The nuclei of the ending of the motor nerve on the muscle offer interest- 

 ing collateral evidence. See the article by Dr. Huber in the last number of this 

 Journal 



