136 HODGE. [Vol. VII. 



interfibrillar substance is removed, whereas that of the nucleus 

 is too soft or delicate to resist the pressure of the lymph 

 about it. 



The ideal, in following the process of recovery in a nerve cell, 

 would be to watch continuously a living active cell for the 

 required length of time. For the present, however, we have 

 only specimens prepared by two good methods, taken so as to 

 give us presumably five steps in the process. 



As before remarked, the table gives but a meagre notion of 

 the facts. The processes of recovery are, in general, the reverse 

 of those of fatigue. The nucleus and protoplasm gradually 

 return to normal appearance. The protoplasm seems to recover 

 rapidly. At any rate, in the specimen which has rested six and 

 one-half hours, little trace of vacuolation is observable ; and this 

 is true of all those which have rested for a longer time. The 

 nuclei, on the other hand, recover slowly. After six and one- 

 half hours' rest they show a marked gain in size, but still retain 

 the dense stain characteristic of fatigue. Indeed, in this respect 

 the process of recovery is not entirely completed in all the nuclei 

 which have rested for twenty-four hours, it being still possible to 

 find a few large but densely stained nuclei. So far as it goes, my 

 observations, therefore, favor the view that granules arise within 

 the nucleus in some peculiar manner, although in a nerve cell 

 they are too small and ill-defined by any method I have used to 

 permit of seeing the manner of their migration into the cell pro- 

 toplasm, if, indeed, any such thing takes place. 



A study of nerve cells, thus, after long periods of complete 

 rest, has brought out a point of general interest to the histology 

 of the nervous system. An appearance often noted in nerve 

 histology has hitherto complicated all of our experiments. This 

 is the fact that individual cells in the same ganglion present such 

 great histological differences. Ranvier ^ calls attention to this 

 fact and proves that it cannot be due to the action of reagents, 

 but must express some difference between the cells themselves. 



1 Ranvier, Traite D' Histologie, Paris, 1889, p. 802: " How is it that a little gan- 

 glion, placed in a solution of ammonium bichromate, all the elements of which are 

 therefore submitted to the same influences, contains, side by side, cells modified in a 

 manner so widely different? This is a fact which we cannot yet explain, but upon 

 which we must insist, because we see it repeated in the spinal cord, the cerebrum, 

 the cerebellum, etc.; that is to say, in all organs containing ganglion cells." 



