GANGLION-CELL AND NEKVE. 25 



important results already applicable. In the body of all ganglion-cells one 

 finds, after fixation with alcohol, a substance which stains with basic stains 

 and a substance which does not. The first appears in difEerent cells, and 

 probably in different conditions of the same cell, in variable structural 

 forms. One meets granules, threads, and spindles, as well as many other 

 regular and irregular forms, of which only a few are, through position or 

 form, well characterized (Eernkappen, Verzweigungskegel, u. s. w.). This 

 structural arrangement differs so greatly that Nissl has, within the ganglion- 

 cell genus, separated out a great many different cell-species. According to 

 this author, definite 'differences appear also within the nucleus, which he 

 utilized with the other characters in differentiating cells. If the ganglion- 

 cell suffers any injury — be it the influence of a poison, of unwonted activity, 

 or of a divided axis-cylinder — changes always arise within the stainable 

 substance. When the injury is intense the changes may lead to an almost 

 complete disappearance of the stainable substance. But if the nucleus re- 

 mains uninjured the integrity of the cell-substance may be restored. 



The study of this cell-change is of the very greatest importance. It 

 opens to us finally a glimpse into the inner changes which proceed during 

 cell-activity. 



Hodge, as well as Nissl, has done most creditable work in this field. 

 Hodge studied cells fatigued by direct stimulation or by stimulation through 

 the medium of the axis-cylinder; also cells in the condition of fatigue, — 

 ganglion-cells of bees after the day's work, — comparing them with rested 

 cells. He found that the stainable granules always decreased; that the 

 fatigued cell became more translucent; further, that it even became vacu- 

 olated. At the same time the volume decreased. On the last point, how- 

 ever, there is no unanimity of statement. 



These differences are conditioned upon the present state of the tech- 

 nique. Complete unanimity of statement exists on the relation of the 

 nucleus to fatigue. This always decreases in size, becomes serrated, and 

 takes a darker stain than the rested nucleus. 



Within the unstained substance the latest investigations by Becker, 

 Plemming, Dogiel, et al, have demonstrated a delicate fibrillated structure. 

 The appearance is as if each of the larger cells studied were traversed 

 in all directions by long, delicate threads, which pass in and out with the 

 cell-branches. Further, such threads do not always traverse the entire cell, 

 but pass out again into that branch located next to the one by which it 

 entered. Becker demonstrated this in the cells of the anterior horn. Only 

 the improved method made the presence of these fibrillse certain. Possibly 

 they will yield a foundation for a better knowledge of the function of the 

 ganglion-cell. Max Schultze drew attention to them, however, many years 

 ago. 



