I30 HODGE. [Vol. VII. 



our study, extremes are naturally of more interest. The ideal 

 would be to follow a living nerve cell during stimulation from 

 the normal resting state to the condition of extreme fatigue. 

 This I have not succeeded in doing to entire satisfaction as yet. 

 But it is possible, in the study of a section, to find a fairly good 

 substitute for the ideal. We see some cells which are not 

 affected at all ; and this we should expect, because it is impos- 

 sible to stimulate all the fibres going to a ganglion without 

 cutting so close as to endanger its blood supply. Next, we find 

 cells that are slightly worked. In the even outline of their 

 nuclei there may be here and there a slight indentation, and the 

 nucleus may stain a shade darker ; now and then a small 

 vacuole makes its appearance in the cell protoplasm. These 

 nuclei may have shrunken five or ten per cent. And so we 

 pass, by all degrees of difference, to cells which show extreme 

 fatigue. And here the protoplasm is riddled with vacuoles, and 

 the nucleus has shrunken to a densely staining speck, which 

 must have lost seventy-five to eighty per cent of its original 

 volume. 



I may close this section with the concluding sentences of a 

 former paper. We have, then, " as a result of electrical stimu- 

 lation : — 



'M. For the nucleus : i. Marked decrease in size. 2. Change 

 from a smooth and rounded to a jagged, irregular outline. 

 3. Loss of open reticular appearance with darker stain. 



'' B. For the cell protoplasm: i. Slight shrinkage in size. 

 2. Lessened power to stain or to reduce osmic acid. 3. Vacuo- 

 lation. 



" C. For the cell capsule: Decrease in size of the nuclei" 

 (24, p. 397). 



V. Process of Recovery from Fatigue. 



At the point in the investigation reached at the close of the 

 last section, the objection was raised that just such appearances 

 had long been known to occur in pathological conditions of the 

 nervous system. It is true that they resemble changes hitherto 

 described as pathological ; but up to the present no attempt has 

 been made to distinguish changes due to fatigue from those 

 caused by disease, and on a priori grounds we should expect 



