202 HANSFORD MACCURDY 



The reticulate structure was lost, and the cytoplasm had shrivelled 

 away from the outer parts of the cell. The nucleus also shared 

 in these changes. The nuclear membrane had suffered a complete 

 collapse, while the nuclear network had disappeared. The 

 nucleolus apparently was more resistant than the other parts, 

 and only after longer periods than that shown in figure 2 did it 

 finally fail to stain and ultimately disappeared. 



Degeneration may be practically complete at the end of two 

 weeks, or it may be prolonged through a much greater period. 

 In addition to the changes in the large ganglion cells, man}^ of 

 the smaller cells undergo corresponding changes and disappear. 

 The ganglion is much reduced in size because of these changes. 

 Preparations made three to five days after the operation usually 

 showed but little change. After seven to fourteen days the changes 

 were quite evident . In some cases cells had lost their distinguishable 

 structures eighteen days after the nerves had been severed, while 

 other cells in the same ganglion were apparently only slightly 

 affected. The disappearance of individual cells in the midst of 

 cells which still remained apparently little affected is regarded as 

 strong evidence of true degeneration. 



On examining the results obtained in the first series of experi- 

 ments, it became evident that, although degeneration could 

 be demonstrated, the Nissl method had revealed only a part of the 

 changes which had occurred within the cells. Some method which 

 would show the changes in the finer structure of the cells and one 

 which would serve as a check on the previous experiments was, 

 therefore, sought. Since the picro-aceto-platino-osmic fluid of 

 vom Rath is known to demonstrate admirably the finer struct jres 

 of these ganglion cells in their normal condition, it was thought that 

 this treatment might also show the changes occurring in connec- 

 tion with the loss of function and consequent degeneration. Ac- 

 cordingly the ganglia were removed, in the manner described for 

 the Nissl method, from an individual in which the fifth ganglion 

 had been isolated twenty-nine days, and were immersed in vom 

 Rath's fluid for a period of forty-eight hours, washed in water, 

 dehydrated, cleared in xylol, imbedded in paraffine and cut into 

 sections 10/j. thick. Examination of the material revealed nerve 



