tions were made of the si)inal ganpflia and eord, and 

 compared with simikir preparations from well-fed 

 dogs. Among other changes, and preceding degen- 

 eration or atrophy, he finds that the cells shrink and 

 become vacuolated. Upon the death of the animal the 

 nuclei had disappeared from many of the cells, llie 

 nerve fibers, however, appeared normal. 



But little has been done upon the purely physiologi- 

 cal histology of the ganglion cell. 



In 1869, Svierczewski' described changes in the liv- 

 ing cells of the frog's sympathetic ganglia, changes in 

 part probably due to functional activity of the cell. 

 He kept the cells alive in aqueous humor or lymph 

 under the microscope, and subjecting them to different 

 conditions, observed the effects. It is significant to 

 note that his attention centered upon the nucleus and 

 its contents. The nucleoli were seen to wander about 

 in the nucleus, sometimes in the most lively fashion, 

 for as long as twenty -four holirs. On exposing the 

 cells to carbon dioxide, a finely granular precipitate 

 suddenly formed within the nucleus, which redissolved 

 on treatment with oxygen or hydrogen (" paraglobulin- 

 reaction "). This process was accompanied, under cer- 

 tain conditions, by a marked shrinking of the nucleus, 

 its rounded form being altered to an angular or " zick- 

 zack" outline, the nucleolus being at the same time 

 lost to view. 



Somewhat similar observations were made by Freud' 

 upon the living ganglion cells of Astacus. He describes 

 shreds and angular-shaped particles which change 

 form and position in the nucleus. 



' Zur Physiologie des Kerns und Kernkorperchens der Nerven- 

 zellen des Sympatheticus. Svierczewski. Centralblattfiirdiemedi- 

 cinischen Wissenschaften, 1869, p. 641. 



' Ueber den Ban der Nervenfasern und Nervenzellen beim Fliiss- 

 krebs. Wiener Sitzgb. 1882, p. 1. 



