THE NERVE CELL 



183 



These bodies are known as the chromaphyllic masses, the tigroid bodies 

 being another and perhaps more convenient name. These masses are 

 not homogeneous, but are composed of individual granules that appear 

 to be characteristic organs of the nerve cell. We shall call the granules 

 neurochondria to distinguish them from the other granules that are 

 sometimes found in the nerve cell. 



That the neurochondria are active organs of nerve work may be 

 surmised from the changes that take place in them under different physio- 

 logical conditions. Poisons and stimulants, as well as fatigue and disease, 

 cause marked changes in their amount and distribution. They are 

 possibly masses of food material for the trophic processes of the cell or 



imp. c. 



fev$^^>^>t ^m^^Mii^^. 



FlG. 160. Dorsal giant nerve cell from cord of young flounder, Pseudopleuronectes. Three 

 nuclei. The chromophyllic substance in two forms, a finely granular deposit in the cyto- 

 plasm and larger spindle-shaped bodies in both cytoplasm and part of the implantation 

 cone. Fibrillar nature of implantation cone (imp.c.) well shown. X 700. 



even to more directly support the nervous activities themselves. Not all 

 nerve cells appear to possess these structures. It is probable, however, 

 that, considering their almost universal presence in the various nerve 

 cells, they exist in these apparent exceptions as diffused or invisible 

 structures. 



The neurochondria are individually so small as to be almost invisible. 

 They are visible, usually, because they are arranged in the masses spoken 

 of above, the tigroid bodies (see Figs. 157 and 161). These bodies are 

 arranged through the cytoplasm (neuroplasm) with an apparent view to 

 meeting two conditions, a fairly general distribution and the avoiding 

 of interference with the courses of the neuro-fibrils. This results in some 

 such figure as is seen in Figures 157 or 161. In this last, which is a nerve 

 cell from the cord of a fish, the distribution of the neurochondria in 



