GANGLION CELLS IN THE SYMPATHETIC SYSTEM 277 



sympathetic (cervical, thoracic, lumbar) components seems in 

 the rabbit to be justified by morphological differences in the gan- 

 glion cells, as well as by the interval which, in the central nervous 

 axis, separates the cells of origin of the two divisions. 



In the group of rodents there appears to be considerable vari- 

 ation in the relative abundance of these binucleate cells in the 

 sympathetic ganglia. Apolant ('96) reported that the rabbit and 

 guinea-pig showed them to a marked degree, while it was excep- 

 tional to find a sympathetic cell with two nuclei in the rat, mouse 

 and squirrel. We are able to supplement Apolant's observations 

 ■ to the extent of increasing by two the list of rodents in which 

 binucleate sympathetic cells are present. We have found them 

 well represented in the muskrat and porcupine. The greatest num- 

 ber of such cells appears to be possessed by the rabbit and guinea- 

 pig, with the muskrat and porcupine following in the order in 

 which they are named. No binucleate cells were seen in the trunk 

 autonomic ganglia of the rat, mouse, thirteen-lined spermophile 

 and prairie dog, although it is possible that a few exist. 



SU.MMARY 



1. Sympathetic ganglion cells of the cat prepared by the Cajal 

 silver-nitrate method show both DogieFs ''motor type" of cell 

 with heavy dendrites and his ''sensory type" with slender den- 

 drites. They also show cells with intermediate structural char- 

 acters connecting the two "types." On the basis of external cell 

 morphology we cannot say, therefore, that two distinct kinds of 

 elements exist in the sympathetic ganglia. The "types" of Do- 

 giel are, in our opinion, to be regarded as extremes of the variation 

 which occurs among the multipolar sympathetic cells. 



2. Sympathetic ganglion cells of the rabbit prepared by the 

 Nissl method present a quite constant picture of the chromato- 

 phile bodies, which tend to be arranged near the periphery of 

 the cell-body. The cells cannot be divided by this feature of 

 their internal morphology into two well defined groups. 



