GANGLION CELLS IN THE SYMPATHETIC SYSTEM 275 



ures 9 to 13 will show how easity recognizable these differences 

 are. The first two drawings show sensory cell-bodies from a cra- 

 nial and a spinal ganghon with their numerous, small Nissl flakes 

 evenly distributed throughout the cytoplasm. Figures 11 to 13 

 represent motor cell-bodies from the nuclei of origin of ventral- 

 root neurites in the gray substance of the spinal cord. Their less 

 numerous and much larger chromatophile bodies are in striking 

 contrast to those of the sensory cells. Furthermore, the recent 

 studies of Jacobsohn ('10) and IMalone ('13) show that in the 

 central nervous system afferent and efferent cells may often be 

 distinguished one from the other by means of the Nissl bodies, 

 which are, in general, relatively coarser in efferent cells. 



A study of Nissl preparations made from the thoracic, supe- 

 rior mesenteric, and coeliac ganglia of the rabbit has, however, 

 failed to reveal to us two types of sympathetic cells. The Nissl 

 picture presented is a very constant one (figs. 14 to 19). In gen- 

 eral the chromatophile bodies are intermediate in size between 

 those of sensory cerebro-spinal cells and those of motor cerebro- 

 spinal cells. They are often massed toward the peripher}^ of the 

 cell, with only a few scattered flakes in the more central region 

 around the nucleus (figs. 14, 16, 18, 19). This arrangement was 

 found to obtain in nearly all cells which were viewed in optical sec- 

 tion passing through their centers. Occasionally, however, cells 

 were seen in which the peripheral grouping was not pronounced, 

 the Nissl bodies being distributed fairly evenly throughout 

 the cytoplasm of the cell-body (figs. 15 and 17), but these cells 

 can hardly be said to form a distinct group. The characteristic 

 peripheral arrangement of the Nissl flakes in the majority of 

 sympathetic ganglion cells of the rabbit was observed by Eve 

 ('96) in his study of the physiology of the basophile constituents. 



An examination of the cranial autonomic ganglia showed us 

 that the Nissl picture is in these cells very similar to that seen in 

 the sympathetic cells proper. This is apparent from an inspec- 

 tion of figures 20, 21, and 22 which represent, respectively, ele- 

 ments from the otic, ciliary and sphenopalatine ganglia. Among 

 the cranial autonomic cells the perinuclear area frequently ap- 

 pears even more devoid of Nissl flakes than it does among the 

 cells of the sympathetic division of the system. 



