NERVUS TERMINALIS: MAMMALS 27 



It will be noted that both myelinated {my.) and unmyelinated 

 (unmy.) fibers are present. The axis cylinders of the myelinated 

 fibers were stained a darker orange color than were the myelin 

 sheaths surrounding them. The processes of the unmyelinated 

 fibers were quite black and stood out distinctly. One of the 

 latter (a), which comes from the direction of the central connec- 

 tion of the nerve, divides into two smaller fibers which in turn 

 subdivide into terminations with small varicosities, and which 

 form simple pericellular baskets on two of the nerve cells shown. 



Several classifications, both of ganglion cells and of sympa- 

 thetic cells, have been made by investigators, notably by Cajal 

 ('05) Dogiel ('08), and Ranson ('12) for the former; and by 

 Cajal ('05), Carpenter and Conel ('14), Dogiel ('96), Michailow 

 ('11), and others for the latter type. There is considerable in- 

 dividual variation among the ganglion cells observed in the ter- 

 minalis clusters, and they come within one or the other of these 

 classifications. Still, for purposes of description it is convenient 

 to designate the types observed according to the number of proc- 

 esses they possess as unipolar, bipolar, and multipolar. A few 

 binucleated cells were seen in the cat, but aside from the num- 

 ber of nuclei, they resembled the other cells of the several varie- 

 ties and will not be treated separately. 



(a) Unipolar cells. Most of the unipolar cells observed re- 

 semble those usually considered characteristic of the spinal 

 ganglia. The body of the cell (figs. 5, 10, 18) is ovoid or spheri- 

 cal, with a rather large nucleus. The single process, which usu- 

 ally stained brown near the cell body, becomes darker as it 

 assumes a smaller diameter in its course away from the peri- 

 karyon. In those cases in which it was possible to follow it for 

 any distance, it divides into two processes, one directed in the 

 general direction of the central connection of the nerve, the 

 other peripherally as respects this connection. No marked dif- 

 ference in size of these two divisions was noted, although that 

 which appeared to be the central process was usually slightly 

 smaller in diameter. It must be understood that only the gen- 

 eral direction of the course of these fibers is indicated, because of 

 the various directions different strands of the plexus assumed. 



