150 



NERVOUS TISSUES 







FIG. 166. SECTION THROUGH THE DORSAL 

 ROOT GANGLION OF THE FIRST THORACIC 

 NERVE OF A CAT. 



The ganglion cells contain a large vesicu- 

 lar nucleus, with nucleolus, and are en- 

 veloped by a nucleated capsule. Several 

 medullated fibers appear among the gan- 

 glion cells. (From Barker, after Hodge.) 



frequently proximally convoluted and, 

 after branching in T-shape fashion, 

 passes out of the ganglion to become 

 the axis cylinder of a medullated nerve 

 fiber, and (2) cells with a slender axon 

 which breaks up within the ganglion 

 and whose terminal arborizations form 

 a pericapsular plexus around the cell 

 capsule; from this plexus fine end 

 branches penetrate the capsule to form 

 a pericellular arborization about the 

 nerve cell itself. The cells of this lat- 

 ter type suggest association neurons 



cell and its processes, being con- 

 tinuous with the neurolemma. 

 The capsule is not, however, as 

 a rule, closely applied to the 

 cell, but leaves a narrow inter- 

 val which is occupied by lymph 

 or 'tissue juice/ 



In their structure the gang- 

 lion ic neurons do not appear to 

 differ in any way from other 

 neurons. The large vesicular 

 nucleus with its distinct nucleo- 

 lus readily distinguishes these 

 cells from those of neighboring 

 tissues. 



The studies of the ganglion 

 cells by Dogiel, Eanvier, and 

 Cajal have done much to ex- 

 plain the relations of these cells 

 to each other, especially in the 

 sympathetic system, where they 

 were formerly but little under- 

 stood. In the spinal ganglia 

 Dogiel (Anat. Anz., 1896) de- 

 scribed two types of ganglion 

 cells: (1) a unipolar cell in 

 which the axon is thick and 



FIG. 167. A NERVE CELL FROM A 

 SECTION OF A HUMAN GAS- 

 SERIAN GANGLION. 

 C, capsule. Nissl's stain. X 500. 



