chap. 5ux.] THE CEREBRO-SPINAL GANGLIA. 165 



fibre. The capsule of the ganglion cell is continued 

 on the axis cylinder process, arid, farther on, on the 

 medullated nerve-fibre, as the neurilemma ; while the 

 endothelial plates of the capsule pass into the nerve 

 corpuscles lining the neurilemma, their 

 number greatly diminishing (Fig. 95). 



221. In the rabbit this medullated 

 nerve-fibre at its first node of Ranvier, 

 which is not at a great distance from 

 the ganglion cell, divides into two me- 

 dullated nerve-fibres in the shape of a 

 T ', one branch is supposed by Ranvier 

 to pass to the cord, the other to the 

 periphery. In man, this T-shaped 

 division has also been observed by 

 Retzius, but it cannot be said with 

 certainty that in rabbit or man 

 every axis cylinder process shows this 

 T-shaped division. Retzius observed 

 this T-shaped division also in the 

 Gasserian, geniculate, and vagus gan- 

 glia in man. 



The ganglion cells are not unipolar 

 in all cerebral ganglia ; in the ciliary 

 and otic ganglia there are a good many 

 ganglion cells which are multipolar. 



222. Numerous ganglia of micro- 

 scopic size are to be found in the 

 sub-maxillary (salivary) gland ; they 

 are of different sizes, and are in 

 reality ganglionic enlargements of 

 larger or smaller nerve-bundles. Each 

 ganglion is invested in connective 

 tissue continuous with the perineu- 



rium, and the ganglion cells are unipolar, and of the 

 same nature as those described above, each being 

 possessed of an axis cylinder process, which becomes 



Fig. 95. An iso- 

 lated Ganglion 

 Cell of a Spinal 

 Gan gli on o f 

 Toad. 



The axis cylinder 

 a becomes 

 formed into 

 medullated nerve- 

 fibre. The capsule 

 of the cell is pro- 

 longed as the neu- 

 rilemma of the 

 nerve-fibre. (Key 

 and Retzius.) 



process 

 transfo 



