164 



ELEMENTS OF HISTOLOGY. [Chap. xix. 



the branches of the acoustic nerve, the sub maxillary 

 ganglion, &c. possess a capsule of fibrous connective 

 tissue continuous with the epineurium of the afferent 

 and efferent nerve trunks. The interior of the ganglion 

 is subdivided into smaller or larger divisions, contain- 

 ing nerve bundles with their perineurium, or larger 

 and smaller groups of ganglion 

 cells. In the spinal ganglia 

 these latter are generally dis- 

 posed about the cortical part, 

 whereas the centre of the 

 ganglia is chiefly occupied by 

 bundles of nerve-fibres. 



220. The ganglion cells differ 

 very greatly in size, some being 

 as big, and bigger, than a large 

 multipolar ganglion cell of the 

 anterior horn of the cord, others 

 much smaller. Each cell has 

 a large oval nucleus, including 

 a network, with one or two 

 large nucleoli. Its substance 

 shows a distinct fibrillation. 

 Each cell of the ganglia in man 

 and mammals is unipolar (Fig. 

 94), flask or pear-shaped, and 

 invested in a hyaline capsule, 

 lined with a more or less con- 

 tinuous layer of nucleated endo- 

 thelial cell-plates. The single 

 process of the ganglion cell is 

 finely and longitudinally stri- 

 ated, and is an axis cylinder 

 process. Immediately after 

 leaving the cell body it is much 

 convoluted (Retzius) ; then it gets invested in a 

 medullary sheath i.e., it becomes a medullatod nerve- 



94. A large and small 

 Ganglion Cell of the Gang- 

 lion Gassed of the Rabbit. 



The axis cylinder, alter leaving 

 the cell, becomes convoluted 

 and transformed into a medul- 

 lated nerve-fibre, which divides 

 into two medullated fibres. 

 (Key and Eetzius.) 



