358 THE SOLIDS. 



those of the spinal cord are usually very large, irregular in 

 form, and are furnished with numerous prolongations. 



These cells are highly and uniformly granular : they fre- 

 quently contain pigmentary matter, and enclose a nucleus, 

 which again is provided with i^s nucleolus, and both of which 

 are remarkable for their exceeding brilliancy. 



Ganglion cells are doubtless connected with the secretion, 

 of the nervous element or fluid : the use of the prolongations 

 with which they are furnished, and the precise relation of 

 these with the adjacent structures, the smaller secreting cells 

 and the nerve tubules, is not yet well ascertained: it has 

 been conjectured, however, that the caudiforrn processes are 

 directly continuous with the tubules ; a view which is 

 certainly incorrect. 



Mixed up with the ganglion cells wherever met with, but 

 especially with those occurring in the grey matter of the 

 cerebellum and spinal cord, a considerable number of 

 branched and nucleated fibres may be seen similar in ap- 

 pearance and structure to those of unstriped muscle, and 

 more particularly resembling the gelatinous filaments of the 

 sympathethic system, from which they in all probability 

 really proceed. 



There is a second description of ganglion cell, not con- 

 tained in either the brain or spinal cord, but found in the 

 various ganglia, as the Casserian, Ottic, Opthalmic, Spinal, 

 &c., formed in connection with the nerves of the cerebro- 

 spinal and sympathethic systems, and which may be here 

 described. 



These cells resemble the ganglion corpuscles already 

 noticed in their general structure, but differ from them 

 in form, being more or less round in shape, and destitute 

 of the branched processes belonging to the latter. (See 

 Plate XLV. fig. 4.) 



The mode of multiplication of ganglion cells is not well 

 understood: it is possible that the numerous granules con- 

 tained in each are the germs of the future cells. Adhering 

 to the surface of many of the larger ganglion cells of the 

 second form, a number of nucleated particles or lesser cells 



