NERVES. 



[ 638 ] 



NERVES. 



cord of the ox treated with carmine and 

 ammonia. 



In the grey, sympathetic, or ganglionic 

 nerves, the fibres of which are sometimes 

 called gelatinous fihres, the nerves are paler 

 than those of most of the cerebro-spinal 

 nerves, and they are scattered through 



Fig. 512. 



From the human sympathetic. A. Portion of a grey 

 fibre treated with acetic acid: a, fine nerve-tubes; o, 

 nuclei of Remak's fibres. Three ganglion-globules, 

 one with a pale process. 



Magnified 350 diameters. 



numerous longitudinal non-medullated fibres 

 (Remak's fibres), containing elongated nuclei 

 (fig. 512). 



N&'ve-cells, nerve-corpuscles, or ganglion- 

 globules are masses of fibrillar protoplasm, 



granular and faintly coloured ; they have a 

 nucleus and nucleolus. They are most nu- 

 merous in the cineritious or dark portions of 

 the nervous centres, and in the ganglia ; but 

 they are met with in the trunks and termi- 

 nal expansion of nerves, as the retina, &c. 

 Some are furnished with a nucleated capsule 

 (tig. 513, 2 a) ; this is easily seen in the 

 cells of the ganglia, but with difficulty in 

 those of the central organs. 



They are rounded, elongate, pyriform, or 

 angular (fig. 513). Some are simple, others 

 are furnished with one, two, or more simple 

 or branched processes ; hence they are 

 described respectively as uni-, bi-, or multi- 

 polar. Their contents are a soft, tenacious, 

 but fibrillar mass (fig. 513, 3), consisting of 

 a clear, homogeneous, proteine basis, and a 

 number of larger and smaller granules, as 

 well as a nucleus and nucleolus. In size 

 they are very variable, from 1-5000 to 1-500". 

 The granules are sometimes colourless, at 

 others yellow, brown, or black ; and occa- 

 sionally these are aggregated to form a 

 mass. 



A number of fine fibres radiating from 

 the nucleus and nucleolus may be seen 

 traversing the cell-substance, which con- 

 tains granular, yellow, or reddish-brown 

 pigment. Chloride of gold renders the 

 nucleus very distinct. Beale has shown 

 that two processes are given off from the 



Fig. 513. 



"N"erve-cells and fibres from the auditory nerve. 1. Nerve-cell with the origin of a fibre, from the anastomosis 

 between the facial and auditory nerve in the meatus auditorius externus of the ox: a, cell-membrane ; b, contents ; 



Magnified 350 diameters. 



