THE NERVOUS SYSTEM. 



77 



NERVE CELLS OR CORPUSCLES. 



The vesicular nervous substance contains, as its name implies, vesi- 

 cles or corpuscles, in addition to fibres; and a structure, thus composed 

 of corpuscles and inter-communicating fibres, constitutes a nerve-centre; 

 the chief nerve-centres being the grey matter of the brain and spinal cord, 

 and the various ganglia. In the brain and spinal cord a fine stroma of 



FIG. 312. Two striped muscle-fibres of the hyoglossus of frog, a, Nerve end-plate; 6, nerve 

 fibres leaving the end-plate; c, nerve-fibres, terminating after dividing into branches; d. a nucleus in 

 which two nerve-fibres anastomose. X 600. (Arndt.) 



neuroglia (p. 34, Vol. I.), extends throughout both the fibrous and vesicular 

 nervous substance, and forms a supporting and investing framework for 

 the whole. 



The nerve-corpuscles which give to the ganglia and to certain parts 

 of the brain and spinal cord the peculiar greyish or reddish-grey aspect 

 by which these parts are characterized, are large, nucleated cells, filled 

 with a finely granular material, some of which is often dark like pigment: 



