430 



THE CENTRAL NERVOUS SYSTEM. 



rones, the cell-bodies and dendrites of which are grouped to form 

 the sympathetic ganglia, form terminal links in nerve or neurone 

 chains ; the second link of these chains is formed by neurones the 

 cell-bodies of which are situated in the spinal cord or medulla, the 



Fig. 344. From section of sympathetic ganglion of turtle, showing white rami 

 fibers wound spirally about a large process of a unipolar cell, and ending in pericellular 

 plexus (Huber, Journal of Morphology, 1899). 



neuraxes leaving the cerebrospinal axis through the white rami as 

 small medullated nerve-fibers, which terminate in pericellular plex- 

 uses inclosing the cell-bodies of the sympathetic neurones. 



Large medullated nerve -fibers, the dendrites of spinal ganglion 

 neurones, reach the sympathetic ganglia through the white rami. 



Fig. 345. From section of sympathetic ganglion of frog, showing spiral fiber (white ramus 

 fiber) and pericellular plexus (Huber, Journal of Morphology, 1899). 



They make, however, no connection with the sympathetic neurones, 

 but pass through the ganglia to reach the viscera, where they ter- 

 minate in special sensory nerve-endings or in free sensory nerve- 

 endings. 



