106 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



system, nerve terminations formed in tissues and 

 organs throughout the whole body. 



General Considerations. Nerve cells are so highly 

 specialized that their multiplication after birth is un- 

 known. We never, therefore, find tumors of nerve 

 cells. If a nerve cell is cut, the axis cylinder re- 

 moved from the nerve cell dies while the end that 

 is still attached to the cell regenerates and may 



Fig- 75 Neurogliar cells: a y from spinal cord of embryo cat; 'ft, from 

 brain of adult cat; stained in chrome-silver (Bohm and Davidoff). 



restore the lost part. Surgeons unite the ends of a 

 cut nerve so that the axis cylinder may develop along 

 the old nerve trunk which becomes a path of least 

 resistance. 



In amputations the cut nerve may grow into a 

 tumor, called a neuroma. Such a tumor would con- 

 sist of nerve fibers and the accompanying connective- 

 tissue elements. Injury to nerve cells, such as 



