102 HANDBOOK OF PHYSIOLOGY. 



witfc Wlfltliitt is continuous. This process is the neuraxon. 

 In bipolar* cells due pbie'niay. be continuous with a inednllated fibre, and 

 th^ot^^;^iih>^aau-^eiiuil^ed one, or both poles may pass into fibres 

 of 'the' one 'or the other kind. 



Ganglion-cells are generally inclosed in a transparent membranous 

 capsule similar in appearance to the external nucleated sheath of nerve- 

 fibres; within this capsule is a layer of small flattened cells. 



The process of a nerve-cell or neuraxon which becomes continuous 

 .nth a nerve-fibre is always unbranched as it leaves the cell. It at first 

 has all the characters of an axis-cylinder, but soon acquires a medullary 



Fig. 105A. An isolated sympathetic ganglion-cell of man, showing sheath with nucleated-cell 

 lining, B. A. Ganglion-cell, with nucleus and nucleolus. C. Branched process or dendrite. D. 

 Unbranched process or neuraxon. (Key and Retzius. j x 750. 



sheath, and then may be termed a nerve-fibre. This continuity of nerve- 

 cells and fibres may be readily traced out in the anterior cornua of the 

 gray matter of the spinal cord. In many large branched nerve-cells a 

 distinctly fibrillated appearance is observable; the fibrillas are probably 

 continuous with those of the axis-cylinder of a nerve. 



Other points in the structure of nerve-cells will be mentioned under 

 the account of the central nervous system. 



Nerve Terminations. 



Nerve-fibres terminate peripherally in four different ways: 1, by the 

 terminal subdivisions which pass in between epithelial cells, and are 



