TISSUES OF THE BODY. 



317 



protoplasm processes and penetrating the body of a cell, they are collected 

 together in the latter, and pass out as an axis cylinder, are questions 

 still undecided. 



Fig. 308. Ganglion cell from the anterior conra of the spinal cord of the 

 ox (after Schultze). , axis cylinder; 6, processes sent off by the cell. 



REMARKS. See Beale's treatise in the Phil. Trails, for the year 1863, part ii. 

 p. 543. Many other German observers agree with us in our view of the probably 

 elastic nature of the spiral fibres. 



180. 



Having become acquainted with the two kinds of form-elements of the 

 nervous system, let us now turn to the consideration of their general 

 arrangement in the peripheral nervous apparatus. 



The nerves of the brain and spinal cord, differing in their white colour 

 from those of the sympathetic system, which are usually grey or greyish 

 red, become clothed with a delicate envelope at their exit from the 

 nervous centres. This covering receives another addition from the dura 

 mater of connective-tissue bundles in its passage through the latter, and, 

 thus strengthened, constitutes what was formerly known as "neurilemma," 

 but which we will designate from henceforth " perineurium " (1). 



