108 ELEMENTARY PHYSIOLOGY. [x. 



process of mounting. If the nerve has been 

 kept long in ammonium bichromate the 

 medulla "will shew an indistinct network 

 stained yellow. 



d. The primitive sheath as a limiting circle. 



e. The arrangement of the fibres in bundles. 

 The perineurium around each bundle con- 

 tinuous with the endoneurium between the 

 fibres. 



B. Sympathetic Nerves. 



1. Out out from the fresh spleen of a large animal 

 (e.g. ox) a small piece of one of the large sjrmpa- 

 thetic nerves running alongside the blood-vessels. 

 Remove the connective-tissue sheath, and tease 

 out the nerve carefully in normal saline solution. 

 Note 



a. The scanty meduUated nerve fibres. 



h. The non-medullated nerve fibres consti- 

 tuting the bulk of the nerves : they are 

 fairly transparent, and often fibrillated, some 

 give off fibrillae. Add acetic acid to bring 

 out more distinctly the small elongated nuclei 

 which lie on them at short intervals. 



2. Take a small piece of the sympathetic nerve 

 from the neck of a freshly-killed rabbit, place it 

 in osmic acid 1 p.c. for five or ten minutes, wash 

 and stain with strong Frey's carmine or with 

 picrocarmine. Tease out in dilute glycerine. 



