170 'Journal of Comparative Neurology and Psychology. 



Osmic acid i . 00 per cent, 5 parts 



Chromic acid 0.25 per cent, 3 parts 



Hydrochloric acid o.io per cent, 2 parts 



After washing for twenty-four hours in running water, the speci- 

 men was transferred for twenty-four hours to the following solu- 

 tion (B): 



Glycerine 10 parts 



50 per cent alcohol 20 parts 



Hydrochloric acid 0.09 parts 



After this treatment, the specimens are preserved in solution 

 (C): 



Glycerine 10 parts 



50 per cent alcohol 20 parts 



This last solution (C) should be renewed once or twice at inter- 

 vals of twenty-four hours. Thick nerves were slit longitudinally 

 with a razor, after they had been in solution (A) for two or three 

 hours. This was done to assist the penetration of the fluid. The 

 specimens were teased in solution (C). 



TABLE 2. 



Data on the specimens of Rana pipiens used in this investigation. Entries arranged 

 in the order of increasing body length. V, ventral; D, dorsal. 



The technique just given, fails however to yield satisfactory 

 results when applied to the nerve roots of the III or IX nerve 

 as the fibers become brittle and distorted. Moreover, the roots 



