METHOD II. 



THE NISSL METHOD. 



A method devised especially to demonstrate the tigroid 

 masses or Nissl bodies of the nerve cell. 



SPECIAL REAGENTS REQUIRED. 



A. Fixing agent. — 96 per cent, alcohol. Ordinary absolute 

 (97-98 per cent.) may be used. 



B. Stain (Nissl's methylen blue). — 



Methylen blue {Methylenblau B. pat.), i .3 g. 

 White Castile soap (Venice soap), 0.7 g. 

 Distilled water, 332 cc. 



C. Differentiating fluid (" aniline alcohol "). — 



95 per cent, alcohol, go cc. 

 Aniline oil, ro cc. 



D. Clearing fluids . — 



1. Cedar oil-xylol, (I, E, p. 15). 



2. Oil of cajeput (pure). 



E. Mounting medium (" colophonium "). — A xylol or benzol 

 solution of "virgin rosin," a rosin nearly colorless and which is 

 plastic at, or just above, the temperature of the hand (90° F. or 

 32° C). 



PROCEDURE. 



1. To fix, place pieces of tissue (preferably 4-5 mm. thick) 

 into about 20 times their volume of 96 per cent, alcohol (A). 

 The pieces must be small to get the best results from alcohol as 

 a fixative. Tightly close the vessel and let remain for 12-24 

 hours. 



2. To dehydrate, transfer the tissue to about 20 times its bulk 

 of absolute alcohol for 40-60 minutes. 



3. To clear, put the dehydrated tissue into 6 or 8 times its 

 volume of cedar oil-xylol (I, E, p. 15). Pieces of 4 or 5 mm. 



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