STAINING, PRACTICAL AND THEORETICAL 



5. Counterstain in Solution B for one minute. 



6. Wash quickly in tap water ; transfer sections to slides ; drain 

 and mount in glycerine jelly, or Aquamount. 



Results: 



Fat globules : black or greyish black against a red background. 

 Caution : Osmic acid vapour is injurious to the eyes. 



OSMIC ACID - ALPHANAPHTHYLAMINE - ALCIAN BLUE 



For the simultaneous demonstration of normal and 

 degenerating myelin 



Technique: 



1. Cut frozen sections of unfixed tissue, on a cryostat, at 5jLt; or 

 cut formalin-fixed tissue, on the freezing microtome, at 10 to i5ju. 



2. Immerse the sections for eighteen hours in solution D. 

 Note: The vessel into which the sections are to be placed 



should be tightly stoppered to prevent volatilization of osmium 

 tetroxide. 



3. Wash the sections in distilled water for thirty minutes. 



4. Immerse sections in the a-naphthylamine (solution E) in 

 the incubator at 37° C; i5ju, sections for ten to fifteen minutes; 

 5ft sections for twenty minutes. 



Note: The a-naphthylamine solution should be warmed to about 

 37° C. before the sections are placed in it. 



338 



