MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



Pour the alcohol and ether into a clean, absolutely 

 dry, wide-mouth bottle of about 32 ounce capacity, 

 and mix by inverting the bottle several times, re- 

 leasing the stopper at intervals, to release the pressure 

 of ether vapour; then add the Celloidin flakes and 

 invert the bottle as before. Leave for about 12 hours 

 to dissolve ; inverting or shaking the bottle gently at 

 intervals. 



B. Celloidin 4% 



Celloidin solution 8% . . . . 2 volumes 

 Absolute alcohol . . . . . . i volume 



Ether i volume 



Mix as described above, in a large-stoppered wide- 

 mouth bottle. 



C. Celloidin 2% 



Celloidin 4% 

 Absolute alcohol . . 

 Ether 



D. Cedarwood oil, for clearing 

 Chloroform 



2 volumes 

 I volume 

 I volume 



I volume 

 I volume 



Technique: 



(a) Wet Method 



1. Pieces of tissue not thicker than 5 mm. are fixed in the usual 

 manner. 



2. Wash in running water for the prescribed time for the parti- 

 cular fixative. If a fixative containing mercury has been used, 

 remove mercurial precipitate by the standard technique. 



3. Immerse the pieces of tissue for two hours in each of the 

 following: 50%, 70% and 90% alcohol. 



4. Immerse in absolute alcohol from two to sixteen hours, 

 according to the nature and thickness of the tissue. 



5. Immerse for twenty-four hours in a mixture consisting of 

 equal volumes of absolute alcohol and ether, in a stoppered wide- 

 mouth bottle, which must be absolutely dry. 



6. Impregnate with 2% Celloidin solution from five to seven 



days. 



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