SECTION THRKE 



Formalin Buffered 



Recipe : 



Neutral formalin, as above . . . . i litre 



Sodium dihydrogen phosphate, mono- 

 hydrate, A.R. . . . . -4 gm. 

 Disodium phosphate anhydrous, A.R. 6-5 gm. 



Technique: 

 As for neutral formalin. 



Remarks: 



Neutral formalin turns acid on keeping owing to the production 

 of formic acid, whereas the buffered fixative remains neutral. 



Recommended for : 



All purposes for which neutral formalin is employed where a 

 neutral fixative is required. 



Formol - Alcohol 



Recommended for : 



Glycogen in animal tissues. Fibrin. Peroxidase. Plant tissues, 

 particularly pollen tubes in styles. 



Recipe: 



Formalin (40% formaldehyde) . . 100 ml. 

 Alcohol 70% . . . . . . . . 900 ml. 



Technique: 



Fix for three to six hours; then dehydrate, clear and embed. 

 Alternatively, if it is not convenient to dehydrate, clear and embed 

 at once, the tissues may be stored for long periods without 

 deleterious effects in 70% alcohol. 



Remarks: 



This fixative, which penetrates quickly, while compatible with 

 most stains, is particularly suitable for indigo carmine. 



Kelly's Fluid 



Recommended for : 



Animal tissues in general, but particularly for blood-forming 

 organs. 



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