SECTION ONE 



Technique: 



Fix in the warm acid for a maximum period of fifteen minutes; 

 then remove excess acid by washing in 30-50% alcohol. 



Remarks: 



Acetic acid glacial is rarely used alone : it causes the swelling of 

 cell constituents, etc., and it is of most value when mixed with such 

 substances as formalin, alcohol, mercuric chloride, etc., to counter- 

 act their shrinking effect. 



Acetone 



Recommended for : 



Rapid fixation of brain tissue for rabies diagnosis. (R. D. Lillie, 

 Histopathologic Technique.) It is also employed for fixing tissue 

 enzymes, particularly phosphatases and lipases. 



Technique: 



Thin slices of tissue are fixed in pure acetone for twelve to 

 twenty-four hours at 0° C. ; they are then dehydrated by immer- 

 sion in two changes of pure acetone for two hours in each at room 

 temperature, and afterwards cleared by immersing for half an hour 

 in each of two changes of benzene before infiltration with paraffin 

 wax.* 



Alcohol Absolute 



Recommended for : 



Glycogen, Amyloid, Fibrin, Hyaline, Haeipofuscin, Phos- 

 phatase. 



Technique: 



Fix from two hours to several days according to the nature of 

 the material; dehydrate; clear. 



Remarks: 



Unsuitable for fats and lipines as these are dissolved by the 

 higher concentrations of alcohol. 



*Gomori, Proc. Soc. Exp. Biol, and Med., 58, 362, 1945. 



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