STAINING, PRACTICAL AND THEORETICAL 



Remarks: 



Unsuitable for fats and lipines as these are dissolved by the 

 higher concentrations of alcohol. 



Allen's Fixative (B.15) 



Recommended for : 

 Chromosomes. 



Recipe: 



Technique: 



Fix tissues from four to sixteen hours then immerse in frequent 

 changes of 70% alcohol over a period of forty-eight hours or until 

 the yellow coloration due to picric acid ceases to come out. 



Remarks: 



The solution deteriorates very rapidly and it is, therefore, essen- 

 tial that this fixative should be prepared only when it is required 

 for immediate use. 



Bouin's Fluid 



Recommended for : 



Embryological specimens, for elementary bodies, Purkinje cells, 

 Argentaffin reaction, and for animal tissues in general. 



Recipe : 



Picric acid, saturated aqueous . . 75 ml. 



Formalin . . . . . . • • 25 ml. 



Glacial acetic acid . . . . • • 5 ml. 



Technique: 



Fix from eighteen hours to two days; then wash in 50% fol- 

 lowed by 70% alcohol until most of the yellow coloration, due to 



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