MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



3. Stain with Solution B for five minutes, heating till steam 

 rises ; or stain at room temperature overnight. 



4. Decolorize for twenty seconds in acid alcohol; then wash 

 thoroughly in water to which two or three drops of ammonia have 

 been added to remove the acid. 



5. Differentiate in 95% alcohol. 



6. Dehydrate; clear and mount. 



If Celloidin or L.V.N, sections are employed, clear in terpineol 

 or origanum oil ; blot carefully on slide and mount. 



Results: 



Tubercle bacilli, bright red. Nuclei, blue. 



CARBOL FUCHSESr - HAEMATOXYLIN - PICRO 



ACID FUCHSIN 



For M. leprae in sections 



Solutions required: 



A. Carbol fuchsin (Ziehl Neelsen). 



B. Hydrochloric acid, cone. . . 3 ml. 

 Absolute alcohol . . • • 97 rnl* 



C. Potassium permanganate 1% aqueous. 



D. Oxalic acid 2% aqueous. 



E. Haematoxylin (Ehrlich). 



F. Picric acid, saturated, aqueous . . 50 ml. 

 Acid fuchsin, aqueous 1% . . 10 ml. 

 Distilled water . . . . 40 ml. 



Technique: 



1 . Pieces of tissue are fixed for three to seven days in a mixture 

 consisting of equal volumes of 10% formalin and absolute alcohol, 

 and parafHn sections are employed. 



2. Stain sections in the carbol fuchsin solution in a stoppered 

 staining jar for three or four days. 



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