SECTION SEVEN 



CARBOL FUCHSIN - BORREL BLUE 

 For leprosy and for tubercle bacilli 



Solutions required: 



A. Carbol fuchsin (Ziehl Neelsen). 



B. Sulphuric acid 5%. 



C. Hydrochloric acid . . . . i ml. 

 Alcohol 70% . . . . . • 99 nil- 



D. Borrel Blue . . . . • • 5 ml. 

 Distilled water . . . . . . 20 ml. 



Technique: 



1. Air-dried smears are fixed in absolute alcohol for three min- 

 utes. 



2. Place the preparation on the corner of a tripod; flood with 

 carbol fuchsin ; then heat gently with a small bunsen flame until 

 steam rises. 



3. Allow the stain to act for five minutes. 



4. Decolorize with 5% sulphuric acid until only a faint pink 

 colour comes away. 



5. Wash in 60% alcohol until no more stain comes out. 



6. Rinse in distilled water. 



7. Counterstain in the diluted Borrel Blue for one half to one 

 minute. 



8. Pour off excess stain; rinse with distilled water; drain and 

 blot dry. 



Results: 



Bacillus leprae and tubercle bacilli bright red. Other bacteria 

 are stained blue, while cells, cell debris and mucin in sputum are 

 in varying shades of blue. 



Note: In the case of leprosy, differentiation of the carbol fuch- 

 sin (Stages 4 and 5) must be very carefully carried out, as this 

 organism is more easily completely decolorized than tubercle 

 bacilli. 



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