MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



5. Rinse with distilled water. 



6. Drain; dry thoroughly but carefully. 



7. If it is desired to preserve the preparation, mount at once in 

 Cristalite. 



Results: 



Treponema pallidum^ light reddish brown. Mouth spiro- 

 chaetes and Treponema refringens, deep reddish brown. 



CARBOL FUCHSIN 

 For acid-fast bacteria, in sputum, including tubercle bacilli 



Solutions required: 



A. Ziehl Neelsen carbol fuchsin. 



B. Acid alcohol: 



Alcohol 95% . . . . • • 97 nil. 



Cone. Hydrochloric acid . . 3 ml. 



C. Loeffler Methylene Blue. 



Technique: 



1 . Sputum smears are fixed on a flat surface over boiling water. 



2. Stain with Solution A for three to five minutes, heating the 

 slide till steam rises. 



3. Pour off excess and allow the slide to cool somewhat before 

 rinsing in water. 



4. Decolorize in Solution B until only a faint pink colour comes 

 away ; then wash with water. 



5. Counterstain with Solution C for ten to thirty seconds; then 

 wash in water ; dry and examine. 



Results: 



Acid-fast bacteria, red. Other organisms, blue. Background, 

 faint blue or colourless. 



354 



