SECTION SEVEN 



2. Heat on a steam bath till water condenses in droplets on the 

 bottom of the slides. 



3. Flood films with Solution A and heat for one minute; then 

 pour off excess stain and wash well with water. 



4. Counterstain thirty seconds in Solution B; then wash with 

 water; blot dry and examine. 



Results: 



Spores, green. Vegetative forms, red. 



MALACHITE GREEN - BASIC FUCHSIN 

 For staining yeasts or bacteria 



Solutions required: 



A. Basic fuchsin 10% alcoholic . . 0-5 ml. 



Malachite green 0-5% aqueous . . 100 ml. 



Technique: 



1. Spread smears on slides with a platinum wire loop in the 

 usual manner. 



2. Place slides, smear facing upwards, on the corner of a tripod. 



3. Flood slide with the staining solution. 



4. Heat the underside of the slide very gently over a small 

 bunsen flame some distance away from the slide until steam rises. 



5. Pour off excess stain after a minute or so. 



6. Wash well with distilled water. 



7. Drain; blot dry, and examine. 



Results: 



Spores are stained greenish blue, while vegetative forms appear 

 violet to pink. 



Reference: Gray, P. H. H. (1941), Nature, 147, 329. 



MALACHITE GREEN - PYRONIN - CRYSTAL VIOLET 



(Sandiford) 



A contrast stain for gonococci and meningococci being a 

 Gram stain with modified Pappenheim as counterstain 



381 



