MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



MACCHIAVELLO'S STAIN 

 For Rickettsiae 



Solutions required: 



A. Basic fuchsin . . . . . . 0.25 gm. 



Distilled water adjusted to pH 7-2- 



7*4 with alkali . . . . . . 100 ml. 



This solution should he freshly prepared and 

 filtered. 



B. Citric acid 0-5% aqueous. 



C. Methylene blue 1% aqueous. 



Technique: 



1. Spread smears of the infected tissue on scrupulously clean . 

 slides. ' I 



2. Fix by flaming gently. 



3. Stain for four minutes with solution A. 



4. Pour off the excess stain; then wash to preparation rapidly 

 with the citric acid solution. 



5. Wash with tap water. 



6. Stain for a few seconds with the methylene blue. j 



7. Wash; dry; examine. 



Results: 



Rickettsiae, red. Tissue cells, blue. 



MALACHITE GREEN 

 A simple method of staining spores 



Solutions required: 



A. Malachite Green 5% aqueous. 



B. Safranin 0-5% aqueous. 



Technique: 



I. Bacterial films are dried by heating gently over a bunsen 

 flame. 



380 



I 



