90 STUDY OF BACTERIA 



2. Without washing off the acid, aniline water gentian violet is poured on. 

 Change the stain four or five times to remove the acid. Stain four minutes. 

 This demonstrates the capsule very well. 



His's Method. 



"A". 



1. Make cover-glass preparation as usual. Fix in flame. 



2. Stain for a few seconds with a half concentrated water solution of gentian 

 violet. 



3. Wash in weak potassium carbonate solution for a few minutes. 



4. Dry and mount. 



"B". 



1. Dry and fix. 



2. Heat and pour on the folio whig stain: 



a. Saturated alcoholic solution of gentian violet 5 c.c. 



b. Water 95 c.c. 



3. Wash in a 20 percent solution cupric sulphate. 



4. Dry and mount. 



Spore Staining. 



Spores resist stains, and when stained are hard to decolorize. 



1. Dry and fix in the usual way. 



2. Flood cover-glass with hot carbol-fuchsin; heat until it steams; repeat 

 this once or twice. This stains bacteria and spores. 



3. Wash in water. 



4. Decolorize with 



Alcohol 2 parts. 



i % acetic acid i part. 



5. Wash. 



6. Counterstain with methylene blue. 



7. Wash, dry and mount. 



By this method, which is a simple and satisfactory one, the spores 

 are stained a brilliant red, while the body of the bacilli are stained 

 blue. 



