102 ST?JE\ OF BACTERIA 



Charge the stain four or five times to remove the acid. Stain four 

 minutes, and wash with 2 percent NaCl solution, not water. This 

 demonstrates the capsule very well. 



His's Method. 



"A." 



1. Make cover-glass preparation mixing specimen with blood serum. 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." 



. 2. Dry and fix. 



3. Heat and pour on the following stain, steaming thirty seconds: 



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



(b) Water 95 c.c. 



4. Wash in a 20 percent solution cupric sulphate. 



5. 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 percent 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 brifliantjred, while_the body of the bacilli 

 are stained blue. 



Flagella Staining 



To a beginner flagella staining is difficult; there have been many 

 well-known methods devised. The simpler are as effective as the 

 more complicated but do not always make as pretty preparations. 



