52 BACTERIOLOGY? 



Staining of Capsules. — The capsules which many bacteria 

 possess, appear to be made of some gelatinous substance, which 

 is difficult to stain. 



Method of Hiss.' — (a) Cover-glass preparations are made ip 

 the ordinary way and fixed in the flame as soon as dry. 



(b) Use the following stain, heated till it steams: 



Saturated alcoholic solution of gentian violet or fuchsin 5 c.c. 



Distilled water 95 c.c. 



(c) Wash in 20 per cent solution of cupric sulphate crystals. 



(d) Dry and mount in Canada balsam. 



The method of Hiss is recommended to be used for bacteria that 

 have been cultivated on serum-agar with i per cent of dextrose. 

 This method gives excellent results with preparations of capsulated 

 bacteria in smears of animal tissues. 



Method of Huntoon^ — In this method two solutions are re- 

 quired. 



Solution I. — Sift 3 grams nutrose into 100 c.c. distilled water 

 and steam for one hour. Then add 5 c.c. of 2 per cent, aqueous 

 solution of carbolic acid. Allow the sediment to settle and employ 

 the supernatant liquid as the diluent. 



Solution 2. — Mix the following, 100 c.c. of 2 per cent aqueous 

 carbolic acid; 0.25 to 0.50 c.c. of concentrated lactic acid; i c.c. 

 of I per cent acetic acid; i c.c. of saturated alcohohc fuchsin; 

 and I c.c. of old carbol-fuchsin solution. 



Solution I is placed on the slide and the bacteria are emulsified 

 in it and then spread with the platinum loop. When dry the film 

 is covered at once with solution 2 for thirty to fifty seconds. Wash 

 quickly in water, dry and examine. 



Staining of Flagella.— Flagella are among the most difficult 

 of all objects to stain. The best-known method is that of Loffler. 

 It is important to use young cultures (4 to 10 hours old), preferably 

 on agar. 



(a) A small amount of the growth is gently mixed with a 



^ Huntoon, Journal of Bacteriology, May, 191 7, Vol. 11, p. 241. 



