STAINING OF BACTERIA 35 



XV. Capsule Stain of Hiss. 



Use the following, heated until it steams: 



Saturated alcoholic solution of gentian- 

 violet or fuchsin 5 c.c. 



Distilled water 95 c.c. 



Wash in 20 per cent, solution of cupric sulphate crystals. 



XVI. Capsule Stain of Welch. 



(i) Pour glacial acetic acid on film. After a few seconds 

 replace with anilin-water gentian-violet without washing in 

 water. (2) Remove all acid by several additions of stain, and 

 allow it to act for three to four minutes. (3) Wash and examine 

 in salt solution 0.8-2.0 per cent. 



XVII. Romanowsky Stains. 



A compound dye originally used for malarial parasites, but 

 now employed in some of its modifications in staining blood- 

 films, bacteria in tissues, and protozoa generally. 



The stain is difficult to prepare, and can be purchased of 

 supply houses to better advantage. 



The chief modifications are: 



Leishman's stain, consisting of a i per cent, solution methyl- 

 ene-blue, to which 0.5 per cent, sodium carbonate has been 

 added and allowed to stand for twelve hours in incubator at 

 65 C., and then ten days at room temperature, and a solution 

 of eosin (i : 1000) in water. Equal parts of these solutions 

 are mixed and allowed to stand for six hours. After it has 

 been washed and dried, the precipitate is dissolved in methyl- 

 alcohol. 



Giemsa stain: 



Azur II. eosin 3 parts. 



Azur II 8 



Glycerin (pure) 250 " 



Methyl-alcohol '. 250 " M. 



Azur is a mixture of methylene-blue and eosin prepared in a 

 special way. 



