SYSTEMATIC AND DESCRIPTIVE. 257 



METHODS OF STAINING THE COMMA-BACILLI 



OF KOCH. 



In cover-glass preparations they may be well stained in 

 the ordinary way with an aqueous solution of methyl violet 

 or fuchsine, or by the rapid method, without passing through 

 the flame (p. 50, Babes' method). 

 Nicati and Rietsctis method* 



A small quantity of the stools or of the scraping of the 



intestinal mucous membrane is spread out on a glass 



slide and dried, then steeped during some seconds 



in sublimate solution or in osmic acid (i 100). It 



is then stained by immersion in fuchsine-aniline 



solution (i or 2 grammes of Bale fuchsine dissolved 



in a saturated aqueous solution of aniline, washed, 



dried, and mounted in Canada balsam. 



In sections of the intestine their presence may be 



demonstrated by 



(a) Koch's method.} 



Sections of the intestine, which must be well hardened 

 in absolute alcohol, are left for twenty-four hours in 

 a strong watery solution of methylene blue, or for a 

 shorter time if the colour solution is warmed. Then 

 treated in the usual way. 



(b) Babes' method. % 



Sections, preferably from a recent case of cholera, and 

 made as soon as possible after death, are left for 

 twenty-four hours in a watery solution of fuchsine 

 (fabrique de Bale), then washed in distilled water 

 faintly acidulated with acetic acid, or in sublimate 

 solution (i 1000), passed rapidly through alcohol 

 and oil of cloves, dried with filter paper, and pre- 

 served in Canada balsam. 



* Brit. Med. Journal, Sept. 1885. 



t Berliner Klinische Woch., No. 31. 



\ Cornil and Babes, Les Bacteries, p. 458, 1885. 



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