THE COLON-TYPHOID GROUP 143 



Differences are also noted in the growth on special media, 

 such as those of Hiss and Eisner. On Eisner's potato-gelatin 

 the colon bacillus and the typhoid bacillus both grow read- 

 ily. The medium of Hiss is of some assistance in isolating 

 the germ. (See p. 75.) 



Hiss Media. Shows B. coli, large colony, even borders. 

 B. typhi, small colony, hairy and fringy threads. (See p. 75.) 



Endo-fuchsin-lactose A gar (see p. 77). Incubation on 

 plates of this media shows B. coli red; typhoid as clear, color- 

 less drops. 



Malachite green added to agar permits the growth of B. 

 typhi, but not B. coli. The dye must be as nearly neutral as 

 possible. 



Bile Salt Media. Fresh bile or sodium taurocholate added 

 to lactose glucose agar or broth permits the rapid growth of 

 both B. typhi and B. coli, fermentation with gas formation 

 denoting B. coli, growth without fermentation meaning 

 typhoid. 



Drigalski and Conradi Media. Petri plates filled with 

 this media are inoculated on the surface only. Placed in 

 incubator sixteen to twenty-four hours. Typhoid colonies 

 small, transparent, and blue. Colon colonies red, coarser, 

 and larger. 



Typhoid Bacilli from Blood. Conradi, Busquet, Coleman 

 and Buxton, and others have found the bacilli in the blood of 

 every patient by the following method: A mixture of ox-bile, 

 90 c.c., glycerin, 10 c.c., and peptone, 2 gm., is distributed 

 into 20 c.c. flasks and sterilized. Ten cubic centimeters of 

 blood is drawn from the elbow into a glass syringe and divided 

 among three flasks. These are incubated, and in twenty-four 

 hours litmus-lactose- agar plates are inoculated on the surface 

 by a stroke from the flasks. A growth is obtained in five or 

 six hours. 



If the growth is a bacillus which has not reddened the 

 medium, it is tested for the Widal reaction with immune se- 

 rum. The diagnosis has been made as early as the second day. 



Paracolon or paratyphoid bacilli are members of the 



