BACILLUS COLI 65 



whether in plates or as a streak culture, the growth 

 of B. Coli closely resembles that of B. Typhosus, 

 but is somewhat more rapid and shows an even 

 greater tendency to form a filmy spreading growth 

 (Fig. 60). 



B. Coli possesses the power of fermenting sugars 

 of both the C 6 H 12 O 6 and C 12 H 22 O n groups, and as 

 a consequence coagulates milk and produces gas in 

 fluid or solid media containing these sugars. A 

 gelatine glucose tube inoculated in stab is rapidly 

 dislocated by the gas bubbles, and presents the 

 appearance shown in Fig. 61. B. Typhosus, under 

 the same conditions, produces no gas and no coagu- 

 lation of milk, and the two organisms are further 

 distinguished by the property possessed by B. Coli 

 of producing indol in solutions of peptone and the 

 absence of this power in the case of B. Typhosus. 



