214 Theobald Smith 



The Bacillus- Cloaca Type of Gas Production. — The tj^pes of 

 gas production hitherto described present certain underlying 

 characters which suggest a close relationship. These I group 

 together as the B. coli type since it differs quite markedly 

 from the type now to be described. 



The species known as B. f/^ar,^ was first described by E. O. 

 Jordan^* as coming from sewage. The cultures which I have 

 ranged under this name have been obtained, with one exception, 

 from water both polluted and unpolluted. The exception was 

 reputed to have come from cornstalks. It is therefore a widely 

 diffused organism whose true habitat I do not know, although 

 I am strongly of the opinion that it is an organism living on 

 decaying vegetable matter. If so, its name is unfortunate as 

 it could not be regarded as a sewage bacterium .strictly speak- 

 ing. It is a small bacillus closely resembling B. coli in form 

 and size and is actively motile. On gelatin the surface colo- 

 nies appear at first as thin expansions with slightly irregular 

 outline. Two or three days after the colonies have appeared, 

 liquefaction sets in. This peculiar retardation of liquefaction 

 is noteworthy and in general, it may be said, that the rapidity 

 varies slightly from culture to culture and is gradually weak- 

 ened during artificial cultivation. Milk I find coagulated 

 only after seven or eight days. On potato a fleshy, pale yel- 

 lowish, not characteristic growth appears after one or more 

 days. I may state here that two varieties of this species have 

 come under my observation which I designate provisionally 

 a and /?. For a, the bouillon becomes uniforml}^ turbid, for /3 

 very feebly so with a tendency of the growth to form flakes 

 somewhat like the flocculi of anthrax cultures. Evidenth- 

 there is in /3 a greater tendency towards cohesion of the 

 bacilli. 



The gas production of B. cloaccs is very rapid in glucose and 

 saccharose bouillon and slow in lactose bouillon. 



