QUALITATIVE BACTERIOLOGICAL ANALYSIS. 91 



Gilbert and Lion investigated the varieties of B. coli found 

 in the stools of sixty healthy men ; they divided the bacilli into 

 the following groups : 



A. Motile bacilli : 



(a) Very motile cultural reactions ; milk coagulated, milk- 

 sugar fermented, indol reaction sometimes present. 



(b) Slightly motile cultural reactions : (a) milk coagu- 

 lated, milk sugar fermented, indol reaction sometimes 

 present ; (/3) milk sugar not fermented, milk not coagu- 

 lated, indol reaction present. 



B. Non-motile bacilli : 



(a) Milk sugar fermented, milk coagulated. 



Sub-variety : (a) colonies thick and opaque, indol 



sometimes present. 

 Sub-variety : (/3) colonies thin and transparent, indol 



sometimes present. 



(b) Milk sugar not fermented, milk not coagulated, no 

 indol produced. 



Gordon has made a careful study of the varieties of B. coli ; 

 he investigated over one hundred organisms, and classified 

 them according to (1) their reactions, and (2) their flagella 

 averages, and in this way differentia ted sixteen varieties. Two 

 other groups of organisms were also investigated, which 

 resembled B. coli in morphology; but the members of the 

 first group produced alkali in litmus-tinted media, and the 

 members of the second group slowly liquefied gelatine. The 

 following table taken from Gordon's paper in the Journal of 

 Pathology and Bacteriology gives the reactions of the different 

 varieties of B. coli : 



