CHARACTERISTICS OF THE COLON-AEROGENES GROUP 89 



salicin is slightty higher for the high ratio group. Only a 

 very few cultures of either group are able to utilize inulin. 



These results agree in a general way with those reported 

 by Burton and Rettger 17 and Johnson and Levine, 18 except 

 that the latter found a higher percentage of glycerol fer- 

 menters among the Voges-Proskauer plus cultures. They give 

 no data for mannitol. In summarizing these observations we 

 may say that the greater fermentative ability of the high 

 ratio group is shown in the volume of the gas formed, the 

 extent of the decomposition usually effected, and in the range 

 of material available for fermentation. While the correla- 

 tions are not perfect, they indicate an additional real differ- 

 ence between the two groups. 



Subdivision of the low ratio or B. coli group. It has been 

 customary to divide B. coli into two varieties designated as 

 communis and communior on the basis of the fermentation of 

 saccharose. This classification has been partially followed by 

 Kligler, 1<J but Levine 20 has made of this V and P- group 

 six species, including one which is still further subdivided into 

 two varieties. A major division is made on the ability to 

 ferment saccharose, and the specific and varietal distinctions 

 on motility and the fermentation of saliein correlated with 

 dulcitol and glycerol. Burton and Rettger 21 suggest three 

 species of which one liquefies gelatin and two, designated as 

 communior and communis, are distinguished by the saccha- 

 rose fermentation. 



The data on which Levine 's separation is based are not given 

 and, as we did not include motility in our observations, we 

 are unable to apply his classification to our cultures. Without 

 admitting the validity of basing specific differences on the 

 fermentation of a single sugar we have separated the low 

 ratio cultures in the usual way as shown in Table III and 

 Fig. 3. The low ratio liquefiers, which probably agreed with 



17 Loc. cit. 



18 Loc. cit. 



10 I. J. Kliger, Studies on the Classification of the Colon Group in Jour. 

 Inf. Dis., 15, 1, pp. 187-204, 1914. 



20 Loc. cit. 



21 Loc. cit. 



