CHARACTERISTICS OF THE COLON-AEROGENES GROUP 89 
salicin is slightly 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’*” and Johnson and Levine,™ 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,+® but Levine *° 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 salicin correlated with 
dulcitol and glycerol. Burton and Rettger™* 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 
1 Loc. cit. 
18 Loc. cit. 
27, J. Kliger, Studies on the Classification of the Colon Group in Jour. 
Inf. Dis., 15, 1, pp. 187-204, 1914. 
2° Loe. cit. 
21 Loe. cit. 
