CHARACTERISTICS OF THE COLON-AEROGENES GROUP 91 



a fundamental difference, especially if it is not correlated 

 with other reactions. So far as data are available, the low 

 ratio or />. coli group appears to be a very definite and cir- 

 cumscribed entity and there is no apparent reason for 

 separating it into species. Varieties on the basis of saccha- 

 rose fermentation might be recognized but the need for these 

 is not very evident. 



Gdotin- --=1.06 Vand R- - 



Saccharose + Saccharose 



100 8O 6O 40 20 + 1 - 20 40 60 80 100 100 80 60 4O ZO + 1 - 20 40 60 80 fOO 



Fig. 3 



Subdivisions of the high ratio group. The high ratio or 

 aerogenes type shows more evidence of being a heterogeneous 

 group capable of subdivision into species than the group just 

 considered. Johnson and Levine, 22 following the earlier sug- 

 gestions of Levine, 2 " have two species, in one of which all 

 cultures are motile and nearly all liquefy gelatin while in 

 the other all are immotile and nearly all fail to liquefy gelatin. 

 They have also a V and P group which otherwise resembles 

 the aerogenes type and which they consider as intermediate 

 between coli and aerogenes. Burton and Rettger 24 have three 

 groups, one of which is a liquefying spore former, one a non- 

 spore forming gelatin liquefier of the cloacae type and one a 

 non-liquefier of the aerogenes type. In our collection from 

 grains we found evidences of four high ratio groups including 

 one of 40 liquefying cultures and one of 90 non-liqueners with 



- J Loc. cit. 



23 LOG. cit. 



24 Loc. cit. 



