272 



MAX LEVINE 



and glycerol shows a strong negative association. Those strains 

 which failed to attack glycerol practically always fermented 

 dulcitol. Thus 26 of 27 glycerol negative are dulcitol positive 

 while 17 of 18 dulcitol non-fermenters, tested, formed gas from 

 glycerol. To put it another way, inability to attack either of 

 the alcohols is accompanied by fermentation of the other. Fer- 

 mentation of either, however, yields but little information as to 



TABLE 9 

 Showing correlation of characters among 16 sucrose positive, non-motile strains, of 



the coli group 



TABLE 9a 

 Coefficients of correlation for each pair of characters in table 9 



how the other will react. The desirability of subdividing on 

 either glycerol or dulcitol to form two species is questioned. For 

 the present the entire group of sucrose fermenting motile forms is 

 designated as B. communior and two varieties may be formed on 

 glycerol or dulcitol. 



The sucrose-positive non-motile subgroup. Only 16 of the 

 sucrose fermenters were non-motile, and only one of these failed 

 to produce indol. Although the number of organisms is small, it 

 is quite surprising that they should be so evenly divided with 

 respect to gas formation from the test substances. Thus 6 



