41 



TABLE XVIII. (a) SHOWING CORRELATION OF CHARACTERS AMONG 89 

 SUCROSE NEGATIVE STRAINS OF THE COLI SECTION. 



TABLE XVIII. (b) COEFFICIENTS OF CORRELATION FOR EACH PAIR OF 

 CHARACTERS IN TABLE XVIII. (a). 



dulcitol, and indol, showing coefficients of +0.86, +0.78, and +1.0 re- 

 spectively. Subdivision is therefore made upon salicin. 



For each of the resulting subgroups new correlation tables are made 

 and further subdivision again carried out on the best correlated char- 

 acter. A point is very quickly reached where further subdivision, upon 

 correlated characters, is no longer feasible. These groups are regarded 

 as species and to each was assigned, as far as possible, the name of the 

 MacConkey variety which it most resembled. 



Levine's Classification. The following classification is suggested 

 by the author, based upon a study of 333 strains obtained from soil, 

 sewage, and the feces of man, horse, sheep, pig, and cow. 



The characters employed are the methyl-red and Voges-Proskauer re- 

 actions, indol production, motility, gelatin liquefaction and gas formation 

 from sucrose, raffinose, dulcitol, glycerol, salicin, dextrin, inulin and corn 



