90 



UNIVERSITY OP WISCONSIN STUDIES 



Burton and Rettger's group IV included only three cultures 

 and are omitted. There is 110 difference in the proportion of 

 cultures forming indol in the two groups. Raffinose is fer- 

 mented by nearly all of the cultures fermenting saccharose and 

 is fermented by only a very few of the cultures which do not 

 ferment saccharose, but considering the chemical relation of 

 these two sugars, this high correlation becomes of minor 

 significance. The percentage of cultures fermenting glycerol 

 and salicin is slightly higher in the saccharose group but the 

 difference is so slight that it has no significance. On the whole, 

 these data furnish no sound basis for separating the low 

 ratio group into species. 



TABLE III 

 CHARACTERISTICS OP LOW RATIO, GELATIN NEGATIVE CULTURES 



The idea of making species or even varieties on a single 

 fermentation seems to us a very questionable one. A fer- 

 mented sugar is merely a source of carbon and, while the" fer- 

 mentation may be a constant reaction, it does not represent 



