BACILLUS-COLI-LlKE BACTERIA FROM FECES AND SEWAGE 



17 



the horse strains is due to the influence of these few cultures and is 

 not a characteristic of horse strains in general. 



The high average, 1.18% normal acid, of the 17 sewage strains 

 which attacked sucrose, is due entirely to the presence among them 

 of 9 Voges-Proskauer-positive organisms. The mean for the other 

 8- sewage strains is 0.75% normal acid. 



Voges-Proskauer-negative strains attack sucrose less readily than 

 the Voges-Proskauer-positive strains. The means for the two groups 

 are 0.74 and 1.57%, and the empirical modes 0.7 and 1.5% normal acid 

 respectively. 



B. RAFFINOSE 



The frequency distributions of the organisms with respect to acid- 

 production in raffinose and the relation of acid-formation to the Mac- 

 Conkey types, to the source, and to the Voges-Proskauer reaction, are 

 given in Table 7. 



TABLE 7 



RELATION OF SOURCE, MACCONKEY TYPE, AND VOGES-PROSKAUER REACTION TO ACID-PRODUCTION 



IN RAFFINOSE 



All the strains considered, somewhat more acid is formed from 

 raffinose (1% normal) than from sucrose (0.7%). No distinct mode 



