BACILLUS-COLI-LlKE BACTERIA FROM FECES AND SEWAGE 



11 



sheep strains is the lowest, 1.21%, as compared with 1.34% for human 

 strains, 1.38% for horse, 1.36% for sewage, 1.31% for cow, and 1.28% 

 normal for pig strains. The lower average of the sheep strains is due 

 to the presence among them of a few low-acid-producing organisms 

 rather than to a lesser ability of the group as a whole to attack manni- 

 tol. That sheep strains form acid from mannitol as readily as do those 

 from the cow, pig, and man is indicated by the coincidence of their 



TABLE 3 



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



IN MANNITOL 



modes. The strains from the horse tend to form somewhat more 

 acid than do those from other animals, but the difference is too slight 

 to be of any differential significance. 



D. LACTOSE 



The amount of acid formed from the disaccharid, lactose, in 1 % 

 lactose peptone solution is very nearly the same as that formed from 

 the monosaccharid, galactose, and from the hexite, mannitol. The 

 mode for all strains is at 1.30%, and the mean is also at 1.30% normal 

 acid. The frequency distributions are shown in Table 4. 



