COLON-AEROGENES FORMS FROM NATURAL WATERS 



59 



The second series represents strains which passed through 

 enrichment processes whenever they showed delayed reaction 

 with media. Perhaps this may have somewhat diminished the 

 number of forms varying about the three types. In the course 

 of this treatment the purity of our strains was assured. ' 



There are differences in reactions of strains from a single source 

 or from one sample of water. Nine of the samples were from 

 75-foot tubular wells in the same stratmn : two were from a group 

 of wells furnishing a city supply, and the remaining seven were 

 from a single nearby well. Table 2 shows the numbers of strains 



TABLE 2 

 Strains isolated from one source 



assigned to each provisional group. As many as 7 strains, dis- 

 tributed among 6 groups, were found in a single sample. Of the 

 44 strains assigned to 9 groups, 22 are uric acid positive; 14 uric 

 acid positive, adonitol positive; and 14 fall into the transition 

 groups 5, 9, 10, and 11. Eight vary about ''non-fecal," and 14 

 about ''fecal aerogenes;" 19 about the Bad. coli type, and 3 give 

 slow lactose fermentation. Other instances of varying strains 

 from a single sample can be found in table 3. 



SPECIAL STUDY OF STRAINS IN TRANSITION GROUPS 



Thirty-five strains, mostly from the second series, were tested 

 with a number of sugars, alcohols, etc. (In these tests both a 



