318 



L. A. EOGERS 



Browne used the MacConkey-Jackson system of classification 

 which is merely the possible arrangements of plus and minus 

 signs under sucrose and dulcite and has no relation to the 

 varieties arranged by nature. 



CULTURES HELD IN WATER IN PERMEABLE SACS 



Conditions more nearly approximating those found when 

 sewage is emptied into streams were obtained by holding cul- 

 tures or fecal matter in parchment sacs suspended in running 

 water. This was repeated several times both in the laboratory 

 and in small streams, but nearly every experiment came to an 

 untimely end through overheating, freshets or other causes before 

 very complete results were obtained. 



In all cases in which the temperature of the water was rela- 

 tively high there was an increase in the colon bacteria of both 

 types. 



Table 2 shows the results obtained by holding a small amount 

 of dilute sewage in a parchment sac in running water. The sac 

 was made by folding parchment paper around a bottle from 

 which the bottom had been removed. This bottle properly 

 protected, was held in running tap water at a temperature of 

 16 to 20.6° C. 



There was no increase in numbers observed but otherwise 

 these results agreed with those obtained on other sacs under 

 similar conditions. The total number decreased far more rapidly 

 than was the case in the bottle held in the incubator at 20° and 



