DETERMINATION OF ORGANISMS 



73 



COMPARATIVE EFFECTS OF CHLORINE DISINFECTION 

 UPON 20 AND 37 COUNTS, SWIMMING POOL WATER 

 AT UNIVERSITY OF WISCONSIN 



(TULLY, 1912) 



Under ordinary conditions it is clear that organisms 

 growing at the body temperature and those fermenting 

 lactose are not numerous in normal waters. The 

 absolute count at 37 seldom exceeds 50, and is rarely 

 over 10 per cent of the 20 count, except after hot 

 periods in the late summer ; acid producers are generally 

 entirely absent. On the other hand, the numbers on 

 the litmus-lactose-agar plate will be likely to run into 

 hundreds with a good proportion of red colonies when 

 polluted waters are examined. 



