174 MICRO-ORGANISMS IN WATER 



Bacterial Condition of Water filtered through a Chamberland filter 

 and kept at 35 and 22 C. respectively (Freudenreich) 



Filters ~kept at a Temperature of 35 C. 

 Examination 1, after 2 days the water was sterile 



was not sterile 



Filters kept at a Temperature of 22 C. 



Examination 1 after 7 days the water was sterile 

 9 Q 



- 1 ?? U M J? ?5 > 



3 9 



4 10 



5 10 not sterile 



6 10 sterile 



7 ., 11 not sterile 



8 11 ? , sterile 1 



9 11 not sterile T 



10 12 



11 ,, 12 ,, ,, ,, sterile 



12 12 



13 15 



14 15 not sterile 1 



15 ., 18 ,, ,, ,, sterile l 



A filter kept at a temperature of between 15 and 

 18 C. yielded a sterile filtrate even after twenty-one 

 days. From these experiments it would appear that 

 certain bacteria are capable of growing through the 

 filter, and others not ; for whereas in some instances 



1 Freudenreich explains these discrepancies as due partly to differ- 

 ences in the character of the cylinders employed, and partly to differences 

 in the micro-organisms present in the water at different times. 



