120 



witli another quantity of liiglily active hacteiiopliage (0,2 cc. to JO 

 cc. of liquid. The bacteriopiiage was still active in a dilution of 

 10~i°). Bacteriopiiage was superadded to demonstrate its influence 

 still more conclusively than could be done with the bacteriophage 

 already occurring in the Vlietwater. 



The subjoined table shows the details of the experiment and gives 

 a survey of the results achieved: 



The tests of the 2"'' series were conducted as follows : 



The tluid of two tlasks, each holding 0,5 L. of bacteriophage- 

 containing Vlietwater, was infected with such an amount ofFlexner- 

 culture as to render it quite turbid. 



To the fluid of one of the tlasks 20 mgms of KCN was added, 

 after which the flask was well fitted with a rubber stopper. Both 

 flasks were placed at room-temperature in diffuse daylight. 



After a week the fluid of the flask without KCN had become 

 quite clear, whereas the KCN-flask still contained a turbid fluid. In 

 the former a large number of protozoa were found, which were 

 lacking in the latter. 



On the eleventh day of the experiment the KCN flask was also 

 getting more lucid and protozoa were noticeable in it. After a 

 fortnight the fluid in either flask was clear. 



1) K. B. is a Flexnerstock resistant to any bacteriophage action. 



