520 



Profs. Percy Frankland and Marshall Ward. 



sterile beakers, and kept in a dark cupboard at a temperature of 

 9 11 C. All of these waters were periodically submitted to plate 

 cultivation, as well as tested for typhoid bacilli by the method of 

 phenol broth -culture. The results of these examinations are recorded 

 in the following tables :- 



Uuinfected Unsterilised Thames Water (16.1.1894). 



The above table shows that the sample of Thames water employed 

 contained a considerable total number of bacteria, but of these un- 

 usually few caused liquefaction of the gelatine. Moreover, the water 

 was characterised by the number of bacteria remaining practically 

 stationary during the period (five weeks) over which these experi- 

 ments extended, a phenomenon which I have already pointed out is 

 not unfrequently met with in the case of surface waters. 



