466 



Profs. Percy Frankland and Marshall Ward. 



Infection of Loch Katrine Water with Typhoid and B. coli commands, 



4.7.1893. 



The cultures of the bacilli employed were on agar, and in both 

 cases twenty-eight days old. In the case of the typhoid bacillus 40 

 needle-loops, and in that of the coli 25 loops, were taken from the 

 surface of the agar, removing as little of the culture-material as 

 possible, and introduced in each case into 50 c.c. of steam-sterilised 

 water, which was then violently shaken to ensure disintegration of 

 the bacterial masses. The experimental waters were then infected 

 from these water-attenuations as follows : 



These infected waters, after thorough agitation, were then, as in 

 previous experiments, subdivided amongst a number of small sterile 

 conical flasks, plugged with sterile cotton-wool ; in each case some of 

 these flasks were placed in the incubator at 19 C., whilst others were 

 kept in a refrigerator at 6 8 C. The uninfected unsterilised Loch 

 Katrine water was also put into similar flasks, which were kept under 

 precisely similar conditions for control. 



1. Bacteriological Examination of the Unsterilised Uninfected Loch 

 Katrine Water. 



The control-waters were submitted to periodical examination both 

 by gelatine-plate and phenol-broth culture, with the following 



results : 



