504 Profs. Percy Fraiiklaml and Marshall Ward. 



The above tables show that in the steam-sterilised Loch Katrine, 

 water, the typhoid bacilli again underwent no multiplication, but on the 

 contrary steady decline, the last surviving individuals being, however, 

 remarkably persistent. Tims the typhoid bacilli were still discoverable 

 on 9.12.1893, or fifty-one days after their first introduction. This is a 

 much, longer survival than 'in the case either of the steam-sterilised 

 Thames or deep ivell waters. 



In the Loch Katrine water, rendered sterile by filtration, the typhoid 

 bacilli also survived much longer than in either the similarly treated 

 Thames or deep well waters, the bacilli being still discovered on 

 27.11.1893, or thirty-nine days after their first introduction. The filter 

 used in this case was a porous cylinder of infusorial earth as with 

 the Thames and deep well waters. This result again confirms what 

 I found in the previous series of experiments (see pp. 460, 464, 479), 

 viz., that the typhoid bacilli persisted much longer in the porcelain- 

 filtered Lach Katrine than in the porcelain-filtered Thames water. 



