PATHOGENIC BACTERIA 



365 



of the typhoid bacillus is much longer than in water. Levy and 

 Kayser found typhoid bacilli in soil that had been manured fourteen 

 days previously with the five-months-old contents of a vault. The 

 evidence that any genuine multiplication can take place iiv the 



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soil is not convincing, but it has been proved that the bacillus 

 may be carried by water-currents to a considerable distance from 

 the point where it was first introduced. Infection of wells and 

 small water-courses is thus brought about sometimes by the wash- 



