294 



MICRO-ORGANISMS IN WATER 



The results obtained by Kraus with unsterilised 

 waters are given in greater detail in the following 

 table, in which the typhoid bacilli are shown to have 

 either disappeared or, at any rate, to have been no 

 longer demonstrable when the ordinary water bacteria 

 began to assert themselves. No special methods were, 

 however, adopted for the separate identification of the 

 typhoid organism in the presence of the ordinary 

 water bacteria. 



Typhoid Bacillus 



From Table I. above it will be seen that a very 

 considerable amount of attention has been given by 

 numerous investigators to this all-important question 

 of the vitality of typhoid bacilli in water. With regard 

 to the behaviour of these micro-organisms in sterilised 

 waters there is almost complete unanimity, and there 

 can be no doubt that in these, even in sterilised dis- 

 tilled water, the bacilli will retain their vitality over 

 considerable periods of time, at any rate for upwards 

 of one month, although, of course, it is quite possible 

 that in individual cases (depending on the strength or 

 weakness of the cultures employed) they may perish in 

 a shorter period of time. 



Of far greater importance from a practical point 

 of view is the deportment of the typhoid bacilli in un- 



