82 Elements of Water Bacteriology. 



always very rapidly reduced (Frankland, 1894). More 

 recently, Jordan (Jordan, 1905) has demonstrated that 

 the typhoid bacillus may be isolated from mixed cultures 

 of B. typhi and B. coli in tap water and sewage after 

 thirty-four days, with unchanged agglutinative powers. 

 On the other hand, Jordan, Russell and Zeit (Jordan, 

 Russell and Zeit, 1904), and Russell and Fuller (Russell 

 and Fuller, 1906) have shown that in unsterilized lake 

 water, river water, and sewage, the life of the organism 

 may not exceed five days. Whipple and Mayer (Whipple 

 and Mayer, 1906) have- ascribed to dissolved oxygen a 

 decided effect upon the viability of the typhoid bacillus 

 in water, absence of oxygen tending to weaken the 

 organism. 



Epidemiological evidence confirms the results of Laws 

 and Andrewes which teach that the number of typhoid 

 baciUi even in polluted water is probably never very great, 

 while the fate of Lowell and Lawrence in 1890-91 and 

 the more recent epidemics at Butler, Pa., and Ithaca, N. Y., 

 seem strongly to demonstrate that even a small number 

 of virulent organisms can bring about an almost wholesale 

 infection. Indeed, if the virulent organism were as 

 abundant as some results would indicate (Remlinger 

 and Schneider, 1897), the human race would long since 

 have been exterminated. On the whole it is clear that a 

 negative test for the typhoid bacillus means practically 

 nothing. Since this is so, and since a positive result is 

 always open to serious doubt, the search for the typhoid 



