WATER 49 



Of recent investigations upon this subject the following are 

 two of the most important. 



Jordan, Russell and Zeit 1 carried out three independent series 

 of experiments which later were re-investigated by Russell and 

 Fuller 2 . They used recently isolated B. typhosus strains and the 

 bacilli were suspended in the water in celloidin or parchment 

 sacs. The waters used for experiment were lake and river water 

 and the impure Chicago Drainage Canal water. 



Jordan, Russell and Zeit concluded that " under conditions 

 that probably closely simulate those in nature, the vast majority 

 of typhoid bacilli introduced into the several waters studied, 

 perished within three to four days." They however suggested that 

 specially resistant cells may be able to live for longer periods. 



Their experiments show the relative rather than the ultimate 

 disappearance of the bacilli, since the whole bulk of fluid was not 

 examined for the typhoid bacillus but only one c.c. or other small 

 amount. 



Houston 3 has recently carried out some extended investiga- 

 tions. In one series " cultivated " bacilli were added to raw 

 river water stored in the laboratory in partially filled stoppered 

 bottles. In these experiments the vast majority of the bacilli 

 perished within one week, but a few specially resistant strains 

 persisted for several weeks, the final extinction of the bacilli (as 

 judged by inability to isolate it from 100 c.c. of the water) only 

 taking place after nine weeks. 



In a second series the typhoid bacilli were added to the water 

 direct from actual typhoid bacilli carrier cases, the bacilli being 

 added either directly centrifugalized from urine or in the urine 

 itself. 



In the first experiment the first week effected a percentage 

 reduction of 99*99 to 100 in the number of typhoid bacilli, their 

 ultimate death (as judged by inability to isolate it from 100 c.c.) 

 taking place either within one week or by the second week. 

 Subsequent experiments gave similar results but in one experi- 

 ment, using an outdoor tank, the uncultivated bacilli were still 

 found in looc.c. after three weeks. 



1 Journ. of Infectious Diseases, 1904, vol. I, p. 641. 



2 Ibid. Supplement No. 2, Feb. 1906, p. 40. 8 Seventh Research Report. 

 S. \V. 4 



