ISOLATION OF SPECIFIC PATHOGENES 91 



isms gave positive agglutination tests, as well as the 

 usual cultural reactions, are also cited by Willson. 



During the last 5 years a number of successful isola- 

 tions of the typhoid bacillus have been reported in 

 America. An organism obtained from the water-supply 

 of Scran ton, Pa., in 1907, by simple enrichment in 

 Parietti bouillon, was identified as the typhoid bacillus 

 by Prof. Fox after a very careful series of tests with 

 immune sera (Pennsylvania, 1908). The most impor- 

 tant results have been achieved, however, by Jackson 

 with lactose bile enrichment and subsequent plating on 

 Hesse agar. He reports the isolation of B. typhi from 

 10 c.c. samples of the Grass River at Canton, N. Y., 

 and of a pond and stream at Hastings, N. Y., (both 

 used as sources of water-supply) and from two i c.c. 

 samples of the Hudson River near Hastings at the 

 time of the typhoid epidemic there (Jackson and Melia, 

 1909). Stokes and Hachtel (1910) by the same method 

 found organisms corresponding to typhoid_in their general 

 cultural reactions in four samples of surface-waters 

 (two of them from an impounding reservoir of the 

 Baltimore supply), in the sediment of a school well 

 supposed to have caused typhoid fever, in a sewage- 

 polluted stream and in two samples of market oysters. 

 These organisms agglutinated with the blood of typhoid 

 patients in 1/50 and i/ioo dilutions, but with an 

 immune serum producing agglutination with a standard 

 laboratory typhoid culture in dilution of 1/25,000 

 these water organisms would only agglutinate in 

 dilutions of 1/250 or 1/500. Their identity must 

 therefore be regarded as somewhat doubtful. The 



