ISOLATION OF SPECIFIC PATHOGEN ES. 53 



(15) Agglutination. — As a rule, (15) Marked agglutination with 

 no agglutination with a dilute anti- dilute anti-typhoid serum. 

 typhoid serum. 



Of the many observers who have reported the isola- 

 tion of the typhoid bacillus from water all but the most 

 recent are quite discredited, on account of the insufficiency 

 of their confirmatory tests, and even the latest results 

 should be received with caution. Since the introduction 

 of the Widal (Widal, 1896) reaction, founded on the 

 fact that typhoid bacilli examined under the microscope 

 in the diluted blood-serum of a typhoid patient lose their 

 motility and "agglutinate" or clump together, an import- 

 ant aid has been furnished in the diagnosis. Yet serum 

 tests are notably erratic, and insufficient to identify an 

 organism without an exhaustive study of biochemical 

 reactions, especially as many organisms are agglutinated 

 by typhoid serum in a more or less dilute solution. The 

 discovery of the Bacillus dysenteric of Shiga,* which 

 closely resembles the typhoid bacillus, has made the 

 identification of the latter more dubious than ever. 



It seems probable that in some recent cases the typhoid 

 bacillus has indeed actually been isolated from polluted 

 water, as by Kiibler and Neufeld (Kubler and Neufeld, 

 1899), who examined a farmhouse well at Neumark in 

 1899, and Fischer and Flatau (Fischer and Flatau, 1901), 

 who discovered an organism responding to a most ex- 

 haustive series of tests for the typhoid bacillus in a well at 



* For an account of the Biology of B. dysenteriae the student is 

 referred to an article by Dombrowsky, 1903. 



