QUALITATIVE BACTERIOLOGICAL ANALYSIS. 227 



they often found in water, soil, and human fasces bacilli which 

 strongly resembled the B. typhosus in all points except reaction 

 to specific agglutinins and pathogenicity to animals. They 

 believe that there are varieties of the true B. typhosus, and 

 consider that this organism exists naturally in air, water, and 

 earth, but how it obtains its pathogenic action is not yet 

 known ; possibly privation and fatigue are important factors. 



Whether it be true that B. coli can be converted into 

 B. typhosus, as Rodet believes, or that the B. typhosus naturally 

 exists in water, &c., in an abortive form, as Remlinger and 

 Schneider consider probable, the fact remains that up to the 

 present time most bacteriologists have failed to isolate the 

 typhoid bacillus from suspected water supplies. Consequently 

 it would be a very important matter for hygienists if they 

 could, in the absence of the discovery of the B. typhosus, say 

 that a water supply had been infected by the specific dejecta 

 of enteric fever. With this end in view I have lately made a 

 special study of the varieties of B. coli which are associated 

 with the typhoid bacillus in the dejecta of patients suffering 

 from enteric fever. I hoped that the varieties in question 

 might show cultural characteristics or reactions to specific sera, 

 which would enable them to be distinguished from the varieties 

 of B. coli present in the stools of healthy people. One hundred 

 and fifty different cultures were examined, eighty being derived 

 from the stools of patients suffering from typhoid fever and seventy 

 from the stools of healthy men. The stools of the enteric fever 

 patients were obtained during the third and fourth weeks of the 

 disease and also from the intestines after death had occurred. 

 A loopful of the stool was stroked over the surface of a series of 

 plates containing solidified gelatine. The first two plates generally 

 liquefied, but the remaining plates showed discrete colonies which 

 developed satisfactorily. Typical colonies were fished and planted 

 out on a gar slopes, which were then incubated at 37 C. for 

 twenty-four hours. The growths which resulted were used for 

 agglutination experiments and planted out in the various media. 



Agglutination Experiments. The twenty-four hours growth 

 was made into an emulsion with broth and then mixed with an 

 equal amount of horse's anti-typhoid serum, so as to make 

 final dilutions of the mixed emulsion and serum in the 



