*24 BACTERIOLOGICAL EXAMINATION OF WATER. 



vsuspected organisms and the serum from typhoid patients, and 

 also with the serum from a guinea-pig (immunised by injecting 

 1 c.c. of a forty-eight hours broth culture per 0'3 kilogramme 

 of body-weight) diluted 1-50. Lastly, according to Fodor and 

 Rigler's recommendation, forty-eight hours broth cultures of 

 the suspected organisms were injected into guinea-pigs and 

 dogs. Specimens of blood from these animals were taken after 

 eight to ten days, centrifugalised, and then tested with true 

 cultures of B. typhosus, B. coli, and the organisms which had 

 been used for the immunisation. From the 28 plates 157 

 suspicious cultures were obtained, but of these only 61 corre- 

 sponded to B. typhosus in motility, staining reactions, and 

 growth in gelatine-stab. Out of 61 cultures, however, only 31 

 grew typically in sugar-agar, milk, and broth, and only 11 of 

 these were agglutinated by the serum from typhoid patients 

 diluted 1-50. Out of 9 cultures tested 7 were agglu- 

 tinated by the serum of the guinea-pig immunised with B. 

 typhosus diluted 1-50. Eight guinea-pigs and three dogs 

 were then inoculated with the 11 cultures which had shown 

 a reaction with the serum of the typhoid patients. The serum 

 diluted 1-50 from each of the guinea-pigs and dogs agglu- 

 tinated the special organisms which had been used for their 

 immunisation; and also, for the most part, the serum from all 

 the animals agglutinated all the organisms which had been used 

 for the injections. But, with one exception, the sera failed to 

 agglutinate a broth culture of a true typhoid bacillus. 

 Genersich could not explain the cause of this failure, but 

 suggested that the supposed typhoid bacilli, isolated from water, 

 had much less virulence than the typhoid bacilli isolated from 

 the spleens of typhoid patients, and so were unable to produce 

 a serum which would agglutinate the latter bacilli. 



B. Fischer and G. Flatau in January 1901 reported the 

 discovery of the typhoid bacillus in water from a well in the 

 town of Rellingen. Plates were made with varying quantities 

 of the water added to ordinary and carbolic acid (0'05 per cent.) 

 gelatine ; srrface plates with the same media were also prepared. 

 On the surface plates made with carbolic acid five suspicious 

 colonies appeared, but only one of these failed to produce gas in 

 glucose-agar. This organism was then carefully studied. It 



