402 APPLIED BACTERIOLOGY 



bolised as to totally inhibit typhoid, there appears at 

 present no means of separating typhoid from them, unless 

 the former is present in such abundance as to be detectable 

 by plate culture, either in the usual form, or as modified by 

 Eisner. 



As soon as the colonies which develop on the carbolised 

 or potato-gelatine become sufficiently advanced they are 

 examined with a lens, and any suspicious colonies are care- 

 fully subcultured into faintly alkaline sterile milk-tubes, 

 which are then incubated at 37° C. for thirty-six hours. 

 The milk-tubes are then examined, and any that have 

 become coagulated are rejected as certainly not typhoid. 



From the tubes that have not coagulated the following 

 subcultures are prepared : {a) Gelatine ' streak ' culture ; 

 (6) gelatine ' shake ' culture ; (c) broth culture. 



The gelatine cultures are kept for three days at a 

 temperature of from 18° to 20° C. The broth-tubes are 

 incubated at blood-heat for the same length of time, and 

 then tested by the indol reaction. 



Messrs. Laws and Andrewes* failed, after a most pro- 

 longed investigation, to find the typhoid bacillus in the 

 London sewage from the Barking and Crossness outfalls, 

 but they found it present, as would be expected, in the 

 sewage from the Homerton Fever Hospital. 



With respect to the question of the detection of the 

 typhoid bacillus in water, we are satisfied that the Eberth- 

 Gaffky bacillus can be, and has actually been, detected and 

 isolated from water, though some of the cases in which it 

 has been reported may rest upon insufficient evidence. We 

 would, however, consider that the discovery of any of the 

 pseudo-typhoid organisms, such as have been already 

 mentioned, should, in the present state of our knowledge, 



* ' Eeport on the Eesults of the Investigations on the Mioro-Organisms 

 of Sewage,' presented to the London County Council, December, 1894. 



