EXAMINATION OF WATER 309 



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 lead to as decided a condemnation of the 

 water as though an organism possessing the precise mor- 

 phological and cultural characters of the Eberth-Gaffky 

 bacillus were isolated. 



While we would not agree with those who would regard 

 the bacteriological examination of water as useless, we still 

 further dissent from the view — if, indeed, it is seriously 

 held by any — that the biological examination can in the 

 smallest degree supplant the chemical analysis of water, 

 which, on account of the valuable data it yields, must 

 always remain an integral part of the examination of 

 potable water. 



The most enthusiastic bacteriologist cannot deny that the 

 specific organism may have been present in a given water- 

 supply a week ago, and at the time of examination have 

 disappeared. The incubation period of enteric fever is 

 about fourteen days ; so that if a sample of drinking-water 

 were sent for examination when the disease declared itself, 

 it might easily be three weeks since the conveyance of 

 the infection, and during this time the Eberth-Gaffky 



* ' Keport on the Eesults of the Investigations on the Micro-Organisms 

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



