DETECTION OF PATHOGENIC BACTERIA IN WATER 261 



bacillus has been discovered in the mud at the bottom 

 of a well used for drinking purposes. 1 Numerous cases 

 of splenic fever had broken out amongst some sheep 

 on a farm in the south of Russia, every precaution was 

 taken to root out the disease, but healthy animals 

 invariably developed symptoms of anthrax when they 

 were brought back to one particular sheep-fold. At 

 last suspicion fell on a well which was used for the 

 animals in this fold, and a careful examination revealed 

 beyond doubt the presence of anthrax germs in the 

 sediment. On the closing of the well no further cases 

 of anthrax took place. That the germs of anthrax 

 had gained access to the well is certain, and the possi- 

 bility of such contamination taking place through the 

 drainage from soil shows how desirable is the disposal 

 of infected carcases by cremation rather than by burial. 

 Thus a number of bacteria, possessing pathogenic 

 properties of the most pronounced character, have been 

 detected in natural waters from time to time. Several 

 of the organisms referred to above, however, are in some 

 respects of subsidiary interest only, as they are not 

 pathogenic to man, whilst in no case is the propagation 

 of any of the above diseases commonly associated with 

 water. In fact, practically the only human diseases of 

 the zymotic class, which are believed to be commonly 

 propagated by water, are Asiatic cholera and typhoid 

 fever ; but the detection of the exciting causes of these 

 diseases in w r ater, or, for the matter of that, in any 

 other materials, is surrounded with special difficulties, 

 because these diseases being apparently restricted to 

 the human species and unknown amongst the lower 

 animals, it is impossible to test for the presence of their 

 exciting causes by- direct experiments on animals. But 



1 ' Bacteries Charbonneuses dans la Vase du Fond d'un Puits,' Dia- 

 troptoff, Annales de VInstitut Pasteur, vol. vii., 1893, p. 286. 



