2 THE BACTERIA IN ASIATIC CHOLERA. [INT. 



proved of value from an epidemiological and general sanitary 

 point of view has been gained irrespective of any knowledge 

 of bacteria. The laws governing the spread of cholera are 

 and have been well understood by sanitarians ; the fact that 

 cholera, like other infectious diseases, is a communicable 

 disorder spreading from a focus of infection has been long 

 known ; and the measures required (and now almost 

 everywhere admitted as necessary) in order to check its 

 spread have been carried out for many years, and without 

 any exact knowledge of diseased-germs. True it was always 

 felt, and a reference to the theoretical parts of the papers by 

 v. Pettenkofer, Bryden, Budd, Parkes, and others fully bears 

 this out, that the knowledge thus gained was of a purely 

 empirical kind, no direct or exact experiment being possible 

 to demonstrate the truth or fallacy of the various measures 

 recommended and employed ; and this again was entirely 

 due to the fact that the nature and character of the infective 

 essence of the disease, or the contagium (used here in its 

 wider sense), was unknown. While on the one hand there 

 can be no doubt that the discovery of the cholera-germ 

 (which I may at once say has not yet been made) could 

 not in any way alter the nature and application of the 

 general laws of sanitary science, as specially applied to the 

 group of infectious diseases dependent on filth and accord- 

 ing to the general consensus of experienced observers, 

 Asiatic cholera belongs to this group there can be, on the 

 other hand, no doubt that the identification of a cholera- 

 germ, the knowledge, which from such a discovery would 

 inevitably follow, of its nature and mode of spread, of its 

 mode of alteration by temperature, soil, and season, would 

 unquestionably lead to a more specific application of means 

 to ends than has hitherto been the case. Besides, by an 

 exact knowledge of the cholera-germ, we should be enabled 



