288 TEXT-BOOK OF BACTERIOLOGY. 



that separation of germs without which we cannot succeed in ob- 

 taining- reliable pure cultures. 



Koch had in the second cholera conference pointed out these 

 defect's of Emmerich's procedure. He said that it reminded him 

 " of Hallier's manner of instituting- his cholera investigations, who 

 had a bottle with cholera discharges sent to him from Berlin, kept 

 it corked up till the following spring, and then investigated with 

 all possible caution. Emmerich's mistake is not quite so great, 

 but at bottom it is the same." 



This declaration of distrust proved afterward to be amply justi- 

 fied. 



Weisser has, in fact, reached results dealing the death-blow to 

 Emmerich's assertions* 



When we first considered the plate process in examining faeces, 

 we found a kind of bacterium on the plate whose colonies in appear- 

 ance fully resembled those of Emmerich's bacilli. This kind of bac- 

 terium is an almost regular inhabitant of the human intestines, and 

 was but rarely missed on the many hundreds of faeces plates pre- 

 pared in our laboratory. The same micro-organisms ma}^ be ob- 

 tained also from corpses of animals which have been dead for some 

 length of time, from putrefying liquids, etc. And Weisser has suc- 

 ceeded, by the most detailed experiments, in establishing that this 

 fasces bacillus agrees exactly with Emmerich's ie Neapolitan bacil- 

 lus" as regards the morphological properties as well as their 

 biological functions and their pathogenic influence upon animals. 



Emmerich's bacilli are nothing else than ordinary faeces bac- 

 teria, and Emmerich's assertion that " these fungi are in an essen- 

 tial etiological relation to cholera asiatica " falls herewith to the 

 ground. 



XII. BACILLUS TYPHOSUS. 



There are a number of diseases of infectious origin whose real 

 nature is so apparent that it has never been in doubt ; as, for in- 

 stance syphilis. There are other diseases, on the other hand, in 

 which their true nature was so skilfully concealed that it has 

 only been gradually ascertained; as, for instance, tuberculosis and 

 typhoid fever. A correct idea of the morbid changes has been re- 

 tarded by the circumstance that the definitions of infection and 

 contagion were not kept apart with sufficient distinctness, and 

 that one was rejected if the other could not be established. A 

 conclusive understanding as to tuberculosis and typhus abdomi- 

 nalis was obtained only after long efforts. 



Typhus abdominalis and spotted typhus, now regarded as wholly 



