XVI] VIBRIO AND SPIRILLUM 445 



importance for diagnostic purposes, had been conceded and 

 confirmed on almost all sides (see this 3rd edition and my 

 Bacteria in Asiatic Cholera, 1886 and 1887), the proof, how- 

 ever, as to the experimental production of cholera in the 

 guinea-pig, as we have shown above, was far from a satis- 

 factory kind. 



Experiments by ingestion of cultures of cholera vibrios in 

 the human subject have been made in Munich (Pettenkofer 

 and von Emmerich), in Vienna (Strieker), and in Paris 

 (Metchnikoff), and the results of these, though not un- 

 equivocal, were sufficiently instructive to strengthen the 

 position of Koch's view as to the causal relation of the 

 cholera vibrio to Asiatic cholera. 



In a considerable percentage of these experiments it was 

 shown that the ingestion of cultivation of cholera vibrio, 

 that had been kept up through many subcultures in the 

 laboratory, produced more or less severe diarrhoea with the 

 presence of the cholera vibrios in the evacuations as shown 

 by the culture test. In a few the effect was tolerably severe 

 (Pettenkofer and Emmerich), and in one case (a boy) 

 observed by Metchnikoff it was a very good imitation of 

 genuine Asiatic cholera, including the rice-water stools with 

 crowds of the cholera vibrios. It is well established by the 

 older researches of v. Pettenkofer and fully confirmed by 

 the observations made in reference to cholera in India and 

 in Europe down to the most recent times, viz., that in the 

 production of cholera the predisposition of the individual, 

 season, and locaHty are important factors besides the real 

 causa causans or the cholera microbe — the x, y, and z 

 of sanitarians. If then in the above precise and de- 

 hberate experiments with pure cultures of Koch's cholera 

 vibrio by ingestion fair results — even few in number — 

 at a time and locality when and where no cholera exists, are 



