XVI] VIBRIO AND SPIRILLUM 437 



well immunised against living vibrios by previous repeated 

 injection of dead vibrios succumb to a dose of toxin pro- 

 duced by cholera vibrios in serum cultures. (The same 

 also holds good for vibrio Finkler and the toxin produced 

 in serum cultures of this vibrio.) So that the distinction 

 on which I have always insisted, ^ between the action of 

 intracellular poisons of a microbe and that of the toxins 

 produced by the microbe as a result of its metabolism is 

 well founded. 



Koch ^ in his first pamphlet on cholera told us ^ that he 

 had made every imaginable effort to produce cholera in 

 animals experimentally. The experiments of feeding white 

 mice with cholera dejecta, first made by Tiersch and then 

 by Burden Sanderson, were repeated by Koch over and 

 over again on fifty white mice fed with this material (dejecta 

 of cholera patients, and the contents of the intestine of 

 cholera corpses) and with choleraic material after it had 

 begun to decompose, but no result whatever followed ; the 

 mice remained healthy. " We then made experiments on 

 monkeys, cats, poultry, dogs and various other animals 

 that we were able to get hold of, but we were never able 

 to arrive at anything in animals similar to the cholera 

 process. In precisely the same manner we made experi- 

 ments with the cultivations of comma bacilli ; these were 

 given as food in all stages of development. When experi- 

 ments were made by feeding animals with large quantities 

 of comma bacilli, on killing them and examining the con- 

 tents of their stomachs and intestines with a view to find 

 comma bacilli it was seen that the comma bacilli had 

 already perished in the stomSch, and had usually not 



1 Ibidem, 1892, 1893, and 1894. 



^ The following is copied from my Bacleria in Asiatic Cholera. 



^ Coiijeratz zur ErorUrung der Cholcrafrage, Berlin, 1884, p. 27. 



