484 BACTEEWLOG Y. 



twenty times the dose necessary to produce the same 

 effects with the primary poison. 



EXPERIMENTS UPON ANIMALS. As a result of ex- 

 periments for the purpose of determining if the disease 

 can be produced in any of the lower animals it has been 

 found that white mice, monkeys, cats, dogs, poultry, and 

 many other animals are not susceptible to infection by the 

 methods usually employed in inoculation experiments. 

 When animals are fed on pure cultures of the comma 

 bacillus no effect is produced, and the organisms cannot 

 be obtained from the stomach or intestines. They are 

 destroyed in the stomach, and do not reach the intes- 

 tines ; they are not demonstrable in the faeces of these 

 animals. Intravascular injections of a pure culture 

 into rabbits are followed by an illness, from which 

 the animals usually recover in from two to three days ; 

 intraperitoneal injections into white mice are, as a rule, 

 followed by death in from twenty-four to forty-eight 

 hours ; the conditions in both instances most probably 

 resulting from the toxic activities of the poisonous prod- 

 ucts of growth of the organisms present in the culture 

 employed. None of the lower animals suffer spontane- 

 ously from Asiatic cholera. 



The failure to induce cholera in animals by feeding, 

 or by injection of cultures into the stomach, was shown 

 by Nicati and Rietsch 1 to be due to the destructive 

 action of the acid gastric juice on the organisms. They 

 showed that .if cultures of this organism were intro- 

 duced into the alimentary tract of certain animals in 

 such a manner that they would not be subjected to the 



1 Archiv. de Phys. norm, et path., 1885, t. vi., 3e ser. Comptes rendus, 

 xcix., p. 928. Eevue de Hygiene, 1885. Revue de Medecine, 1885, v. 



