324 BACTERIOLOGY. 



salts, and a temperature of 100° C, decompose this 

 substance, leaving behind secondary poisons which 

 possess a similar physiological activity, but only when 

 given in from ten to twenty times the dose necessary 

 to produce the same effects with the primary poison. 



Other members of the vibrio family also, namely, 

 the vibrio Metchnikovi and that of Finkler and 

 Prior (see description of these species), contain, accord- 

 ing to Pfeiffer, closely related poisons. 



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 is 

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

 and many other animals, are not susceptible to in- 

 fection 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 intestines ; they are not demonstrable in 

 the feces of these animals. Intra-vascular injections 

 of pure culture into rabbits are followed by a temporary 

 illness, from which the animals usually recover in from 

 two to three days; intra-peritoneal 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 products of growth of the 

 organism that are present in the culture employed. 

 None of the lower animals have ever been known to 

 suffer from cholera spontaneously. 



The experiments of Nicati and Rietsch, in which the 

 common bile-duct was ligated, and fluid cultures of 



