532 APPLICATION OF METHODS OF BACTERIOLOGY 



selves, and is probably an integral constituent of them, for 

 the vitality of the cholera spirilla can be destroyed by means 

 of chloroform or thymol, or by drying, without apparently 

 any alteration of this poisonous body. Absolute alcohol, 

 concentrated solutions of neutral salts, and a temperature 

 of 100° C, decompose this substance, leaving intact second- 

 ary 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. 



Experiments upon Animals. — As a result of experiments 

 for the purpose of determining if the disease can be pro- 

 duced 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 intestines; they are not 

 demonstrable in the feces 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 specific 

 poisons contained in the cultures used. 



None of the lower animals suffer spontaneously from 

 Asiatic cholera. 



The failure to induce cholera in animals by feeding or 

 by injection of cultures into the stomach, was shown by 



