60 BACTERIAL POISONS. 



for twenty-four hours, became so poisonous that 100 c. c. of 

 it introduced into the stomach of a full-grown cat caused 

 death. Now made plate cultures from the cheese and 

 from the spleen and liver of the dead animals, and suc- 

 ceeded in identifying one germ as common to both. Ster- 

 ilized milk inoculated with a pure culture of this germ, and 

 kept in the incubator, proved fatal to cats. But with the 

 advent of cold weather the germ lost its toxicogenic prop- 

 erties, which were not restored by subsequent cultivation in 

 the incubator. 



" In a second class of samples, the poisonous character 

 of the cheese was not confirmed by direct feeding. Cats, 

 rats, and dogs were fed with the same quantities as above, 

 without any appreciable effect. The report made upon the 

 samples was as follows : 



" ' Animals fed upon the cheese were not affected. Tyro- 

 toxicon could not be found. The sickness in the people 

 was probably due to some other cause.' 



" The last sentence of this report was probably wrong, as 

 will be shown from the following experiment. Two kilo- 

 grammes of a cheese of this class was extracted repeatedly 

 with absolute alcohol. The part insoluble in alcohol was 

 then extracted with water. The aqueous extract, after 

 filtration, was allowed to fall slowly into three times its 

 volume of absolute alcohol. A voluminous, flocculent 

 precipitate resulted. After twenty-four hours the super- 

 natant fluid was decanted, and the precipitate was dissolved 

 in water and re-precipitated with absolute alcohol ; then it 

 was collected and speedily dried on porous plates. A small 

 bit of this precipitate was dissolved in water ; and forty 

 drops of this solution, injected under the skin on the back 

 of cats, produced invariably within one hour vomiting and 

 purging. After the partial collapse which followed the 

 vomiting and purging, and which was evidenced by the 

 animal sitting with its chin resting on the floor, recovery 

 gradually followed. The same amount of the solution 

 injected into the abdominal cavity of white rats rendered 

 the animals within ten or fifteen minutes perfectly limp, 

 and the only evidence of life observed was rapid respiratory 



