404 PATHOGENIC BACTERIA. 



2. It may be due to the septicemias established during 

 the course of the disease, the cadaver then presenting an 

 almost pure culture of the other microbes. 



3. It may be due in large measure to renal insufficiency, 

 when the cadaver is found nearly sterile. 



The black vomit is due to the action of gastric acidity 

 upon the blood which has extravasated in the stomach in 

 consequence of the toxic products of the Bacillus icte- 

 roides. 



The Bacillus icteroides produces a toxin the result of 

 whose action corresponds to the essential symptoms of the 

 disease. Animals immune to the infection, or only par- 

 tially susceptible to it, are not much affected by the toxin. 

 Susceptible animals, such as dogs, are profoundly affected. 

 Ten to fifteen minutes after injecting the toxin the 

 animals experience a general rigor; abundant lachryma- 

 tion begins, followed by continued vomiting, first of food, 

 then of mucus. In a short time the animals lie help- 

 less and extended. Hematuria frequently occurs. If the 

 dose be moderate, the dog recovers quickly from the 

 violent attack; but if the quantity of toxin be very large 

 or repeated on successive days, it finally succumbs, pre- 

 senting the anatomical lesions already described as due to 

 infection. 



The proofs of the specificity of the Bacillus icteroides 

 are not limited to the animal experiments quoted. Sana- 

 relli also adduces five experimental inoculations upon 

 men. These inoculations were not made with the bac- 

 teria i. e. were not infection experiments but were 

 made with the filtered sterile toxin, whose action could 

 be more easily controlled. " The injection of the filtered 

 cultures in relatively small doses reproduced in man 

 typical yellow fever, accompanied by all its imposing 

 anatomical and symptomatological retinue. The fever, 

 congestions, hemorrhages, vomiting, steatosis of the liver, 

 cephalalgia, collapse in short, all that complex of symp- 

 tomatic and anatomical elements which in their combina- 

 tion constitute the indivisible basis of the diagnosis of 



