522 PATHOGENIC BACTERIA. 



with marked fatty degeneration. The whole digestive 

 tract is the seat of hemorrhagic gastro-enteritis comparable 

 in intensity only to poisoning by cyanid of potassium. 



Experiments upon monkeys were also of interest, in- 

 asmuch as they demonstrated the possibility of obtaining 

 fatty degeneration more extensive than is observed in 

 man. In one case the liver was transformed into a mass 

 of fatty substance similar to wax. 



Goats and sheep are also very sensitive to the icteroid 

 virus, and the lesions described also occur in them. 



The death of a yellow fever victim is the result of one 

 of three causes: 



i. It may be due to the specific infection principally, 

 when the Bacillus icteroides is found in the cadaver in 

 a certain quantity and in a state of relative purity. 



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. 



