Lesions 537 



asmuch as they demonstrate 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 thought by Sanarelli 

 to be the result of one of three causes : 



1. It may be due to the specific infection principally, when 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 Bacillus icteroides. 



Bacillus icteroides is said to produce a toxin the result of 

 whose action corresponds to the essential symptoms of 

 yellow fever. Animals immune against the infection, or only 

 partially susceptible to it, are not much affected by the 

 toxin. Susceptible animals, such as dogs, are profoundly 

 affected. In from ten to fifteen minutes after injecting the 

 toxin the animals experience a general rigor and abundant 

 lachrymation, followed by continued vomiting, first of food, 

 then of mucus. In a short time they lie helpless and ex- 

 tended. Hematuria frequently occurs. If the dose be 

 moderate, recovery quickly follows the violent attack; but 

 if the quantity of toxin be very large or repeated on succes- 

 sive days, it finally succumbs, presenting the anatomic 

 lesions already described. 



To prove the specificity of Bacillus icteroides, Sanarelli 

 adduces five experimental inoculations upon men. These 

 were not made with the bacteria, i. e., were not infection 

 experiments, but were made with the filtered sterile toxin, 

 whose action could be controlled. 



"The injection of the filtered cultures in relatively small doses 

 reproduced in man typical yellow fever, accompanied by all its im- 

 posing anatomic and symptomatologic retinue the fever, conges- 

 tions, hemorrhages, vomiting, steatosis of the liver, cephalalgia, col- 

 lapsein short, all that complex of symptomatic and anatomic elements 

 which in their combination constitute the indivisible basis of the diag- 

 nosis of yellow fever. This fact is not only striking evidence in favor 



