THE CAUSE OF YELLOW FEVER 111 



effect, also numerous cases in which the wives of 

 yellow fever patients slept in the same bed, or cases 

 in which a patient, through lack of space, w^as placed 

 in the cot newly vacated by a yellow fever case 

 that had died. In no instance was yellow fever 

 contracted. 



In 1793 Dr. Firth of Philadelphia inoculated his 

 arm with the blood taken from a yellow fever patient. 

 He also drank some of the black vomit. No ill effect 

 followed. According to Professor Harrison,^ a Dr. May 

 dropped some black vomit into his eyes and did not 

 get the fever. Since that period all these experiments, 

 with many more besides, have been re-made, with the 

 like negative effect, showing that the secretions, the 

 bedding, and the clothes did not convey infection. 

 But how, then, was the infection conveyed ? Beau- 

 perthuy, as we have seen, tried to explain it, and 

 succeeded half way — the mosquito conveyed the virus, 

 but he failed to observe that the mosquito got its 

 virus from infected man. He supposed that it obtained 

 it from decomposing matter. Just as Ross furnished 

 the clue in the case of the anophelines, so Reed, Carroll, 

 Agramonte, and Lazear solved the question in the 

 case of the stegomyia. Beauperthuy's contention that 

 the mosquito obtained its poison from the soil fitted 

 in with the views then firmly held of the local origin 

 of the disease. It was noted over and over again how 

 the disease clung to certain places and liouses. With 

 the view of throwing light upon the local origin of the 

 disease, more especially in the case of graveyards which 



' Loc. cit. 



