Mosquitoes and Yellow Fever 125 



EXPERIMENTS 



"Two separate lines of work now presented: one, 

 the study of the bacterial flora of the intestine and 

 anaerobic cultures from the blood and various organs; 

 the other, the theory of the transmission of the disease 

 by the mosquito, which had been advanced by Dr. Car- 

 los Finlay in 1881. After due consideration it was de- 

 cided to investigate the latter first. Then arose the 

 question of the tremendous responsibility involved in 

 the use of human beings for experimental purposes. 

 It was concluded that the results themselves, if positive, 

 would be sufficient justification of the undertaking. It 

 was suggested that we subject ourselves to the same 

 risk and this suggestion was accepted by Dr. Reed and 

 Dr. Lazear. It became necessary for Dr. Reed to re- 

 turn to the United States and the work was begun 

 by Dr. Lazear, who applied infected mosquitoes to a 

 number of persons, himself included, without result. 

 On the afternoon of July 27, 1900, I submitted myself 

 to the bite of an infected mosquito applied by Dr. La- 

 zear. The insect had been reared and hatched in the 

 laboratory, had been caused to feed upon four cases 

 of yellow fever, two of them severe, and two mild. The 

 first patient, a severe case, was bitten twelve days be- 

 fore; the second, third and fourth patients had been 

 bitten six, four and two days previously, and were in 

 character mild, severe and mild respectively. In writ- 

 ing to Dr. Reed that night of the incident, I remarked 



