Mosquitoes and Yellow Fever 203 



days his lite hung in the balance. During his convalescence an 

 incident occurred which showed how the theory of mosquito trans- 

 mission of the disease was generally regarded. We quote from Dr. 

 Kelly: "One of his nurses who came from Tennessee had had con- 

 siderable experience with yellow fever, having indeed, lost her hus- 

 band and several children from it. One day early in his illness Dr. 

 Carroll mentioned to her that he had contracted the disease through 

 the bite of a mosquito, and noticed that she looked surprised. Some 

 time later, when well enough to look over the daily records of his 

 condition, he found this entry: 'Says he got his illness through the 

 bite of a mosquito, — delirious'." 



The second case was that of an American who was bitten by four 

 mosquitoes, two of which had bitten severe (fatal) cases of yellow 

 fever twelve days previously, one of which had bitten a severe case 

 (second day) sixteen days before and one which had bitten a severe 

 case eight days before. Five days later, the subject developed a well 

 pronounced but mild case of the disease. 



In the meantime, another member of the Commission, Dr. Lazear, 

 was accidentally bitten by a mosquito while collecting blood from 

 yellow fever patients. Five days later he contracted a typical case 

 which resulted fatally. 



So clear was the evidence from these preliminary experiments 

 that the commission felt warranted in announcing, October 27, 1900, 

 that, "The mosquito serves as the intermediate host for the parasite 

 of yellow fever, and it is highly probable that the disease is only 

 propagated through the bite of this insect." 



In order to extend the experimental evidence under conditions 

 which could leave no possibility of infection from other sources, a 

 special experimental sanitary station, named in honor of the deceased 

 member of the Commission, was established in an open field near 

 the town of Quemados, Cuba. Here there were constructed two small 

 buildings known respectively as the "infected clothing building" 

 and the "infected mosquito building." 



The infected clothing building, 14 x 20 feet in size, was purposely 

 so constructed as to exclude anything like efficient ventilation, but 

 was thoroughly screened to prevent the entrance of mosquitoes. 

 Into this building were brought sheets, pillow-slips, blankets, etc., 

 contaminated by contact with cases of yellow fever and their dis- 

 charges, — ^many of them purposely soiled with a liberal quantity of 

 black vomit, urine, and fecal matter from patients sick with yellow 



