INSECTS AS INTERMEDIATE HOSTS 



407 



this disease is not yet known, it is certain that, like malaria, it requires 

 two hosts for completing its life cycle. At the close of the Spanish- 

 American War a commission of American physicians undertook to 

 find out whether the mosquito was really the intermediary in the 

 transmission of the disease, as had been suspected by many students 

 of the subject. The commission consisted of Dr. Walter Reed, 



FIG. 211. Camp Lazear 



In this building was conducted that part of the yellow-fever experiments which proved 

 that the disease is not transmitted by infected clothing etc. The cabin consisted of a 

 room, 14 by 20 feet, with two small windows facing south, closed with wire screens. 

 Heavy wooden shutters excluded the sunlight. Entrance was through a small vestibule 

 on the same side as the windows, protected by a wooden door and a screen door and 

 separated from the main room by a screen door, to make perfectly certain that no 

 mosquitoes could get in. This house was kept closed during the daytime and had a 

 temperature of from 92 to 95 F. It was occupied for twenty nights by three American 

 volunteers, and the test was repeated twice 



Dr. James Carroll, and Dr. Jesse W. Lazear, and they were assisted by 

 a Cuban, Aristide Agramonte, who had recovered from the disease and 

 was therefore immune. A camp was established in which two cottages 

 were erected. In one of these the ventilation was intentionally very 

 poor. In the other there was a mosquito-tight screen separating the* 

 two halves, and the ventilation was very good. Both cottages were 

 well screened to prevent the entrance or escape of mosquitoes. In 

 the first cottage three volunteers received cases of clothing and bed- 

 ding from men who were suffering from yellow fever, or who had 



