HEALTH AND DISEASE 337 



mosquito that had bitten a yellow fever patient in the first three days of 

 his illness, and had then been kept for at least 1 2 days before it was allowed 

 to bite a human being who had never had yellow fever. If that plan were 

 followed, the person bitten would generally come down with the disease 

 within six days. It now became clear as to why it took so long for a case 

 of yellow fever to infect a house. Mosquitoes had to bite the patient during 

 the first three days of his illness, then 12 days had to go by before they 

 could pass on the disease by biting another person. But after that interval 

 of 12 days they were a menace to everyone who entered the immediate 

 neighborhood. 



ANOTHER SUSPECT 



In a detective story not only must the villain be proved guilty but all 

 other suspects must be proved innocent. Almost everyone at that time 

 thought yellow fever was carried by fomites — that is, by excretions of 

 yellow fever patients in the articles of clothing, bedding, or other mate- 

 rials that had been contaminated by contact with people who had the 

 disease. That belief resulted in the destruction of a great deal of valuable 

 property supposed to be infected, and worked a real hardship on merchants 

 trading in infected ports. 



FOMITES PROVED INNOCENT 



Walter Reed and his associates now set to work to prove that fomites 

 do not carry the disease. For this purpose a small frame house consisting 

 of one room 14 by 20 feet in size was erected at Camp Lazear. It was tightly 

 built, and the doors and windows were so placed as to admit as little sun- 

 light and air as possible. A coal-oil stove kept the temperature at 90 degrees 

 during the day, and the atmosphere was provided with moisture. The room 

 was thus kept like the hold of a ship in the tropics — warm, dark, and moist. 



The building was now ready for the experiment. Three large boxes filled 

 with sheets, pillow slips, blankets, etc., contaminated by contact with cases 

 of yellow fever, were placed inside; and on November 30, 1900, Dr. R. P. 

 Cooke, acting Assistant Surgeon, United States Army, and two privates of 

 the Hospital Corps, all nonimmune young Americans, entered the build- 

 ing. They unpacked the boxes, giving each article a thorough shaking in 

 order to fill the air with the specific agent of yellow fever if it was con- 

 tained in these fomites. They then made the beds with the soiled bed cloth- 

 ing and slept in them. Various contaminated articles were hung about the 

 bed in which Dr. Cooke slept. For 20 nights this room was occupied by 

 these nonimmunes. They packed up the soiled articles every morning and 

 unpacked them at night, but not one of the men developed yellow fever. 



From December 21, 1900, to January 10, 1901, the room was again oc- 

 cupied by two nonimmune young Americans. These men slept every night 

 in the soiled garments and on the bedding used by yellow fever patients 



