Dr. Reed then announced that he would disinfect the room so that it would no longer give yellow fever. When it was prepared, he again placed a non-immune in each room, left them there for several days, and they remained perfectly well. He explained that he disinfected the room by simply catching all the stegomyia mosquitoes which he had formerly liberated in the room. This demonstration made a very profound impression. Many, however, still urged that while it was evident that the female stegomyia mosquito could convey yellow fever, it was equally evident from the history of epidemics of this disease that it could be and was generally conveyed in other ways, such as soiled clothing, bedding, the bodies of yellow-fever dead, persons sick of the disease, etc. Dr. Reed had a small house built, made almost air-tight and with scarcely any ventilation. This building was known as the infected-clothing building, and was purposely so constructed as to exclude anything like efficient ventilation. It was placed on the opposite side of a small valley, about eighty yards from the infected mosquito building, and they were both about seventy-five yards distant from the camp proper. Both houses were provided with wire screen windows and double screen doors, so that mosquitoes could be kept without or within the building, as the experimenter might desire. In this building he placed material obtained from Las Animas, the yellow-fever hospital of the Health Department of Havana; mattresses on which yellow-fever patients had died, soiled by their excreta and discharges; sheets, pillows and pillow-cases stained with black vomit; the pajamas which patients had worn at the time of their death. It was Dr. Reed’s desire to have this material infected if it were possible to become infected in this way. Dr. John W. Ross, the superintendent of Las Animas Hospital, therefore gave the matter his personal attention, saw to the packing of this material in chests for transportation to Camp Lazear, and before the chests were closed, had basins of black vomit and other excreta from yellow-fever patients poured over the contents of the chest. If there were any possibility of such material becoming infected, infection certainly would have followed such procedure. Dr. Reed had this material opened up and spread out in the close room I have described. He called for volunteers to sleep in this room. Dr. R. P. Cook of the Army, and several soldiers quickly responded. These men put on the pajamas soiled as described, and slept on the mattresses and bed clothing soiled beyond description. For a period of twenty days they spent the nights in this building, but for the sake of general health were allowed to go out during the day. All the men remained perfectly well, and no case of yellow fever was developed from such exposure.