Abstract
The transmissibility of the common cold has been frequently reported in the literature, notably by Dochez and his co-workers, and by Long and others. The following studies were undertaken to investigate this transmissibility under controlled conditions of environment. For this purpose an air conditioned room at the University Hospital was used. This room, which provides bed-space for 4 to 6 patients, is completely isolated from the outside atmosphere, being provided with its own air completely filtered and maintained at any temperature and humidity desired. It contains also an air lock, which permits ingress and egress with a minimum exchange of outside air, and a special lock, which permits service without any break in isolation of subjects. The air-lock, which receives the same air as is supplied to the room, contains the recording and controlling instruments and quarters for the experimental investigator, who was the only one allowed to enter or leave during the course of the experiment.
The room was maintained at a temperature of 70° to 71° F., dry bulb, and 60° to 62° F., wet bulb, which is a relative humidity of 55%. The air flow is approximately 66 cubic feet per minute, which gives a cooling power of 6 to 7 or within the normal limits of Leonard Hill. Barometric pressures were read daily and checked with those of the Weather Bureau. There is a very slight constant positive pressure due to the air being pumped into the room.
The experimental subjects were males between the ages of 21 and 40, who by history had 3 or more colds per year, the average being 5 to 6, and who had not had a cold within recent weeks.
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