From 1959 to ‘ 61 through cottage William wells it took 130 patients with tuberculosis. Their treatment was simultaneously part of the experiment: the air which they breathed, was in a purpose-built ventilation system and “fumigated” 72 cages with Guinea pigs. Half of the pigs were lucky: on the way, as it turned out, deadly flow of air in their room was an ultraviolet lamp. During the experiment among them not a sick one. The second group of animals, wells and colleagues left defenseless, and in this room the TB has picked up an average of three pigs per month. According to researchers, six wards with the patients were put into a room with pigs about 30 “infectious particles” per day.
In fact, the American scientist was not new: when the air is really considered a carrier of the infection (there is, for example, the name “malaria” means “bad air”). But after the work of Joseph Lister in the late nineteenth century, from the air and wove the real peddler of malware was phlegm, which is exhaled by the patient. The doctors sighed and focused on the protection of the liquid droplets.
In 1934, wells was offered to return to the idea of an invisible contagion. He estimated that even after heavy drops deposited on the surface in air can be pathogenic particles. They were impossible to touch and extremely hard to see (for this wells sprayed the spray in a brightly lit vessel), but they definitely existed — 63 tuberculosis infected Guinea pigs showed it to the world.
The researcher was one of the first who began to measure the transmissibility of infectious diseases in the particles. And began to collect data about how it is transmitted disease on the level of most of these particles: to evaluate required for infection the number of particles, their concentration in the air and with what speed they fly, settle and evaporate. In the course were intricate maze of air upon which the engineer drove the breath of patients, and then scraped off tubercle bacilli from the walls of blood vessels.
According to the estimates of wells, the fate of the man exhaled droplets can emerge in two ways. Some of them will fall down, obeying the laws of classical mechanics. The scientist believed that they will settle no further of two meters from the patient. Other drops, lighter, will remain hanging in the air, rapidly loses water. Steaming, they turn into “core droplets” (droplet nuclei) — concentrate the pathogen — and this suspension will last much longer. From the air of the experimental room, wells was able to isolate the tubercle Bacillus even a week after sprayed in there spray.