The open schools of our time are the open wells of John Snow's time.
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https://www.ph.ucla.edu/epi/snow/snowcricketarticle.html
British doctor John Snow couldn’t convince other doctors and scientists that cholera, a deadly disease, was spread when people drank contaminated water until a mother washed her baby’s diaper in a town well in 1854 and touched off an epidemic that killed 616 people.
Dr. Snow, an obstetrician with an interest in many aspects of medical science, had long believed that water contaminated by sewage was the cause of cholera. Cholera is an intestinal disease than can cause death within hours after the first symptoms of vomiting or diarrhea. Snow published an article in 1849 outlining his theory, but doctors and scientists thought he was on the wrong track and stuck with the popular belief of the time that cholera was caused by breathing vapors or a “miasma in the atmosphere”.
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