March 15, 2013, marks the 200th birthday of John Snow, the singular genius who created the modern science of epidemiology. Without fear of historical hyperbole, the occasion merits a global pause of reflection and honor.
Born in York, England, John Snow chose a life in medicine at a relatively young age. At 16, he began an apprenticeship under William Hardcastle, a surgeon who practiced in Newcastle-upon-Tyne. A few years later, in 1831, Snow first encountered cholera, which entered Newcastle via the seaport of Sunderland and decimated his town.