John Snow (1813–1858) was a pioneering British physician and a founding father of modern epidemiology and anesthesia. He famously identified contaminated water, rather than air, as the source of the 1854 London cholera outbreak by mapping cases, and he served as anesthesiologist to Queen Victoria. John Snow (1813–1858) was a pioneering British physician and a founding father of modern epidemiology and anesthesia. He famously identified contaminated water, rather than air, as the source of the 1854 London cholera outbreak by mapping cases, and he served as anesthesiologist to Queen Victoria.