John Snow (1813-1858), British physician and anaesthetist. Snow treated victims of the first outbreak of cholera in Britain in 1831. He became convinced that contaminated water played a role in spreading the disease and recommended simple hygiene precautions. During further outbreaks in 1848 and 1854, he carried out investigations and proved the disease was caused by infected sewage contaminating wells and rivers. Snow also devised inhalation methods to deliver ether and chloroform anaesthetics to patients.