In the summer of 1854 in order to test his theory Snow carried out what become known as the Grand Experiment, tramping the streets of South London while the country was in the grip of its third cholera epidemic, knocking on doors and asking which of two water companies the householder used. (via John Snow and cholera: how myth helped secure his place in history | OUPblog)

In the summer of 1854 in order to test his theory Snow carried out what become known as the Grand Experiment, tramping the streets of South London while the country was in the grip of its third cholera epidemic, knocking on doors and asking which of two water companies the householder used. (via John Snow and cholera: how myth helped secure his place in history | OUPblog)