How often does a map change the world? In 1854, one produced by Doctor John Snow, altered it forever.

In the world of the 1850s, cholera was believed to be spread by miasma in the air, germs were not yet understood and the sudden and serious outbreak of cholera in London’s Soho was a mystery.

So Snow did something data journalists often do now: he mapped the cases. The map essentially represented each death as a bar, and you can see them in the smaller image above.

It turned out that the water for the pump was polluted by sewage from a nearby cesspit where a baby’s nappy contaminated with cholera had been dumped. But he didn’t just produce a map; it was one part of a detailed statistical analysis.
(Source: The Guardian)

There is a lot of myth to unpack about John Snow, most of it debunkable by referring to the man’s own writings. But whatever the myths, the reality is that Snow made the jump from disease being caused by bad air to something in the water. And, in the case of the Hampstead outlier, his scientific method was brilliant.

In another life, I would have the biological prowess and detective cunning to be an epidemiologist.

In this one, I’ll stick to singing songs. 🙂