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Ignaz Semmelweis

1818–1865

Hungarian doctor who worked in a Vienna maternity hospital.

What they got right

He compared death rates between two wards, spotted the difference, and tested a fix: chlorine handwashing cut deaths from childbed fever sharply in 1847.

Skill it shows

Evidence and sources

Practise this skill

Also: Numbers and chance

After the results of the chlorine washes convinced me of the true cause of childbed fever, I shared my opinion with the directors of several maternity hospitals so that I could free humanity, and as many people as possible, from this scourge as soon as possible.
'Der Meinungsunterschied zwischen mir und den englischen Aerzten über das Kindbettfieber' (1860), in Semmelweis' gesammelte Werke (1905), pp. 83–94Translation from German Source

Worth knowing

Most of his peers rejected the finding. He was slow to publish (1861) and attacked his critics bitterly, which hurt his case.

Try it yourself

Two groups get different results. Before blaming the obvious cause, list three other differences between the groups that could explain it.