A doctor cut childbed fever deaths tenfold with hand-washing. Colleagues rejected him
In 1847, Ignaz Semmelweis found that maternity ward deaths fell tenfold once doctors washed their hands in chlorinated water between patients, especially after autopsies. Despite the stark evidence, fellow physicians dismissed the idea for decades, partly because they refused to believe a gentleman's hands could carry disease. Semmelweis died before germ theory vindicated him; his name now labels the reflex of rejecting evidence purely because it contradicts accepted belief.