When semmelweis  showed up for his new job in the maternity clinic at the General Hospital in Vienna, he  wanted to figure out why so many women in maternity wards were dying from puerperal fever (childbed fever).

What Semmelweis had discovered is something that still holds true today: Hand-washing is one of the most important tools in public health. It can keep kids from getting the flu, prevent the spread of disease and keep infections at bay.

For one thing, doctors were upset because Semmelweis' hypothesis made it look like they were the ones giving childbed fever to the women.

And Semmelweis was not very tactful. He publicly berated people who disagreed with him and made some influential enemies.

Eventually the doctors gave up the chlorine hand-washing, and Semmelweis — he lost his job.

Semmelweis kept trying to convince doctors in other parts of Europe to wash with chlorine, but no one would listen to him.