Washing your hands. It's one of the easiest and most effective things you can do to protect yourself from the coronavirus, the flu, and other respiratory illnesses. But there was a time when that wasn't so obvious. Dana Tulodziecki, a professor at Purdue University, tells the story of Ignaz Semmelweis, the scientist who's credited with discovering the importance of handwashing. We'll hear how he figured it out and why there's more to the story. (Encore episode)Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy