There was a time in the not-too-distant past when hand-washing, even for doctors, wasn't considered part of basic hygiene. That is, until one man sounded the alarm.
You have to hand it to Ignaz Semmelweis, the 19th-century Hungarian doctor. For it was Semmelweis who determined, after studying maternity ward deaths, that it was hand-washing by doctors that could make all the difference between life and death.
Far from welcoming his insight, though, fellow doctors rejected it ... and Semmelweis went on to die in an insane asylum, of sepsis, the very thing he'd devoted himself to fighting.
Later generations came to recognize the truth of his discovery, and of course the need for thorough hand-washing has never been more important than now.
We're told that we should scrub our hands for at least 20 seconds ... that is roughly the time it takes to sing "Happy Birthday" from beginning to end, twice.