In the mid-19th century, Hungarian physician Ignaz Semmelweis had a radical idea:
Doctors should wash their hands.
Doesn't sound revolutionary? Well, it was at the time. Semmelweis noted the high mortality rates among women giving birth and had a crazy thought: it was the doctors themselves who introduced bacteria with their unwashed hands.
Soon after Semmelweis introduced the new practice, mortality rates in his department dropped by the factor of ten. Great, isn't it?
Not so much. Quickly, Semmelweis' practice became ridiculed. Washing of hands was called a "Jewish superstition". (The fact that Semmelweis wasn't Jewish didn't stop those claims.) He was kicked out of his hospital and committed to an insane asylum. There, he was beaten by the guards. The doctor who treated him did not wash his hands, Semmelweis got blood poisoning, and died at the age of 47.
You shouldn't dismiss Jewish superstitions so easily, goyim.