Doctors, surgeons, and the ones who washed their hands before it was fashionable.

He grafted a human tooth onto a rooster's head to see what would happen. It grew.

He inoculated himself with a patient's discharge to settle a scientific question, and his reputation was so enormous that nobody checked his work for fifty-one years.

He built a small closet, filled it with the vomit of the dying, and sat inside breathing deeply — all to prove yellow fever wasn't contagious.

He died of the same infection, in the same place on his body, that he'd spent his life trying to prevent.

The French army once used a man who could swallow live puppies whole as a courier, hiding documents in his stomach.