Philippus Aureolus Theophrastus Bombast von Hohenheim, who called himself Paracelsus, stands at the cusp of medieval and modern times. A contemporary of Luther, an enemy of the medical establishment, a scourge of the universities, an alchemist, an army surgeon, and a radical theologian, he attracted myths even before he died. His fantastic journeys across Europe and beyond were said to be made on a magical white horse, and he was rumored to carry...