Among diseases of man and beast, anthrax stands as one of the oldest known and certainly one of the most storied. (It is thought to be what Homer meant by the “burning plague” in the Iliad.) Once a common killer of grazing animals, it was also a lethal occupational hazard for humans who worked with infected hides and livestock. Yet the cause of anthrax remained a menacing enigma until well into the 19th century, when an unassuming German country doctor entered the picture to help name it and tame it.