Jayant RadhakrishnanChicago, Illinois, United States Pierre-Fidèle Bretonneau described diphtheria as a distinct entity in 1821.1 He named it after the Greek word for leather2 because of the thick gray membrane that forms in the throat. Physicians before him, starting with Hippocrates, considered asphyxiating diseases as a group that also included tonsillitis, croup, and malignant angina.…