Paul Ehrlich

Paul Ehrlich was born in Germany on 14 March 1854 and built his early career on staining techniques that let doctors see blood cells clearly for the first time, turning diagnosis of blood diseases from guesswork into science. His work on immunity earned him the 1908 Nobel Prize in Physiology or Medicine, shared with Élie Metchnikoff, and he developed critical methods for standardising antiserum against diphtheria. But the breakthrough that reset medicine came from his laboratory's discovery of arsphenamine - Salvarsan - the first antimicrobial drug and the first treatment that actually worked against syphilis. He died on 20 August 1915, leaving behind the Paul Ehrlich Institute, founded in his name in 1947, and a legacy so foundational he's been called the father of immunology.