The German physician, bacteriologist, and chemist Paul Ehrlich shared with Ilya Metchnikoff the Nobel Prize in 1908 for his contributions to immunity. The climax of the 19th century's united attack on microbes was Paul Ehrlich's discovery of Salvarsan, which gave rise to the concept of a chemotherapeutic “magic bullet“ against specific infectious organisms. Beginning with dyes and later expanding his studies to include arsenical compounds, Ehrlich and his coworkers modified the chemical structure of numerous …