Several years ago, I received an announcement of a meeting in Germany of a “World Conference on Magic Bullets—Celebrating Paul Ehrlich’s 150th Birthday.” Who was Paul Ehrlich, what were his magic bullets, and what is the significance of Ehrlich’s work for the 21st century?

Paul Ehrlich was born in 1854 in Upper Silesia, then Germany. He studied medicine at the Universities of Breslau, Strasbourg, Freiburg, and Leipzig. In 1878, he obtained his doctorate of medicine. He then worked at a medical clinic in Berlin. In 1882, he became titular professor in Berlin and joined Robert Koch, the discoverer of the tubercle bacillus. The rest of his life Ehrlich spent in Frankfurt as director of a scientific institute where he received the Nobel Prize. He died in 1915 from a cerebral vascular accident. Ehrlich was a man obsessed by his work, burning the candle on both ends, but he was also gentle and caring, beloved by his staff and his family. Ehrlich was addicted to Havana cigars. Cigar smokers of today can only envy him; in Ehrlich’s time there was no embargo on imported cigars from Cuba...