Paul Ehrlich

From wikimedia​.org

Paul Ehrlich (1854–1915)

A German biologist and chemist who proposed the notion of specific affinity—that biological molecules work by virtue of binding other molecules with specificity.  Ehrlich synthesized chemicals with specific affinities for certain microbes, including those that cause sleeping sickness and syphilis. This discovery opened the door for later advances in chemotherapy. Ehrlich also coined the phrase “magic bullet” to describe specific cancer therapy.