Paul Ehrlich

Paul Ehrlich (14 March 1854 – 20 August 1915) was a German physician and scientist of Jewish descent whose research founded key principles in hematology, immunology, and chemotherapy.

Ehrlich's early work involved selective staining of blood cells with dyes, enabling the classification of leukocytes and the identification of mast cells, which advanced understanding of cellular pathology and immune responses. He developed the side-chain theory of immunity, positing that cells produce receptor-like side chains that bind antigens and trigger antibody production, a concept central to modern immunology.

Paul Ehrlich was born on March 14, 1854, in Strehlen, a small town in the Prussian province of Lower Silesia (now Strzelin, Poland), to a prosperous Jewish family that had resided in the region since the 18th century. His father, Ismar Ehrlich, operated a successful liqueur distillery and served as the local royal lottery collector, providing the family with financial stability and social standing. Ehrlich's mother, Rosa (née Weigert), hailed from a scholarly background; her nephew, Carl Weigert, was a prominent pathologist whose work later influenced Ehrlich's research interests.