Simon Flexner
American scientist (1863-1946)
Simon Flexner (March 25, 1863 – May 2, 1946) was an American physician, scientist, administrator, and professor of experimental pathology at the University of Pennsylvania (1899–1903). He served as the first director of the Rockefeller Institute for Medical Research (1901–1935) (later developed as Rockefeller University) and a trustee of the Rockefeller Foundation. He was also a friend and adviser to John D. Rockefeller Jr.
Among Flexner's most important achievements are studies into poliomyelitis and the development of serum treatment for meningitis. Among his lab assistants were Hideyo Noguchi and Cornelius Rhoads, later directors of Memorial Hospital and the Sloan-Kettering Institute, respectively.
The bacteria species Shigella flexneri was named in recognition of Flexner. In addition, Flexner was the first to describe Flexner-Wintersteiner rosettes, a characteristic finding in retinoblastoma, a type of cancer.
Early life and career
Simon was born in Louisville, Kentucky, to Moritz (Morris) Flexner, a Jewish immigrant from Neumark, Bohemia, via several years in Strasbourg, France; and Ester from Roden, Germany. He was the fourth son of seven in a large family of nine children: Jacob, Henry, and Isadore; then Simon, followed by Bernard Flexner, Abraham Flexner, and Washington. The two sisters Mary and Gertrude were the youngest.
“Simon Flexner” enters the record as american scientist (1863-1946). Crown Archives preserves that source wording while asking what Simon, Flexner and American can confirm, complicate or overturn.
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Chronology provides the most reliable spine for this subject; interpretation should follow only after identities and dates are secure. The source revision retrieved here is dated Aug 29, 2026. The linked authority identifier is Q984262. The first chronological checks are 1863, 1946, 1899 and 1903.
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This entry incorporates text from “Simon Flexner” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.