Simon Flexner (a brother of Abraham Flexner) was a distinguished pathologist who served as the first director of the Rockefeller Institute for Medical Research (RIMR) and as one of the original Rockefeller Foundation (RF) trustees.
Flexner was born in Louisville, Kentucky, in 1863. He received his medical degree from the University of Louisville Medical School in 1889 before pursuing a post-graduate fellowship at Johns Hopkins University. There he developed a particular interest in the fields of pathology and bacteriology and the study of meningitis. Following his fellowship, Flexner accepted an assistant professorship in pathology at Johns Hopkins. In 1895 he was promoted to associate professor and also elected to the American College of Physicians.
Flexner left Johns Hopkins for a position at the University of Pennsylvania in 1899. By 1901 he was also working at the Philadelphia Hospital and was appointed director of the University of Pennsylvania’s Ayer Clinical Laboratory.
In 1902 he left Philadelphia to become the first director of the newly established RIMR in New York City. Flexner was instrumental in shaping the research goals and priorities for the new institution, and he appointed an impressive staff of researchers. His own research also flourished at the Institute. It was at RIMR that Flexner developed an antiserum treatment for meningitis and conducted important research on polio.
During World War I, Flexner lent his services to the Army Medical Corps and created a training program for medical officers. He retired from the RIMR in 1935 and in 1937 he left the United States to take up a visiting professorship at Oxford University.
From the founding of the RF in 1913 until 1930, Flexner was a guiding force on the Foundation’s Board of Trustees. He was also a board member of the Johns Hopkins University School of Medicine, a chairman of the Public Health Council of New York State and an advisor to the American Red Cross.
Throughout his career Flexner was bestowed with many honorary memberships and prizes for his work in the medical sciences. He contributed to more than 350 articles in the fields of pathology and bacteriology.
Simon Flexner died of a heart attack at age 83 in 1946. His papers can be found at the American Philosophical Society, the Becker Medical Library at Washington University School of Medicine, and the Rockefeller Archive Center (RAC).