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Simon Flexner

Born 1863
Died 1946

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American pathologist and bacteriologist, born March 25, 1863, Louisville, Kentucky; died may 2, 1946, New York City.

Biography of Simon Flexner

Simon Flexner was the fourth child of Esther and Morris Flexner. He came from an educated Jewish family in Czechoslovakia who immigrated to Kentucky. She was born in Alsace, France. Starting as a peddler, Morris Flexner became a successful wholesale merchant.

The student years
Simon Flexner attended public school in Louisville and was apprenticed to a druggist who sent him to the Louisville College of Pharmacy, from which he was graduated in 1882. He then worked in his eldest brother’s drugstore and studied medicine at the University of Louisville, receiving the M.D. degree in 1889. Although the medical school then provided little opportunity for laboratory study, Flexner, acquired a microscope, with which he studied pathological tissues and made microscopic examinations for doctors who patronized the Flexner pharmacy.

In 1890, at the suggestion of his brother, the educator Abraham Flexner (1866-1959), Simon went to Baltimore to study pathology and bacteriology at the Johns Hopkins Hospital with William Henry Welch (1850-1934), who gave him a fellowship. He became associate professor of pathology in 1891 and in 1892, when the Johns Hopkins Medical School opened, Welch made him his first assistant in the department of pathology. At this time Flexner first became involved in the study of cerebrospinal meningitis. In 1893 he visited Europe, working with Friedrich von Recklinghausen (1833-1910) in Strassburg, and also visited Prague.

Professor of pathology
On his return Flexner became resident pathologist at the Johns Hopkins Hospital, teaching pathological anatomy 1895-1898. By 1898 he was appointed full professor of pathological anatomy at Johns Hopkins University. In 1899, following the acquisition of the Philippine Islands by the United States, Flexner and two medical students, one of them Llewellys Frederick Barker, spent several months in Manila studying health conditions. In 1899, during this stay, he isolated an organism that causes a prevalent from of dysentery. This Bacillus dysenteriae (now Shigella dysenteriae) is still commonly known as Flexner's bacillus. On his way to Manila, Flexner visited Japan and visited the Kitasato institute

Also in 1899, he was appointed professor of pathology at the University of Pennsylvania, where he organized an excellent staff, planned a new laboratory building, and carried out important researches on experimental dysentery, on experimental pancreatitis, and on immunological problems, especially with regard to haemolysis and agglutination. One of his associates was the brilliant young Japanese physician Hideyo Noguchi (1876-1928) who came from Japan inexperienced and penniless and found in Flexner a lifelong friend and guide.

When bubonic plague broke put in California in 1901, the federal government sent Flexner to San Francisco to study the epidemic. Within a month he and a few associates confirmed the presence of the plague bacillus and made a report to health authorities that aided them in eradicating the disease.

Rockefeller Institute
In 1901 John D(avison) Rockefeller (1839-1937) and his son John D. Rockefeller, Jr. (1874-1960), were planning the creation of the Rockefeller Institute for Medical research in New York City. Flexner, now thirty eight years old and beginning to be nationally known, was appointed to the institute’s board of scientific directors, which was composed of seven eminent medical men and headed by his friend and mentor William H. Welch. In 1902 Flexner was chosen to lead a department of pathology and bacteriology in the institute, and soon he established himself as head of the whole enterprise. Flexner was head of the institute from 1920 to 1935. Under Flexner’s leadership the Rockefeller Institute became the world’s leading centre for virus research.

Flexner brought together a strong group of investigators, including Hideyo Noguchi, Samuel James Meltzer (1851-1920), Phoebus Aaron Levene (1869-1940), Jacques Loeb (1859-1924), Eugene Lindsay Opie (1873-1971), Rufus I. Cole (1872-1966), and Francis Peuton Rous (1879-1970). Alexis Carrel (1873-1944) joined the staff in 1906. Flexner’s colleagues found him a man of exceedingly keen intelligence, with a reserved manner that concealed a sympathetic heart. He directed his staff with great skill, giving free rein to those who showed independent competence while guiding with a wise hand those who needed advice. His financial acumen impressed the astute patron of the institute, who showed his confidence by successive additions of funds.

In 1892, Simon Flexner began research on cerebrospinal meningitis, a meningococcal disease with an untreated mortality rate between 70 and 90 %. At the Rockefeller Institute, experimenting on Monkeys, he developed a promising serum treatment for the disease by 1903, which he used extensively during the epidemic of cerebrospinal meningitis that hit New York in 1906.

Also in 1906, the German physician Georg Jochmann (1874-1915), independent of Flexner, published on serodiagnostics and serum therapy for epidemic meningitis. Among 1300 patients Flexner reported in 1913, mortality was reduced to 31 percent. Among 169 children with meningococcal meningitis treated with intrathecal antiserum at Bellevue Hospital, New York, between 1928 and 1936, the outcome was even more favourable, with mortality of about 20 percent.

This serum remained the best treatment until the sulpha drugs were introduced in the late 1930's. The first sulpha drug, protonsil, was discovered by the German physician and chemist Gerhard Johannes Paul Domagk (1895-1964) in 1935. His discovery earned Domagk the Nobel Prize in Physiology or Medicine for 1939.

For several years, Flexner kept his serum under his close supervision, with the result that the Rockefeller Institute became the primary source for knowledge about meningitis and its treatment.

Infecting monkeys with poliomyelitis
Flexner led the research team that identified the virus causing poliomyelitis. In 1910, when poliomyelitis was epidemic in New York, Flexner and his assistants determined the way in which the virus is transmitted and showed that it enters the body through the nose, attacking the olfactory nerve. With Paul Aldin Lewis (1879-1929) he demonstrated that monkeys can be infected by administering poliomyelitis virus in the nasopharynx.

This success enabled the investigators to keep the virus alive in the laboratory and thus ultimately led to the preparation of protective vaccines in the 1950's by Albert Bruce Sabin (1906-1993) and Jonas Edward Salk (1914-1995).

The Rockefeller Institute, quite early in its history, came under strong attack from organizations opposed to the use of animals in experiments on the causes of disease. Flexner’s accomplishments in such work and his calm generalship made him a natural leader in the successful deterrence of these opponents.

A man for all seasons
Flexner’s medical and biographical accomplishments led to public service in various health fields, as chairman of the Public Health Commission of New York State, as medical consultant of the U.S. Army during World War I, and as member of the China Medical Board of the Rockefeller Foundation. In 1902 he succeeded William H. Welch as editor of the The Journal of Experimental Medicine.

His executive competence was recognized by trusteeships of the Rockefeller Foundation, the Carnegie Foundation for the Advancement of Teaching, and the Johns Hopkins University. A little known, but very important public service was his leadership in establishing fellowships of the National Research Council, provided by the Rockefeller Foundation, for promising young medical scientists.

Flexner was elected member of the American Philosophical Society in 1901, the National Academy of Sciences in 1908, and foreign member of the Royal Society in 1919.

In 1937-1938 Oxford University in England called him to its george Eastman professorship, at a time when his counsel was needed in the organization of medical professorships endowed by Lord Nuffield at Oxford's Radcliffe Infirmary. William Richard Morris Nuffield, Viscount, Baron Nuffield of Nuffield (1877-1963), was a British industrialist and philanthropist whose automobile manufacturing firm introduced the Morris cars.

In 1903 Flexner married Helen Whitall Thomas, member of a prominent Quaker Family of Baltimore. Helen's father played an important role in establishing The Johns Hopkins University and its Medical School, and Bryn Mawr College, of which her sister, Martha Carey Thomas (1857-1935), was president. She helped to expand Flexner's intellectual interests beyond the medical sciences, giving him an appreciation of literature and the arts. Of their two sons, William became a physicist and James Thomas (1908-2003) a writer and historian of American culture.

During his long career Flexner published several hundred scientific papers, lectures, and essays. At the age of seventy-eight he published jointly with his son James a notable biography, William H. Welch and the Heroic Age of American Medicine (New York, 1941). He quietly resigned the directorship of the Rockefeller Institute in 1935.

We thank Patrick Jucker-Kupper, Switzerland, and David Cox, for information submitted.

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