Florence Siebert

Florence Siebert (October 6, 1897&mdash;August 23, 1991) was an American scientist known for isolating a pure form of tuberculin used in the standard TB test. She is a member of the U.S. National Women's Hall of Fame.

Early life and education
Born in Easton, Pennsylvania, Siebert is said to have read biographies of famous scientists as a teenager which inspired her interest in science. As a child she contracted polio which left her walking with a limp, though the disability did not interfere with her life or work.

Siebert did her undergraduate work at Goucher College and earned her Ph.D. in biochemistry from Yale University. At Yale she studied the intravenous injection of milk proteins under the direction of Lafayette Mendel. She developed a method to prevent these proteins from being contaminated with bacteria.

Professional achievements and awards
In 1923 Siebert worked as a postdoctoral fellow at the University of Chicago. She was financed by the Porter Fellowship of the American Philosophical Society, an award that was competitive for both men and women.

Siebert served as an instructor in pathology from 1924-28 at the University of Chicago and was hired as an assistant professor in biochemistry in 1928. At the University of Chicaco she developed a method for purifying the crystalline tuberculin derivative under the supervision of Esmond R. Long. This purified protein derivative (PPD) was used in the standard TB test. The previous tuberculin derivative, Koch's substance, had produced false negative results in tuberculosis tests since the 1890's because of impurities in the material.

In 1932, she became assistant professor in biochemistry at the University of Pennsylvania at the Henry Phipps Institute and rose through the ranks to full professor and professor emeritus in 1959, when she retired. After her retirement she did volunteer work for many years in cancer research. Siebert received the Trudeau Medal from the National Tuberculosis Association in 1938, the Garvan Medal from the American Chemical Society in 1942, and an induction to the National Women's Hall of Fame in 1990.

Reference
Yost, Edna, American Women of Science, Frederick A. Stokes Company (Philadelphia and New York 1943)