Castle, William B. (William Bosworth), 1897-

Alternative names
Birth 1897-10-21
Death 1990-08-09

Biographical notes:


From the description of Reminiscences of William Castle: oral history, 1987. (Columbia University In the City of New York). WorldCat record id: 122441462

William Bosworth Castle (1897-1990), MD, 1921, Harvard Medical School, was George Richards Minot Professor of Medicine and Francis Weld Peabody Faculty Professor of Medicine, and directed the Harvard Medical Services at Boston City Hospital from 1940 to 1963. Castle's research focused on blood diseases including pernicious anemia and sickle cell anemia.

From the description of Papers, 1921-1987. (Harvard University). WorldCat record id: 78631249

William B. Castle (1897-1990), M.D., 1921, Harvard Medical School, Boston, Massachusetts, was a leading hematologist, discovering gastric intrinsic factor and how its absence in human digestion leads to pernicious anemia. Castle served as Director of the Thorndike Memorial Laboratory at Boston City Hospital from 1948 to 1968 and as Professor of Medicine (1937-1957), George Richards Minot Professor (1957-1963), and Francis Weld Peabody Faculty Professor (1963-1968) at Harvard Medical School. After his retirement from Harvard Medical School in 1968, he held the position of Distinguished Physician in the Veterans Administration (VA) Hospital until his death in 1990.

William Bosworth Castle was born in Cambridge, Massachusetts on 21 October 1897 to William E. Castle (1867-1962), a professor of zoology at Harvard University, and Clara Sears Bosworth Castle (1870-1940). Castle attended Browne and Nicholas School in Cambridge, Massachusetts, and in 1914, entered Harvard College. At the end of his third year, Castle enrolled at Harvard Medical School and received his M.D. in 1921 without earning a bachelor’s degree, though he was elected to Phi Beta Kappa and Alpha Omega Alpha. Castle completed his internship with Massachusetts General Hospital, Boston, from 1921 to 1923.

Castle began his career at Boston City Hospital in Harvard Medical School's Thorndike Memorial Laboratory. It was there, in 1928, that he discovered the cause of pernicious anemia, then a fatal disease. Through experimentation, primarily on himself, Castle discovered that absence of the intrinsic factor in digestion did not allow patients to absorb much needed iron. Through this research, Castle also discovered that vitamin B-12 is a key ingredient for the treatment of pernicious anemia. In 1931, Castle led an expedition to Puerto Rico where he studied the diseases tropic sprue and anemia as Director of the Rockefeller Foundation Commission for the Study of Anemia in Puerto Rico. There, with Cornelius P. (Dusty) Rhoads, he introduced a new treatment for tropical sprue based upon his initial discoveries with iron and liver extract in pernicious anemia cases. In 1948, Castle became the third director of the Thorndike Memorial Laboratory, and in 1957, he was appointed to the George Richards Minot Professorship at Harvard Medical School; in 1962, a professorship was named in his honor. In 1963, Castle became the first Francis Weld Peabody Faculty Professor of Medicine, a position he held until his official retirement in 1968. That year, he became Distinguished Physician in the West Roxbury Veterans Administration Hospital, a position which he held until his death in 1990.

Castle received Honorary Degrees from Yale University, the University of Utrecht, the University of Chicago, Boston College, and the University of Pennsylvania. He was a Fellow of The American Academy of Arts and Sciences, as well as a Member of the National Academy of Science. In 1933, Castle married Louise Muller and moved with her to Brookline, Massachusetts. They had two children, Anne Castle Morris and William Rogers Castle. William B. Castle died on 9 August 1990.

From the guide to the William B. Castle papers, 1889-1991 (inclusive), 1925-1989 (bulk)., (Francis A. Countway Library of Medicine. Center for the History of Medicine.)


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Ark ID:


  • Hematologic Diseases
  • Hematology
  • Physicians--Interview
  • Blood--Diseases
  • Pernicious anemia


  • Hematologists


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