Welch, William Henry, 1850–1934, American pathologist, b. Norfolk, Conn., grad. Yale (B.A., 1870), M.D. College of Physicians and Surgeons (now part of Columbia Univ., 1875). After studying abroad he taught (1879–84) at Bellevue Hospital Medical College, introducing laboratory methods of instruction. He was associated with Johns Hopkins, as professor of pathology (1884–1916), dean of the medical faculty (1893–98), director of the school of hygiene (1916–26), and professor of the history of medicine (1926–30). He was chairman of the board of the Rockefeller Institute for Medical Research (now Rockefeller Univ.) from 1901. His research includes studies of the Welch bacillus of gas gangrene and of embolism, thrombosis, and diphtheria.
See biographies by S. Flexner and J. T. Flexner (1941, repr. 1966) and D. Fleming (1954, repr. 1972).