WILLIAMSON, Walter, physician, born in Newtown, Delaware County, Pennsylvania, 4 January, 1811; died in Philadelphia, Pennsylvania, 19 December, 1870. He was graduated in medicine at the University of Pennsylvania in 1833, and in 1848 was professor of obstetrics in the Homiaeopathic medical college of Pennsylvania. In 1852 he was transferred to the chair of materia medica and therapeutics, which he resigned in 1855 on account of failing health. He held the chair of obstetrics again in 1857-'9, and in 1860 was made professor emeritus, which post he continued to hold in Hahnemann medical college when the Homaeopathic college was merged in it. In 1869-'70 he lectured there on hygiene. Dr. Williamson was president of the American institute of homaeopathy in 1846 and of the state homaeopathic medical society in 1868. He was the author of " Instructions concerning the Diseases of Females, and the Conduct to be observed during Pregnancy, Labor, and Confinement" (Philadelphia, 1849), and "Diseases of Females and Children, and their Homaeopathic Treatment" (1854" revised ed. by George N. Epps, London, 1857), and has contributed to the " Homoeopathic Materia Medica of American Drug Provings " (Philadelphia, 1846), and to the "North American Journal of Homoeopathy," of which he was an assistant editor. He also edited Dr. Joseph Laurie's "Parents' Guide" (1849).