DRYSDALE, Thomas Murray, physician, born in Philadelphia, Pennsylvania, 31 August 1831. After spending some time in a drugstore, in order to become familiar with pharmacy, he studied medicine in the Pennsylvania medical College, and under the instruction of Dr. Washington L. Atlee, whom he assisted in the chemical laboratory of the College, and whose daughter he married in 1857. He was graduated M. D. in 1852. He lectured on chemistry in the Wagner science institute in 1855, but resigned to devote himself to his practice in surgery and gynecology. ]n 1862 he delivered a course of lectures on the microscope in the Franklin institute. He also made valuable microscopical observations, and discovered and described the ovarian cell, which exists in ovarian tumors. He was one of the first to perform ovariotomy in Philadelphia. He was a delegate to the International medical congress in 1876, and one of the founders of the American gynecological society. He has published papers on rupture of the common duct of the liver, and the granular cell in ovarian fluid, "Dropsical Fluids of the Abdomen, being chap. xxiv of W. L. Atlee's work on "Diagnosis of Ovarian Tumors" (Philadelphia, 1873), and addresses on tracheotomy, and the use of chlorate of potassa in diphtheria and pseudomembranous croup.