CURTIS, Josiah, physician, born in Wethersfield, Connecticut, in 1816. He was graduated at Yale in 1840, and soon afterward became principal of an academy in Salem, New Jersey, and later taught in Philadelphia, where he studied medicine, and in 1843 was graduated at Jefferson medical College. After spending a year in lecturing on physiology and public health, he settled for practice in Lowell, Massachusetts. In 1849 he removed to Boston, and between 1850 and 1855 twice visited Europe for the purpose of studying the sanitary condition of the large cities. In 1861 he was called to Washington to superintend the mortality statistics of the U. S. census of 1860. He there entered the army, and remained with it until 1865, when he took up his residence in Knoxville, Kentucky. In 1872 Dr. Curtis filled the place of surgeon, microscopist, and naturalist to the U. S. geological survey, and in 1873 became chief medical officer of the U. S. Indian service. He has published numerous articles on ventilation and kindred subjects, and is the author of a report on the "Hygiene of Massachusetts " (1849), and earlier reports to the Massachusetts legislature on the registration of births, marriages, and deaths. He is noted as the discoverer of collodion.