MITCHELL, John Kearsley, physician, born in Shepherdstown, Jefferson County, Virginia, 12 May, 1798 ; died in Philadelphia, Pennsylvania, 4 April, 1858. He was educated at Ayr and Edinburgh, Scotland, whither he had been sent at the age of eight, and on his return to this country studied medicine under Dr. Nathaniel Chapman, and was graduated at the medical department of the University of Pennsylvania in 1819. impaired health led to his accepting the appointment of ship surgeon, and he made three voyages to China and the East Indies, but in 1822 he settled in Philadelphia as a general practitioner. In 1824 he was called to lecture on the institutes of medicine and physiology at the Philadelphia medical institute, and in 1826 he became professor of chemistry in that institution. He was appointed to the chair of chemistry at the Franklin institute in 1833, and for five years thereafter delivered annually courses of lectures on chemistry applied to medicine and the arts. In 1841 he was chosen professor of the theory and practice of medicine in Jefferson medical college, which chair he held until his death. He was visiting physician to the Pennsylvania and City hospitals, and his services during seasons of pestilence were twice rewarded by municipal gifts. Dr. Mitchell prepared numerous professional papers which appeared in medical journals, and he was the author of several popular lectures on scientific subjects which were published in magazines. He was also the author of " Saint Helena," a poem " by a Yankee " (1821); "Indecision, a Tale of the Far West, and other Poems" (Philadelphia, 1839) ; " On the Wisdom, Goodness, and Power of God as illustrated in the Properties of Water" (1834); " On the Cryptogamous Origin of Malarious and Epidemic Fevers," which was a theoretical anticipation of the recent views as to the causes of many diseases (1849); and " Five Essays on Various Chemical and Medical Subjects" (1858), issued posthumously by his son.--His son, Silas Weir, physician, born in Philadelphia, Pennsylvania, 15 February, 1829, was educated at the University of Pennsylvania, but left during his senior year on account of illness, and was graduated at Jefferson medical college in 1850. Dr. Mitchell has attained a high reputation by his physiological researches, and early began the publication of papers on this subject. His first investigations were largely devoted to the chemical nature of the venom of serpents, and he issued through the Smithsonian institution "Researches on the Venom of the Rattlesnake," with an investigation of the anatomy and physiology of the organs concerned (1860), and, with George R. Moor-house, " Researches on the Anatomy and Physiology of Respiration in the Chelonia" (1863). During the civil war he had charge of the United States army hospital wards for diseases and injuries of the nervous system at Turner's lane hospital, Philadelphia, Pennsylvania, and was associated at that time in the preparation of valuable papers on "Reflex Paralysis," "Gunshot Wounds and other Injuries of Nerves," and " On Malingering, especially in regard to Simulation of Diseases of the Nervous Sys-tern." Subsequently he became president of the Philadelphia college of physicians. His papers treat chiefly of physiology, toxicology, and nervous diseases, on which subjects he is an acknowledged authority. He received the degree of LL. D. from Harvard in 1886, and in 1865 was elected to the National academy of sciences. He also holds similar relations to many other societies, including the British medical association. He has delivered various orations and addresses before medical faculties, and the titles of his papers exceed one hundred in number. Dr. Mitchell first turned his attention to fiction during the civil war, when he wrote "The Children's Hour," the sales of which were in aid of the Sanitary commission fair in Philadelphia. Subsequently he wrote short stories for the Children's hospital, and in 1880 published his first novel. Since then he has also produced a volume of verse. His works include "The Wonderful Stories of Fuzbuz the Fly, and Mother Grabem the Spider" (Philadelphia, 1867) ; "Wear and Tear, or Hints for the Overworked" (1871); "On Injuries of the Nerves and their Consequences" (1872) ; "Fat and Blood, and How to make Them" (1877); " Nurse and Patient, and Croup Cure" (1877); "Diseases of the Nervous System, especially of Women" (1881); "Hephzibah Guinness," "Thee and You," and "A Draft on the Bank of Spain" (1 vol., 1880) ; "The Hill of Stones, and other Poems" (1882): "In War-Time" (Boston, 1884); "Roland Blake" (1886); "A Masque and other Poems" (1887);" Proud Little Boy and other Tales out of Fairyland" (Philadelphia, 1888), and " Doctor and Patient, a Series of Essays" (Boston, 1888).