- McDowell, Joseph N. (Joseph Nash), 1805-18681
- McGown, Thompson.1
- McIlhenny, J. J.1
- McNair, Alexander H.1
- McVickar, J. A. (John Augustus), 1812-18921
- Medical College of Philadelphia.1
- Medical Convention of the State of Tennessee (1847 : Nashville, Tenn.)1
- Medical Institute of Philadelphia.2
- Medical Missionary Society in China.1
- Medical Society of Delaware.1
- Medical Society of Frederick County.1
- Medical Society of the County of Monroe.1
- Medical Society of the County of Rensselaer (N.Y.)1
- Medical Society of the State of New York (1807- )1
- Medical Society of the State of Pennsylvania.1
- Meigs, Charles D. (Charles Delucena), 1792-18695
- Meigs, Charles D. (Charles Delucena), 1792-1869, author1
- Meigs, J. Forsyth (John Forsyth), 1818-18821
- Mello, Joaquim Pedro de.1
- Mendenhall, George, 1814-18741