- Maisonneuve, I. G.1
- Malgaigne, J.-F. (Joseph-Francois), 1806-18651
- Martin, H. Newell (Henry Newell), 1848-18961
- McKenzie1
- McPherson, Samuel Dace1
- Meadows, Alfred, 1823-18871
- Medical equipment & supplies1
- Medical instruments1
- Microscope1
- Microscopes1
- Miller, James, 1812-18641
- Milne-Edwards, Henri, 1800-18851
- Morgan, Campbell de, 1811-18761
- Murchison, Charles, 1830-18791
- Nelaton, Auguste, 1807-18731
- Niemeyer1
- Nightingale, Florence, 1820-19101
- Nunnely, Thomas, 1809-18701
- Oppolzer, Johann, Ritter von, 1808-18711
- Owen, Richard, 1804-18921