- Liebreich, Richard, 1830-19171
- Longet, F.-A. (Francois-Achille), 1811-18711
- Longmore, T. (Thomas), Sir, 1816-18951
- Louis, P. C. A. (Pierre Charles Alexandre), 1787-18721
- Lyall1
- Maisonneuve, I. G.1
- Malgaigne, J.-F. (Joseph-Francois), 1806-18651
- Martin, H. Newell (Henry Newell), 1848-18961
- McKenzie1
- McPherson, Samuel Dace1
- Mead, Richard, 1673-17541
- 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