- Ill, Edward J. (Edward Joseph), 1854-19421
- Ingals, E. Fletcher (Ephraim Fletcher), 1848-19183
- Inglis, David, 1850-1922 author1
- International Medical Congress 1887 : Washington, D.C.) author.6
- Iñigo, José, author1
- Irish, J. C. (John Carroll), 1843-1
- Irwin, Bernard John Dowling, 1830-1917 author1