Letter to John H. Musser, July 1901
Letter to Jennette Osler, December 16, 1872
Letter to James Tyson, August 6, 1884
Letter to Henry Vining Ogden, August 1, 1884(?)
Letter to William Osler, September 20, 1905
Letter to Arthur Thomson, January 10, 1904
Letter to Arthur Thomson, January 15, 1904
Letter to Arthur Thomson, January 27, 1904
Letter to Frederick Cheever Shattuck, August 28, 1903
Letter to Karl Friedrich Wenckebach, August 5, 1919