Letter to Karl Friedrich Wenckebach, March 30, 1910
Letter to Mabel Brewster, April 2, 1910
Letter to Henry Barton Jacobs, April 21, 1910
Letter to Hunter Robb, April 27, 1910
Letter to Karl Friedrich Wenckebach, May 7, 1910
Letter to Henry Barton Jacobs, May 9, 1910
Letter to Maude E. Abbott, May 2, 1910
Letter to Maude E. Abbott, May 14, 1910
Letter to Sigmund Adolphus Knopf, May 23, 1910
Letter to Edward F. Milburn, June 18, 1910