Titles
- Letter from Charles D. Hurd, Northwestern University to Michael Heidelberger1
- Letter from Charles R. Burnham to Barbara McClintock2
- Letter from Charles R. Drew [to the New Year]1
- Letter from Charles R. Drew to Lenore (Robbins) Drew3
- Letter from Charles R. Drew to his mother, Nora1
- Letter from Charles Seymour to Alan Gregg1
- Letter from Claude Forkner to Florence R. Sabin2
- Letter from Courtenay Crocker to Wilbur A. Sawyer1
- Letter from Curt Stern to Barbara McClintock1
- Letter from E. B. Fred to Edward L. Tatum1
- Letter from Edward L. Tatum to Nils Fries1
- Letter from Elvin A. Kabat to Michael Heidelberger2
- Letter from F. Elisabeth Crowell to Alan Gregg2
- Letter from F. W. Clement to Virginia Apgar1
- Letter from Florence B. Seibert to Florence R. Sabin2
- Letter from Florence R. Sabin to Austin Joyner1
- Letter from Florence R. Sabin to Catharine Macfarlane2
- Letter from Florence R. Sabin to Charles A. Doan2
- Letter from Florence R. Sabin to George W. Corner1
- Letter from Florence R. Sabin to Robert S. Cunningham1