Titles
- Letter from Carl E. Buck to Louis Dublin1
- Letter from Catharine Macfarlane to Florence R. Sabin2
- Letter from Charles A. Doan to Florence R. Sabin2
- 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 Clarence Dennis to Austin Brues1
- Letter from Clarence Dennis to Frank S. Burch1
- Letter from Clarence Dennis to H. B. Zimmermann1
- 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 E. E. Huber to Lawrence Kolb1
- Letter from Edward L. Tatum to Nils Fries1
- Letter from Elvin A. Kabat to Michael Heidelberger2
- Letter from F. Elisabeth Crowell to Alan Gregg2