Titles
- Letter from MacGregor Instrument Company to Michael E. DeBakey and William H. Gillentine2
- Letter from Marguerite Stein to Florence R. Sabin4
- Letter from Marjory Stephenson to Walter Fletcher1
- Letter from Max Delbruck, California Institute of Technology to Michael Heidelberger1
- Letter from Michael E. DeBakey and William H. Gillentine to MacGregor Instrument Company1
- Letter from Michael E. DeBakey and William H. Gillentine to O. O. R. Schwidetzky1
- Letter from Michael E. DeBakey to his father, Shaker4
- Letter from Michael E. DeBakey to his parents1
- Letter from Numa P. G. Adams to Charles R. Drew1
- Letter from O. O. R. Schwidetzky to Michael E. DeBakey5
- Letter from Oswald T. Avery to Fred E. Wright, National Academy of Sciences1
- Letter from Oswald T. Avery to Michael Heidelberger1
- Letter from Oswald T. Avery to Minnie Wandell2
- Letter from Oswald T. Avery to Roy Avery1
- Letter from Oswald T. Avery to Roy and Catherine Avery1
- Letter from Owen H. Wangensteen to Harry P. Ritchie1
- Letter from Percival Hartley, Medical Research Council of Great Britain to Michael Heidelberger1
- Letter from Peyton Rous to Oswald T. Avery1
- Letter from Ralph M. Waters to Virginia Apgar4
- Letter from Raymond Fosdick to Alan Gregg1