The University of Chicago CHICAGO 37, ILLINOIS Institute of Radiobiclogy and Biopbysics 6200 Drexel Avenue December 7, 1949 Dr. Joshua Lederberg Department of Genetics University of Wisconsin Madison 6, Wisconsin Dear Dr. Lederberg: When returning home on the train and going over our conversation, I was a little troubled about what I had said to you about Leo. As I recall, I said, “You know how Leo does things, in a sort of underhanded way.” I did not mean to speak dispar- agingly at all, and I undoubtedly should have used some such word as indirect, devious, or unconventional, I hope that you understand, I want to take this opportunity to thank you for the trouble you took to show me the campus and Madison. I am looking forward to seeing you on the 19th and 20th, Yours very sincerely, Director