UNIVERSITY COLLEGELONDON-~GOWER STREET WCI DEPARTMENT OF ZOOLOGY Professor P, B. MEDAWAR Telephone EUSTON 7050 August 2nd 1957 Dear Dr Lederberg, I have just been obliged to write to Dr Hollaender to say that owing to "circumstances beyond my control" it will not after all be possible for me to visit the U.S. next year. The fact is that I am giving the Wayneflete Lectures at my old College in Oxford, and this is a major commitment for which I have to set aside every spare moment of my time. I have, iadeed, refused every temptation to go abroad next year, though none with such regret as the combined Gatlinburg-Wisconsin trip. I know that Billingham will be going to your conference, so that the immunology of transplantation will not be unrepresented. May I take this opportunity of wishing you all possible success in your new enterprise? I'm still hoping we shall meet some day! Yours sincerely, Dr Joshua Lederberg, Genetics Building, Uni ity of Wi in, ; ) “ University of Wisconsin Medecine U.S.A.