_Kansas State Coleg. Manhattan, Kansas Department of Bacteriology 11 December 1956 Professor Joshua Lederberg Department of Genetics University of Wisconsin Madison 6, Wisconsin Dear Jogh: I am indeed flattered that any of our work would be of interest to you. You are certainly welcome to use any of our findings or techniques, Carl Kirchner, a graduate student in our depart ment, is now working on the versene effects, I will have hin send you his additional results and procedures, We actually have little that is mew on the K12, since Carl is now working on the versene effect on transduction in S. typhimuriun. Many thanks for your comments on the Hirota paper in Nature, I had read it but I had not repeated the experiments, Best personal regards. Sincerely, Od A. Elsenstark Associate Professor 4