Copies and drafts of letters from Chain to Sir Edward Mellanby (Secretary, Medical Research Council), April 1944 and March 1945

Letter of 1944 urges the importance of fuller exchange of information between British and American scientists on penicillin synthesis.

Letter and drafts of 1945 are re publication of material on penicillin purification, and re Chain's wish to visit American 'to become acquainted with the latest developments in the deep fermentation technique, particularly as applied to the growth of actinomycetes'.