1st Otto Krayer Lecture, Harvard Medical School, Boston, Massachusetts, USA, 10-17 March 1974 Katz gave a lecture titled 'Molecular action of acetylcholine at the neuromuscular junction' before going on to give the Murlin lecture in Rochester (E.22) during this trip to the USA. Correspondence with IH Goldberg and organisers re invitation, travel, arrangements and visas. 1973-1974