Brown to H H Dale, Campden Hill Court, Kensington, London Received today a copy of J H Burn's letter to Dale about vesicles in postganglionic sympathetic nerve terminals - sends quotation that Bernard Katz extracted from a Herter Lecture - wishes Burn would produce some evidence for his theory - has given up arguing with him in public. With copy of Burn's letter to Dale 14 April 1964