Referee's report by David Keilin, on a paper 'A natural factor catalysing reduction of methamoglobin by isolated chloroplasts' by H E Davenport, Robert Hill and Frederick Robert Whatley Sectional committee: Physiology Paper reference code: B48 Recommended for publication in the Proceedings. Keilin writes: 'A valuable contribution to the study of the mechanism of O2 evolution during photosynthesis'. [Published in Proceedings B, 1952]. Date received not given. 7 September 1951