Referee's report by Cyril Norman Hinshelwood, on a paper 'Metabolic changes which form the basis of a microbiological assay of nicotinic acid' by H McIlwain Sectional Committee: Physiology Recommended for publication in the 'Proceedings of the Royal Society of London', if abridged to half its length. If the author wishes to keep the paper as it is, as a 'detailed and discursive treatment' it should be published elsewhere in a more specialist journal. [Published in the 'Proceedings of the Royal Society of London'] No received date. [1948]