Referee's report by Henry Stanley Raper, on two papers 'On conditions governing the form of the contraction of the gastrocnemius muscle of the frog and the sensitivity of the frog's heart to acetylcholine, Part I. The acetyl-choline-sterol balance' and 'On conditions governing the form of the contraction of the gastrocnemius muscle of the frog and the sensitivity of the frog's heart to acetylcholine, Part II. The thyroxine-adenylic acid balance' by G S Carter and Leslie William Mapson Sectional Committee: Physiology Not recommended for publication in the 'Proceedings of the Royal Society of London'. Reports as a letter to Archibald Vivian Hill. Outlines and criticises the arguments and experimental methods. Finds the data given to be insufficient for an independent researcher to repeat the experiments. Criticises the use and development of the substances. [Not published] Endorsed on verso as received 4 July 1936. 1 July 1936