Referee's report by William Henry Power, on a paper 'Nitrification of sewage' by George Reid Sectional Committee: Physiology Not recommended for publication in the 'Proceedings of the Royal Society of London'. Should be modified for publication. Is surprised there is no reference to previous work on the subject, especially the work of Harriette Chick ['A study of the process of nitrification with reference to the purification of sewage', DOI: 10.1098/rspb.1906.0015 Vol.77 1906]. The current paper is argumentative. [Published in the 'Proceedings of the Royal Society of London'] Endorsed on verso as received 1 June 1906. 28 May 1906