Referee's report by David Keilin, on a paper 'A study of the physical and chemical properties of the insect cuticle' by Gottfried Fraenkel and K M Rudall Sectional committee: Physiology Recommended for publication in Proceedings. The explanation of hardening the chitin differs from that developed in the paper of Pryor before. They should perhaps withhold the paper until Pryor's has been published. No reference is made in the text to Meyer and Pankow. More details about indexing should be added to the explanation. [Published in Proceedings of the Royal Society A, 1940]. Endorsed on verso as received 11 February 1940. February 1940