Referee's report by Henry Hallett Dale, on a paper 'Experimental studies on the differentiation of embryonic tissues growing in vivo and in vitro.—I. The development of the undifferentiated limb-bud (a) when subcutaneously grafted into the post-embryonic chick and (b) when cultivated in vitro' by T S P Strangeways and Honor Bridget Fell Sectional committee: Physiology Recommended for publication in Proceedings. The paper should be reduced to the conventional length of a Proceedings paper. [Published in Proceedings of the Royal Society B, 1926]. Endorsed on verso as received 14 October 1925. October 1925