THE Yorkshire Post of July 9 directs attention to the recent isolation by Dr. H. D. Dakin, who is a former student of the Yorkshire College in Leeds, and West, of a substance effective in causing blood regeneration in pernicious anaemia; the paper describing the investigation is published in the Journal of Biological Chemistry, vol. 109, p. 489; 1935. The material is obtained from liver extract by precipitation with Reinecke acid; the precipitate is decomposed with the aid of dimethylaniline and the active principle afterwards purified by salting out with ammonium and magnesium sulphates and sodium chloride. It appears to be of protein nature: on hydrolysis, an aminohexose similar to glucosamine was isolated together with lysine, arginine, glycine, leucine, hydroxyproline and aspartic acid; cruder preparations also contain histidine, glutamic acid and possibly traces of phenylalanine. Pepsin hydrolyses it to a slight extent, erepsin completely though slowly. The compound produces a good reticulocyte response in cases of pernicious anaemia in doses of 80 mgm. when given by subcutaneous or intravenous injection. Dakin and West's paper indicates that a distinct advance has been made in the problem of isolating the liver principle active inperniciousanaemia.