TECHNICAL COMMUNICATION NO. 15, issued by the Imperial Bureau of Animal Health (Rowett Institute, Aberdeen, 1944. 5s.), entitled "Minerals in Pasture, Deficiencies and Excesses in Relation to Animal Health", by Miss F. C. Russell, is a valuable review of this complex subject. The literature surveyed deals with diseases attributed or attributable to deficiencies of cobalt (bush sickness of New Zealand, pining in the United Kingdom, etc.); of copper (swayback in the United Kingdom and other countries, which is a disease of lambs with paralysis of the limbs, inco-ordination and demyelination of certain tracts of the spinal cord, which J. R. M. Innes (Vet, Record, 55, 369; 1943) has compared with certain rare diseases of man); of both copper and cobalt; and of potassium, sodium chlorine, iodine, phosphorus, caleium or magnesium (grass or lactation tetany). Other sections deal with diseases attributed or attributable to excesses of selenium, molybdenum, nitrate or manganese and with fluorosis and arsenical poisoning. A useful general summary completes the review, and the bibliographies of each section guide the reader to further study. The problems here discussed are difficult and are not for those who require circumscribed investigations which are certain to give results. Miss Russell has performed very well her difficult task of presenting the controversial literature about them, and everyone who is concerned with this kind of work will be grateful to her.