1. Gaddum, J. H., Ciba Foundation Symposium on Hypertension, London (J. and A. Churchill, Ltd., 1953).
2. Woolley, D. W., and Shaw, E., Science, 119, 587 (1954); Brit. Med. J., ii, 122 (1954).
3. Amin, A. H. T., Crawford, B. B., and Gaddum, J. H., International Physiological Congress, Montreal, 1953, p. 165. Twarog, B. M., and Page, J. H., Amer. J. Physiol., 175, 157 (1953).
4. Gaddum, J. H., J. Physiol., 121, 15P (1953).
5. See Sloane, B., and Lovett Doust, J. W., J. Ment. Sci., 100, 129 (1954), for a recent summary of work in this field.