1. ACKROYD, J. F. (1949), Clin. Sci., 7, 249.
2. ADAMSON, H. G., and MACLEOD, J. M. H. (1926), Brit. 3. Derm., 38, I92.
3. CALNAN, C. D., and SARKANY, I. (1957), Trans. St. 3ohn's Hosp. Derm. Soc., 39, 28.
4. CALNAN, C. D., and SARKANY, I. (1958), Britj. Derm., 70, 435.
5. CHASE, M. W. (1954), Int. Arch. Allergy, 5, i63.