1. BASTENIE, P. (1952), Lancet, ii, I97. BISHOP, P. VALE, M. W.
2. BROSTER, L. R. (1939), Brit. Y. Surg., 26, 925.
3. BROSTER, L. R., GARDINER HILL, H., and GREENFIELD, J. G. (1932), Brit. Y. Surg., 3g, 557-
4. BURROWS, H., COOK, J. W., and WARREN, F. L. (1936), J. Soc. Chem. Ind., 55, 031.
5. CALLOW, R. K. (1938), Proc. R. Soc. Med., 31, 841.