1. Ann. Rep. Brit. Emp. Cancer Campaign for 1949, pp. 39, 46.
2. Philips, F. S., J. Pharm. Exp. Ther., 99, 281 (1950).
3. Haddow, A. (unpublished work).
4. Rapoport, I. A., Dok. Akad. Nauk S.S.S.R., 60, 469 (1948).
5. Bird, M., paper read before the Genetical Society Symposium on Biochemical Genetics (London, 1950).