1. Lohmann, Naturwiss., 17, 624 (1929). Fiske and Subbarow, Science, 70, 381 (1929).
2. Biochem. Z., 233, 460 (1931); 254, 381 (1932); 282, 120 (1935).
3. Nature, 155, 695 (1945).
4. Cf. Todd, J. Chem. Soc., 647 (1946) for general review.
5. Davoll, Lythgoe and Todd, J. Chem. Soc. (in the press).