1. Nicolai, E., and Preston, R. D., Proc. Roy. Soc., B, 140, 244 (1952).
2. Preston, R. D., Wardrop, A. B., and Nicolai, E., Nature, 162, 957 (1948).
3. See, for example, Haas, P., Biochem. J., 29, 298 (1935). Challenger, F., and Simpson, M. I., J. Chem. Soc., 1591 (1948). Bywood, R., et al., Biochem. J., 48, 30 (1951). Percival, E. G. V., Quart. Rev. Chem. Soc., 3, 369 (1949).