1. Dickens, F., Biochem. J. (London) 27: 1141 (1933).
2. Rapkine, L., Comr pt. rend. soc. biol. 112: 790 (1933).
3. Young L. C. T. unpublishedt results.
4. Barrnett R. J., Science 116: 323 (1952).
5. Barron, E. S. G., Advances in Enzymol. 11: 201 (1951).