1. Schrödinger, E., “What is Life?” (Cambridge University Press, 1944).
2. Lewis, G. N., “The Anatomy of Science” (Yale, 1926).
3. Needham, J., “Time: the Refreshing River” (London: Allen and Unwin, 1943).
4. J. Agric. Research, 59, 731, 749 (1939); 60, 765 (1940).
5. Northrop, J. Gen. Physiol., 16, 323 (1932). Anson and Mirsky, J. Gen. Physiol., 17, 399 (1934).