1. Marriner, G. R., Trans. Proc. N.Z. Inst., 42, 176 (1910).
2. Briggs, M. H., Nature, 191, 1137 (1961).
3. Claus, G., and Nagy, B., Nature, 192, 594 (1961).
4. Wilson, A. T., Nature, 188, 1007 (1960).
5. Needham, A. E., Quart. Rev. Biol., 34, 189 (1959). Oparin, A. I., Origin of Life on the Earth (Academic Press, New York, 1957).