1. Code, C. F., Amer. J. Physiol., 127, 78 (1939).
2. Ojers, G., Holmes, A. C., and Dragstedt, A. C., J. Pharmacol., 73, 33 (1941).
3. Humphrey, J. H., and Jaques, R., J. Physiol., 124, 305 (1954).
4. Brocklehurst, W. E., and Lahiri, S. C., J. Physiol., 160, 15 (1962).
5. Brocklehurst, W. E., J. Physiol., 151, 416 (1960).