1. Fleisch, H., Russell, R. G. G., and Straumann, F., Nature, 212, 901 (1966).
2. Russell, R. G. G., and Fleisch, H., Clin. Orthop. (in the press).
3. Cartier, P., Bull. Soc. Chim. Biol., 39, 169 (1957).
4. Cartier, P., Bull. Soc. Chim. Biol., 41, 573 (1959).
5. Perkins, H. R., and Walker, P. G., J. Bone Joint Surg., 408, 333 (1958).