1. Brambell, F. W. R., Transmission of Passive Immunity from Mother to Young, (North-Holland, Amsterdam and London, 1970).
2. Brambell, F. W. R., Lancet, ii, 1087 (1966).
3. Berken, A., and Benacceraf, B., J. exp. Med., 123, 119 (1966).
4. Parish, C. R., and Hayward, J. A., Proc. R. Soc., B 187, 47 (1974).
5. Jenkinson, E. J., and Billington, W. D., J. Reprod. Fert., 41, 403 (1974).