1. These series form part of a study of the influence of nutrition during pregnancy on the development of the lamb at birth. Details of this study are in preparation for publication.
2. Thomson, A. M., and Thomson, W., Brit. J. Nut., 2, 290 (1949).
3. Spiegelberg, O., “Die Dauer der Geburt”; “Lehrbuch der geburtshilfe”, 2 (1891); cited in Marshall's “Physiology of Reproduction”, 2, 509, ed. Parkes (Longmans, 1952).
4. Terrill, C. E., and Hazel, C. W., Amer. J. Vet. Res., 8, 66 (1947).