The physiology of reproduction / by Francis H.A. Marshall, M.A. (Cantab.), D.Sc (Edin.) (Fellow of Christ's College, Cambridge, and University lecturer in Agricultural Physiology) ; with a preface by Professor E.A. Schäfer, Sc.D., LL.D., F.R.S. ; and contributions by William Cramer, Ph.D., D.Sc., and James Lochhead, M.A., M.D., B.Sc., F.R.C.S.E