This and the two following papers constitute part of the report upon a detailed investigation of the normal reproductive cycle in the ewe. Although the reproductive processes of mammals have been studied intensively during the past decade, it is to the small “laboratory” mammals that most workers have devoted their attention: little is known regarding reproduction in Ungulates except in relation to the cow, which has been studied by Hammond (1927) and others.
Certain aspects of reproduction in the ewe were studied by Marshall (1903) and Assheton (1906). During the last three years many minor papers on this subject have appeared but no comprehensive account is yet available, while, as will be shown in the following pages, many of the conclusions reached by previous workers were based upon examination of insufficient material.
It is hoped that this investigation will form the basis for fuller experimental study of reproductive phenomena in the ewe, particularly as they concern breeding practice, and that it will, stimulating interest in the sex physiology of the Ungulates, assist in laying the foundations for a more thorough understanding of the physiological mechanisms underlying reproduction in this group.