Relation between the uterus and the ovaries in the pregnant hamster

In spite of many experimental investigations on numerous species, it still seems impossible to decide for how long the ovaries or the corpora lutea are necessary for maintaining pregnancy in mammals. As this problem has been thoroughly reviewed elsewhere (Asdell 1928; Parkes 1928; Klein 1934; Kehl 1934; Haterius 1935; Gros 1936), it is unnecessary to give a detailed survey of it here. Apparently mammals can be divided into two groups. In the first group, to which belong the rabbit, rat, mouse, and cow, ovariectomy or destruction of the corpora lutea always results in the termination of pregnancy and abortion at any stage of gestation. In the second group, on the contrary, it is possible to remove the corpora lutea or the whole ovaries a certain time after mating, without interfering with the normal progress of pregnancy and parturition; to this group belong the guinea-pig, cat, mare, and man. It follows that conclusions from experiments carried out on one species do not necessarily apply to another. It may be of interest therefore to describe results obtained on a species which has not hitherto been investigated; in the present paper we shall report experiments carried out on pregnancy in the Syrian golden hamster. 2. Material and technique The golden hamster, Cricetus ( Mesocricetus ) auratus Waterhouse, is a native of Syria, introduced into England in 1932; notes on its breeding and growth have been published by Bruce and Hindle (1934), who successfully bred the species. The animals used for the present experiments came from the stock kept at the National Institute for Medical Research, London, where most of our experiments were carried out. We have reared a colony of these hamsters at the Institut d’Histologie, Strasbourg, where the experimental series was completed.