On the occurrence of the œstrous cycle after X-ray sterilisation part II.—Irradiation at or before birth

Abstract

The main series of animals was irradiated immediately after birth. A smaller series, of which only 1 sterilized animal survived, was irradiated as fetuses in utero. In the 2 series, 63 periods of estrous were observed in 24 sterilized [female] ; 9 of these animals, however, showed only 6 periods in all, and these animals were found to have ovaries composed almost entirely of luteal-like tissue, and since the absence of the estrous cycle can not be directly ascribed to the absence of follicles, it is supposed that its absence in these animals was due to the direct mechancal inactivation of the normal sterilized ovary by the destructive development of this luteal-liie tissue. The observation of 57 periods of estrous in the other 15 sterilized [female], whose ovaries possessed neither graafian follicles nor corpora lutea vera, is direct supplementary evidence that neither of these structures is essential for the regulation of the cyclic phenomena which constitute the estrous cycle of the accessory reproductive organs, and taken in conjunction with previous results seems to prove this point conclusively. The light thrown by these experiments on the regulation of the normal estrous cycle is discussed.