Ovulation and degeneration of ova in the rabbit / by Walter Heape ; (communicated by Adam Sedgwick).

  • Heape, Walter, 1855-1929.
Date:
1905
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Licence: In copyright

Credit: Ovulation and degeneration of ova in the rabbit / by Walter Heape ; (communicated by Adam Sedgwick). Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    {Rqninted from, the PROOEEDiNOSi©*: the Society, Vol. 7G.—is.] W Ovulation and Degeneration.-df Ova in the Rabbit. By Walter Heape, M.A., I’rimty College, Cambridge. (Communicated by Adam Sedgwick, F.K.S. Received March 6,—Read April 6, 1905.) It has long been held that ovulation invariably occurs in all animals at each period of oestrus. I have already shown (Nos. 13, 14, 15) that this is not necessarily true for menstruating animals. In other polyoestrous animals also there seems reason to believe that when coition is prevented during the first few recurrent oestrous periods, ovulation is interfered with during the subsequent periods, for conception is then much more uncertain than it is if coition occurs when the sexual season first appears. Moreover, among bats there is clear evidence that ovulation does not necessarily occur during oestrus (Nos. 2, 4, 5, 8), for the mature females are impregnated in the autumn and do not ovulate until later, probably the follovdng spring; although the young females, born in the late spring, do not copulate until the spring of the following year at the time when ovulation also occurs. With these facts before me I began, in 1894, investigations on the domestic rabbit. Over one hundred does were experimented on, and being kept in locked cages, of which I only had the key, certain errors so common with breeding experiments were avoided. The ovaries were preserved in various ways, and the histological results here given are determined from serial sections of which I have some 120 series. It was found that the domestic rabbit does not ovulate Until, approximately, 10 hours after copulation (cf. Nos. 1, 3). The doe rabbit only permits coition when undergoing oestrus, and if the male is withheld at that time the ripe ova in the ovary degenerate; they are not dehisced from the ovary. Neither stimulation of the vulva with electrodes, nor artificial insemination, nor subcutaneous injection of spermatozoa induced ovulation; moreover ovulation did not follow coition if from any cause a sufficient supply of blood to the ovaries was interfered with; while at the same time, provided this supply of blood was not interfered with, artificial stoppage of the progress of the spermatozoa from the vagina did not interfere with ovulation. The Oraafian Follicle and Ovum.—The follicle consists of a thick layer of epithelium, bounded on its outer edge by a basement membrane. Within, the ovum lies surrounded by its zona radiata. The structure is embedded in b