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

  • Walter Heape
Date:
1905
Catalogue details

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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    between them. It appears obvious that thus the supply of ovarian nutriment is stopped. About nine hours after copulation maturation of the ovum takes place and two polar bodies are rapidly formed. It is of interest to notice that maturation does not occur until after the supply of nutriment to the ovum is cut off, for in this particular it appears probable that the formation of polar bodies takes place under conditions of nutriment essentially diflerent from those which prevail during segmentation. Omdation,—About 10 hours after copulation the G-raafian vesicle ruptures through the attenuated wall which projects on the surface of the ovary. The ovum, entirely freed from the discus proligerus cells, is shot out into the infundibulum which now closely invests the ovary. Once freed from the ovary the mature ovum is incapable of assimilating niitriment unless it be fertilised ; if from any cause fertilisation is not effected the ovum quickly dies, although it i/bathed in the nutrient material supplied by the maternal tissues; ova thus degenerating are, from time to time, to be seen in the fallopian tubes. It is necessary then, in the case of rabbits at any rate, that spermatozoa should be present in the fallopian tubes, and 1 find tliat as a rule they are to be found at the top of the uterus horn two hours after copulation and close to the infundibulum, if not actually within its folds, four hours after copulation. In those animals in which the ovum does not undergo maturation in the ovary, the presence of spermatozoa at the top of the fallopian tube is not necessary. In the mouse, for instance (No. 29), when the ovum is dehisced from the ovary it is not free from discus cells, and the polar body may be formed during its passage down the fallopian tube. Kecently it has been shown (No. 23) that in the ferret ovulation does not take place without previous copulation, the same is also said of the pig and sheep (No. 11, cf. also. No. 22) and guinea-pig (No. 26), and I suspect it will also be found to be true for other animals. It is interesting to note that O ovulation in the frog takes place only when a certain stage of maturation is reached (No. 24). The fact that maturation of the ovum does not occur until after copulation has taken place affects fundamentally the results of various experiments which have been made on artificial fertilisation of rabbit’s ova (Nos. 10, 25, 28). The Rupture of the Follicle and the Corpus Luteum.—Tlie cause which induces the rupture of the Graafian vesicle is obscure. Immediately before rupture the wall of the distended follicle where it projects on the surface of the ovary is very thin, and is covered by a thin layer of the tunic of the ovary. The congested vessels which surround the follicle are present also between the follicle and the tunic of the ovary in this distended portion.
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