The 'sexual season' of mammals and the relation of the 'pro-oestrum' to menstruation / by Walter Heape.

  • Walter Heape
Date:
[1900]
Catalogue details

Licence: In copyright

Credit: The 'sexual season' of mammals and the relation of the 'pro-oestrum' to menstruation / by Walter Heape. 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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    season venders it necessary to discriminate clearly between them. The result of the foregoing may be summarised thus : when the male has not access to the female during the sexual season, or when insemination at that time does not result in the fertilisation of an ovum, pro-oestrum and oestrus are followed by metcestrum and, if the animal be polyoestrous, dioestrum is followed by another pro-oestrum, and such di- cestrous cycles continue so long as the sexual season lasts; whereas if the animal be moncestrous, or if the dioestrous cycles of the polyoestrous animal be ended, ancestrum follows, and persists until a new sexual season occurs. A few examples will render the foregoing somewhat more clear. Among moncestrous mammals is the wolf, which, in the wild state, experiences only one sexual season at a particular time each year; in her case pro-oestrum and oestrus are followed, when conception does not take place, by met- oestrum, and the whole of the remainder of the year is occupied by ancestrum. She therefore experiences a single anoestrous cycle each year. Another moncestrous animal is the domestic bitch ; but in her case, in the absence of gestation, the anoestrous cycle may recur two, three, or even four times each year. Among polyoestrous mammals the mare may be taken as an example; during a certain portion of the year, of variable extent, she undergoes a series of dioestrous cycles when she is not pregnant; this portion of the year is her sexual season; when it is over ancestrum occurs and lasts until the commencement of the same time the following }Tear. The human female, who is also a polyoestrous mammal, under certain circumstances has a continuous series of dioestrous cycles throughout the year when she is not preg- nant, and is thus subject to a sexual season during the whole of her reproductive period. (2) AAlien Reproduction does take place.—In this case the pro-oestrum is followed by oestrus, during which period insemination occurs and the ovum or ova are fer-
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