. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. 120 COMPARATIVE PHYSIOLOGY. I- i: As a matter of fact, the pig, sheep, goat, cat, dog, and certain other animals may conceive when less than one year old; and the oow and the mare when under two years. At such periods these animals are not of course mature and should not be bred. OVUXiATIOM. In all vertebrates, at periods recurring with great regularity, the generative organs of
. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. 120 COMPARATIVE PHYSIOLOGY. I- i: As a matter of fact, the pig, sheep, goat, cat, dog, and certain other animals may conceive when less than one year old; and the oow and the mare when under two years. At such periods these animals are not of course mature and should not be bred. OVUXiATIOM. In all vertebrates, at periods recurring with great regularity, the generative organs of the female manifest unusual activity. This is oharaoterised by increased vascularity of the ovary and adjacent parts ; with other changes dependent on this, and that heightened nerve influence which, in the vertebrate, seems to be inseparable from all important functional changes. Ovulation is the maturation and discharge of ova from the Graafian folli- oles. The latter, reaching the exterior aone of the ovary, be- coming distended and thinned, burst externally and thiis free the ovum. The follicles being very vascular at this period, blood escapes, owing to this rupture, into the emptied capsule and clots ; and as a result of organization and subsequent degeneration undergoes a certain series of changes dependent on the condition of the ovary and related organs, which varies according as the ovum has been fertilized or not When fertilisation occiun the Graafian follicle undergoes changes of a more marked and lasting character, becoming a true corpus luteum of pregnancy. The number of Graafian follicles that ma- ture and the number of ripe ova that escape at about the same period varies, of course, with the species and the individual, and is not al- ways the same in the latter. In species that usually bear several young at a birth a corresponding number of ova must ^^^ be ripened and fertilized at about the same FicF. of ^^^ > while the reverse holds for those t
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Keywords: ., bookauthormillswes, bookcentury1800, bookdecade1890, bookyear1890
