Lectures on the principles and practice of midwifery / by Edward William Murphy.

  • Murphy, Edward W. (Edward William), 1802-1877.
Date:
1862
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on the principles and practice of midwifery / by Edward William Murphy. Source: Wellcome Collection.

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    membrane. This layer is not thrown off at birth nor dispersed in the lochia, but remains attached to the inner uterine surface and forms the foundation of a new mucous membrane (Op. cit. p. 658). The Impregnated Ovum.—We have already described (p. 2.) the characters of the unimpregnated ovum, when about to leave the Graafian follicle—the vitelline membrane or zona pellucida, containing the yelk, within which are the germinal vesicle and germinal spot. Conception produces remarkable changes in the ovum while passing through the Fallopian tube. The yelk-sac becomes opaque, is covered by an albuminous fluid, and is thus ultimately converted into the Villous Chorion: the yelk shrinks so as to leave a space between it and the yelk-sac; the germinal vesicle and germinal spot disappear: and the yelk itself under- goes a change, by which a new membrane is ultimately formed. Bischoff has noticed in the rabbit an energetic rotatory move- ment in the whole yelk within the sac, attributed by him to the vibratile cilia. The yelk divides into two, four, eight spherical bodies, which multiply by subdivisions in a geometric progres- sion (t. e. by dichotomous segmentation) until they form a distinct granular coating surrounding a transparent fluid, the remains of the yelk (fig. 8). This is the Germinal Membrane, from which the embryo is formed. It is resolved into two coats or layers; Fig. 8.* the outer or tegumentary layer is called the serous coat ; the inner or visceral layer is called the mucous coat. The former completely envelopes the embryo and its organs, is reflected on * Fig. 8. Cleavage of the yelk. From Kirkcs' Physiology.
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