Archive image from page 81 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana05todd Year: 1859 68 OVUM. gradually acquires the peculiar dry hardness which characterises it after the egg is laid. The view of H. Meckel that the animal basis of the shell is formed by the separation of a layer of the mucous membrane of the ute- rine part of the oviduct does not appear to be established. . During the time that the shell is forming, the distinction between the softer and thinner external albumen, and the more dense and deeper part, becomes more obvious, and, a
Archive image from page 81 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana05todd Year: 1859 68 OVUM. gradually acquires the peculiar dry hardness which characterises it after the egg is laid. The view of H. Meckel that the animal basis of the shell is formed by the separation of a layer of the mucous membrane of the ute- rine part of the oviduct does not appear to be established. . During the time that the shell is forming, the distinction between the softer and thinner external albumen, and the more dense and deeper part, becomes more obvious, and, at the same time, according to M. Coste, a cer- tain degree of liquefaction occurs in a layer of albumen immediately surrounding the yolk, which allows the latter body to float more freely within the superincumbent albumen. The egg remains in the uterine dilatation till it is about to be laid. The expulsion of it from this cavity through the narrow part of the tube, leading into the cloaca, requires very strong muscular contraction for its ac- complishment ; and, although the egg always descends in the oviduct, and usually lies in the uterus, with its narrow end downwards, both Purkinje and Von Baer state that they have sometimes seen its position inverted towards the end of the time of its residence there in consequence of the force of the mus- cular contractions of the wall of the oviduct. Ovarian ovum of birds ; uvulum ; yolk and its contents. — The yolk, yelk, or vitellus (Jaime, Fr. Duller, Germ.) consists in the newly laid egg of the external enclosing vitelline membrane, of the yolk substance, a mass of vesicular, cellular, and granular matter of va- rious structure, to which as a whole the membrane gives a subglobular form, and on the surface of this mass, below or within the vitelline membrane, and on that side of the yolk which naturally turns uppermost in the complete egg, the cicatricula, or embryo spot, a thin disc of organised cellular structure, in which, unde
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Keywords: 1850, 1859, anatomy, archive, book, bookauthor, bookdecade, bookpublisher, booksponsor, booksubject, bookyear, drawing, historical, history, illustration, image, london_sherwood_gilbert_and_piper, mblwhoi_library, page, physiology, picture, print, reference, todd_robert_bentley_1809_1860, vintage, zimmermann_a_albrecht_b_1860, zoology
