. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. OVUM. colour seems to be merely a uniform tinge of the outermost layer of calcareous matter.* The lining membrane of the shell is a peculiar fibrous, interwoven structure, depo- sited in laminae of some thickness and tough- ness, which is readily divided by tearing into two layers over the whole surface of the egg — an outer, thicker, and denser, adhering firmly to the inner surface of the shell; and an inner, thinner, smoother, and of finer texture, which may be easily withdrawn from the outer one, and which naturally s
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. OVUM. colour seems to be merely a uniform tinge of the outermost layer of calcareous matter.* The lining membrane of the shell is a peculiar fibrous, interwoven structure, depo- sited in laminae of some thickness and tough- ness, which is readily divided by tearing into two layers over the whole surface of the egg — an outer, thicker, and denser, adhering firmly to the inner surface of the shell; and an inner, thinner, smoother, and of finer texture, which may be easily withdrawn from the outer one, and which naturally separates from it at the air-space ; but both the outer and inner layers of this membrane may be torn into a number of thinner laminae, all agreeing in their minute structure. By microscopic examination, this membrane is found to consist of a closely-interwoven network of peculiar fibres, which are of va- rious sizes, generally between ^oVo*'1 and ^._i__th of an inch in diameter; the larger fre- quently branching into or giving off smaller fibres at acute angles, the sides rendered un- even by minute projections or knots upon them (not represented in the figure) ; the larger fibres are of a somewhat flattened or ribband-like form. The external layer of the membrane contains the largest fibres. These fibres appear to be analogous in their che- mical nature to those of the elastic yellow texture, not being soluble in strong acetic acid ; but they do not coil up in the manner of the elastic tissue {see Jig. 45. A). The parchment-like coverings of the eggs of serpents and lizards, which have no calca- reous shell, seem to be composed of a greater number of layers of the fibro-laminar texture now described. The albumen, or white of the egg, compre- hends several layers of glairy, albuminous, semifluid substance deposited round the yolk, the chalazae, or grandines, or twisted cords, and the condensed layer of albumen, forming a thin membranous investment immediately over the yolk m
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