Egg was rather below the middle height, with dark hair and a handsome well-formed face; the head of Peter the Great (in the picture of Peter and Catharine, which may be regarded as his best work, along with the Life and Death of Buckingham) was studied, but of course considerably modified, from his own countenance. He was manly, kind-hearted, pleasant, and very genial and serviceable among brother-artists; social and companionable, but holding mainly aloof from fashionable circles. As an actor he had uncommon talent. He appeared among Dickens’s company of amateurs in 1852 in Lord Lytton’s comedy Not so Bad as we Seem, and afterwards in Wilkie Collins’s Frozen Deep, playing the humorous part of Job Want.
EGG (O.E. aeg, cf. Ger. Ei, Swed. aegg, and prob. Gr. ὠόν, Lat. ovum), the female reproductive cell or ovum of animals, which gives rise generally only after fertilization to the young. The largest eggs are those of birds; and this because, to the minute essential portion of the egg, or germ, from which the young bird grows, there is added a large store of food-material—the yolk and white of the egg—destined to nourish the growing embryo while the whole is enclosed within a hard shell.
The relative sizes of eggs depend entirely on the amount of the food-yolk thus enclosed with the germ; while the form and texture of the outer envelope are determined by the nature of the environment to which the egg is exposed. Where the food material is infinitesimal in quantity the egg is either not extruded—the embryo being nourished by the maternal tissues,—or it passes out of the parental body and gives rise at once to a free-living organism or “larva” (see [Larval Forms]), as in the case of many lowly freshwater and marine animals. In such cases no “egg” in the usual sense of the term is produced.
The number of eggs periodically produced by any given individual depends on the risks of destruction to which they, and the young to which they give rise, are exposed: not more than a single egg being annually laid by some species, while with others the number may amount to millions.
Birds’ Eggs.—The egg of the bird affords, for general purposes, the readiest example of the modifications imposed on eggs by the external environment. Since it must be incubated by the warmth of the parent’s body, the outer envelope has taken the form of a hard shell for the protection of the growing chick from pressure, while the dyes which commonly colour the surface of this shell serve as a screen to hide it from egg-eating animals.
Carbonate of lime forms the principal constituent of this shell; but in addition phosphate of lime and magnesia are also present. In section, this shell will be found to be made up of three more or less distinct crystalline layers, traversed by vertical canals, whereby the shell is made porous so as to admit air to the developing chick.
The outermost, or third, layer of this shell often takes the form of a glaze, as of porcelain, as for example in the burnished egg of the ostrich: or it may assume the character of a thick, chalky layer as in some cuckoos (Guira, Crotophaga ani), cormorants, grebes and flamingoes: while in some birds as in the auks, gulls and tinamous, this outer layer is wanting; yet the tinamous have the most highly glazed eggs of all birds, the second layer of the shell developing a surface even more perfectly burnished than that formed by the outermost, third layer in the ostrich.
While the eggs of some birds have the shell so thin as to be translucent, e.g. kingfisher, others display considerable thickness, the maximum being reached in the egg of the extinct Aepyornis.
Though in shape differing but little from that of the familiar hen’s egg, certain well-marked modifications of form are yet to be met with. Thus the eggs of the plover are pear-shaped, of the sand-grouse more or less cylindrical, of the owls and titmice spherical and of the grebes biconical.