THE EGG
“When moistening your slices of bread with egg, has it ever occurred to
you to examine a little the structure of what furnishes your repast? I
think not. To-day I am going to tell you something about this: I will
show you in detail this wonder called an egg.
“First, let us examine the shell. In hens’ eggs it is all white, as
also in those of ducks and geese. Turkeys’ eggs are speckled with a
multitude of little pale red spots. But it is particularly the eggs of
undomesticated birds that are remarkable for their coloring. There are
sky-blue ones, such as those of certain blackbirds; rose color for
certain warblers; and somber green with a tinge of bronze is found, for
example, in the eggs of the nightingale. The coloring is sometimes
uniform, sometimes enhanced by darker spots, or by a haphazard
sprinkling of pigment, or by odd markings resembling some sort of
illegible handwriting. Many rapacious birds, chiefly those of the sea,
lay eggs with large fawn-colored spots that make them look like the
pelt of a leopard. I will not dwell longer on this subject, interesting
though it may be, as in telling you the story of the auxiliary birds I
have already described the eggs of the principal kinds.”
“I have taken care,” interposed Jules, “to remember the curious variety
of coloring that eggs have. I recall very distinctly the nightingale’s,
green like an olive; the goldfinch’s, spotted with reddish brown,
especially at the larger end; the crow’s, bluish green with brown
spots; and so many others that I hesitate to say which are my
favorites, so nearly equal are they in beauty.”
“Let us learn now about the nature of the shell,” his uncle continued.
“The substance of the shell is, in the hen’s egg, as white as marble;
its own color not being disguised by any foreign pigment. This pure
white and its other characteristics, hardness and clean fracture, do
they not tell you of what substance the shell is composed?”
“Either appearances deceive me greatly,” answered Louis, “or the shell
is simply made of stone.”
“Yes, my friend, it is indeed of stone, but stone selected with
exquisite care and refined as it were, in the bird’s body.
“In its nature the eggshell does not differ from common building-stone;
or rather, on account of its extreme purity, it does not differ from
the chalk that you use on the blackboard, or from the magnificent white
marble that the sculptor seeks for the masterpieces of his chisel.
Building-stone, marble, and chalk are at bottom the same substance,
which is called lime, limestone, or carbonate of lime. The differences,
great as they may be, have to do with the state of purity and degree of
consistency. That which building-stone contains in a state of impurity
from other ingredients is contained also in white marble and chalk, but
free from any admixture. Thus in its nature the eggshell is identical
with chalk and marble, harder than the first, less hard than the
second, being between the two in an intermediate state of pure lime. To
clothe the egg, therefore, with a solid envelope, the hen and all birds
without exception use the same material as the sculptor works with in
his studio and the scholar uses on the blackboard.
“Now, no animal creates matter; none makes its body, with all that
comes from it, out of nothing. The bird does not find within itself the
material for the eggshell; it gets it from outside with its food. Amid
the grain that is thrown to her the hen finds little bits of stone left
there through imperfect cleaning; she swallows them without hesitation,
knowing full well, however, that they are little stones and not kernels
of wheat. That is not enough; you will see her all day long scratching
and pecking here and there in the poultry-yard. Now and then she digs
up some worm, her great delicacy, and from time to time some fragment
of limestone, which she turns to account with as much satisfaction as
if she had found a plump insect.”
“I have often seen hens swallowing little stones like that,” remarked
Emile. “I thought it was all their own carelessness or gluttonous
haste, but now I begin to suspect the truth. Would not those little
stones be useful in making the eggshell?”
“You are right, my little friend. The particles of lime swallowed with
the food are converted into a fine pap, dissolved by the digestive
action of the stomach. By a rigorous sorting the pure lime is separated
from the rest, and it is made into a sort of chalk soup which at the
right moment oozes around the egg and hardens into a shell. By
swallowing little particles of lime, the hen, as you see, lays by
materials for her eggshell. If these materials were wanting, if the
food given her did not include lime, if, imprisoned in a cage, she
could not procure carbonate of lime for herself by pecking in the
ground, she would lay eggs without any shell and simply covered with a
flabby skin.”
“Those soft eggs that hens sometimes lay come then from lack of lime?”
asked Louis.
“They either come from the bird’s not having had the necessary
carbonate of lime in her food or in the earth she pecked, or else her
bad state of health did not permit the transformation of the little
stones into that chalky pap which molds itself around the egg and
becomes the shell. In countries where carbonate of lime is scarce in
the soil, or even totally lacking, it is the custom to break up the
eggshells and mix the coarse powder in the fowl’s food. It is a very
judicious way of giving the hen in the most convenient form, the stony
matter necessary for the perfect formation of the egg.”
“Sometimes,” observed Louis, “we find on the dunghill eggs of a queer
shape and as soft as hens’ eggs without the shell. Instead of a
chicken, a snake comes out of them. They say they are laid by young
cocks.”
“You are repeating now one of the false notions prevalent in the
country—a foolish notion springing from a basis of actual fact. It is
perfectly true that eggs soft, rather long, almost cylindrical, and of
the same size at both ends, may be turned up by the fork as it stirs
the warm manure of a dunghill. It is also perfectly true that from
these eggs snakes are hatched, to the great surprise of the innocent
person who thinks he sees there the product of some witchcraft. What is
false is the supposed origin of the egg. Never, never has the cock, be
he young or old, the faculty reserved exclusively for the hen, the
faculty of laying. Those eggs found in dunghills, and remarkable for
their strange shape, do not come from fowl; they are simply the eggs of
a serpent, of an inoffensive snake which, when opportunity offers,
buries its laying in the warm mass of a dunghill to aid the hatching.
It is quite natural, then, that from serpents’ eggs serpents should
hatch.”
“The ridiculous marvel of the supposed cock’s eggs,” returned Louis,
“thus becomes a very simple thing; but one must first know that
serpents lay eggs.”
“Henceforth you will know that not only serpents but all reptiles lay
eggs just as birds do. Snakes’ eggs are flabby, and for covering have
only a sort of skin resembling wet parchment. Moreover, they are long
in shape, which is far from being the usual form. But the eggs of some
reptiles, notably of lizards, have the shell firm and of the fine oval
shape peculiar to birds’ eggs. If you ever encounter in holes in the
wall, or in dry sand well exposed to the sun, little eggs, all white,
with shell as fine as a little canary bird’s, do not cry out at the
strangeness of your discovery; you will simply have come across the
eggs of a gray lizard, the usual inhabitant of old walls.”