3


When the egg is now ten days old the chick and all its parts are
distinctly visible. The head is still larger than the rest of its
body, and the eyes larger than the head, but still devoid of vision.
The eyes, if removed about this time, are found to be larger than
beans, and black; if the cuticle be peeled off them there is a white
and cold liquid inside, quite glittering in the sunlight, but there is
no hard substance whatsoever. Such is the condition of the head and
eyes. At this time also the larger internal organs are visible, as
also the stomach and the arrangement of the viscera; and veins that
seem to proceed from the heart are now close to the navel. From the
navel there stretch a pair of veins; one towards the membrane that
envelops the yolk (and, by the way, the yolk is now liquid, or more so
than is normal), and the other towards that membrane which envelops
collectively the membrane wherein the chick lies, the membrane of
the yolk, and the intervening liquid. (For, as the chick grows, little
by little one part of the yolk goes upward, and another part downward,
and the white liquid is between them; and the white of the egg is
underneath the lower part of the yolk, as it was at the outset.) On
the tenth day the white is at the extreme outer surface, reduced in
amount, glutinous, firm in substance, and sallow in colour.