The Works of William Harvey M.D.: Translated from the Latin with a life of the authorHarvey, William
Science
The Works of William Harvey M.D.: Translated from the Latin with a life of the author
Harvey, William
Blood -- Circulation -- Early works to 1800; Embryology -- Early works to 1800; Physiology -- Early works to 1800
Towards the end of this day and the beginning of the seventh, the toes
are distinguished, and the embryo already presents the outlines of the
chick, and opens its beak, and kicks with its feet; in short, all the
parts are sketched out, but the eyes, above all, are conspicuous. The
viscera, on the contrary, are so indistinct, that Coiter affirms, that
whilst he plainly saw the eyes and beak he could discover no viscus,
even obscurely and confusedly shadowed forth.
The changes that take place from the beginning of the sixth to the end
of the seventh day, occur for the major part in some eggs more quickly,
in others a little more tardily. The coats of the eyes are now visible,
but they only include a colourless and limpid fluid in their interior.
The eyes themselves project somewhat beyond their orbits, and each of
them does not less exceed the brain in size, than the head with which
they are connected exceeds the whole of the rest of the body.
The vesicle, which like a ridge or crest expands beyond the confines of
the brain, occupies the place of the cerebellum; and, like the other
vesicles, is filled with a transparent fluid.
The brain is perceived to be obscurely bipartite, and refracts the light
less than the cerebellum, though it is of a whiter colour. And as the
heart is seen lying without the confines of the thorax, so likewise does
the cerebellum protrude beyond the limits of the head.
If the head be removed, the vessels ascending to the brain may be
observed as bloody points, with the use of a magnifying glass. And now,
too, the rudiments of the spine begin to be first perceived distinct
from the rest of the pulp, of a milky colour, but firmer consistence. So
in the same way, and like flimsy threads of a spider’s web, the ribs and
other bones make their appearance in the guise of milky lines, amidst
the pulp of the body; and the same thing appears more clearly in the
formation of the larger oviparous animals. The heart, lungs, liver, and
by way of intestines certain most delicate filaments, all present
themselves of a white colour. The parenchyma of the liver is developed
upon delicate fibrous stamens over the umbilical vein at the part where
it enters, almost in the same manner as we have said that the rudiments
of the body grow to the vein descending from the heart, or the vesicula
pulsans. For in the same way as grapes grow upon the stalk of the bunch,
buds upon twigs, and the ear upon the straw, does the liver adhere to
the umbilical vein, and arise from it, even as fungi do from trees and
excessive granulations from ulcers, or as sarcoses or morbid growths
spring around the minute branches of conterminous arteries by which they
are nourished, and occasionally attain to an excessive size.
Public-domain text, read in full here on John Shaqi.
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