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
And now the arteries are seen distinctly accompanying the veins, both
those that proceed to the albumen and those that are distributed to the
vitellus. The vitellus also at this time liquefies still more and
becomes more diffluent, not entirely, indeed, but, as already said, that
portion of it which is uppermost; neither do the branches of the veins
proceed to every part of the vitellus alike, but only to that part which
we have spoken of as resembling melted wax. The veins that are
distributed to the albumen have, in like manner, arteries accompanying
them. The larger portion of the albumen now dissolves into a clear
fluid, the colliquament, which surrounds the embryo that swims in its
middle, and comes between the two portions of the vitellus, viz., the
superior and the inferior; underneath all (in the sharp end of the egg),
the thicker and more viscid portion of the albumen is contained. The
superior portion of the yelk already appears more liquid and diffluent
than the inferior; and wherever the branches of the veins extend, there
the matter seems suddenly to swell and become more diffluent.
“On the tenth day,” continues our author, “the albumen subsides, having
now become a small tenacious, viscid, and yellowish mass”--so much of
it, that is to say, as has not passed into the state of colliquament.
For already the larger portion of the white has become dissolved, and
has even passed into the body of the embryo, viz., the whole of the
thinner albumen, and the greater portion of the thicker. The yelk, on
the contrary, rather looks larger than it did in the beginning. Whence
it clearly appears that the yelk has not as yet served for the nutrition
of the embryo, but is reserved to perform this office by and by. In so
far as we can conjecture from the course and distribution of the veins,
the embryo from the commencement is nourished by the colliquament; upon
this blood-vessels are first distributed, and then they spread over the
membrane of the thinner albumen, next over the thicker albumen, and
finally over the vitellus. The thicker albumen serves for nutriment
after the thinner; the vitellus is drawn upon last of all.
The delicate embryo, consequently, whilst it is yet in the vermicular
state, is nourished with the thinnest and best concocted aliment, the
colliquament and thinner albumen; but when it is older it has food
supplied to it more in harmony with its age and strength.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account