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
That portion of Coiter’s sentence, however, where he says: “the punctus
saliens is now seen in the albumen rather than in the yelk,” is
perfectly accurate. And, indeed, moved by these words, I have inquired
whether the white point in question is turned into the blood-red point,
inasmuch as both are nearly of the same size, and both make their
appearance in the same situation. And I have, indeed, occasionally found
an extremely delicate bright purple circle ending near the ruddy horizon
surrounding the resolved liquid, in the centre of which there was the
white point, but not the red and pulsating point apparent; for I have
never observed these two points at one and the same time. It were
certainly of great moment to determine: Whether or not the blood was
extant before the pulse? and whether the pulsating point arose from the
veins, or the veins from the pulsating point?
So far as my observations enable me to conclude, the blood has seemed to
go before the pulse. This conclusion is supported by the following
instance: on Wednesday evening I set three hen’s eggs, and on Saturday
evening, somewhat before the same hour, I found these eggs cold, as if
forsaken by the hen: having opened one of them, notwithstanding, I found
the rudiments of an embryo, viz., a red and sanguinolent line in the
circumference; and in the centre, instead of a pulsating point, a white
and bloodless point. By this indication I saw that the hen had left her
nest no long time before; wherefore, catching her, and shutting her up
in a box, I kept her upon the two remaining eggs, and several others,
through the ensuing night. Next morning, very early, both of the eggs
with which the experiment was begun, had revived, and in the centre
there was the pulsating point, much smaller than the white point, from
which, like a spark darting from a cloud, it made its appearance in the
diastole; it seemed to me, therefore, that the red point emanated from
the white point; that the punctum saliens was in some way engendered in
that white point; that the punctum saliens, the blood being already
extant, was either originally there produced, or there began to move. I
have, indeed, repeatedly seen the punctum saliens when all but dead,
and no longer giving any signs of motion, recover its pulsatile
movements under the influence of renewed warmth. In the order of
generation, then, I conceive that the punctum and the blood first exist,
and that pulsation only occurs subsequently.
Public-domain text, read in full here on John Shaqi.
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