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
I am myself farther satisfied from numerous experiments, that not only
is motion inherent in the punctum saliens, which indeed no one denies,
but sensation also. For on any the slightest touch, you may see the
point variously commoved, and, as it were, irritated; just as sensitive
bodies generally give indications of their proper sensations by their
motions; and, the injury being repeated, the punctum becomes excited and
disturbed in the rhythm and order of its pulsations. Thus do we conclude
that in the sensitive-plant, and in zoophytes, there is inherent
sensibility, because when touched they contract, as if they felt
uncomfortable.
I have seen, I repeat, very frequently, and those who have been with me
have seen this punctum, when touched with a needle, a probe, or a
finger, and even when exposed to a higher temperature, or a severer
cold, or subjected to any other molesting circumstance or thing, give
various indications of sensibility, in the variety, force, and frequency
of its pulsations. It is not to be questioned, therefore, that this
punctum lives, moves, and feels like an animal.
An egg, moreover, too long exposed to the colder air, the punctum
saliens beats more slowly and languidly; but the finger, or some other
warmth being applied, it forthwith recovers its powers. And farther,
after the punctum has gradually languished, and, replete with blood, has
even ceased from all kind of motion, or other indication of life, still,
on applying my warm finger, in no longer a time than is measured by
twenty beats of my pulse, lo! the little heart is revivified, erects
itself anew, and, returning from Hades as it were, is restored to its
former pulsations. The same thing happens through heat applied in any
other way--that of the fire, or of hot water--as has been proved by
myself and others again and again; so that it seemed as if it lay in our
power to deliver the poor heart over to death, or to recall it to life
at our will and pleasure.
What has now been stated, for the most part comes to pass on the fourth
day from the commencement of the incubation--I say, for the most
part,--because it is not invariably so, inasmuch as there is great
diversity in the maturity of eggs, and some are more speedily perfected
than others. As in trees laden with fruit, some, more forward and
precocious, falls from the branches, and some, more crude and immature,
still hangs firmly on the bough; so are some eggs less forward on the
fifth day than others in the course of the third. This, that I might
give it forth as a thing attested and certain, I have repeatedly
ascertained in numerous eggs, incubated for the same length of time, and
opened on the same day. Nor can I ascribe it to any difference of sex,
or inclemency of weather, or neglect of incubation, or to any other
cause but an inherent weakness of the egg itself, or some deficiency of
the native heat.
Public-domain text, read in full here on John Shaqi.
The Works of William Harvey M.D.: Translated from the Latin with a life of the author — John Shaqi
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