(seq. 57)

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25 Lect. 2

He opened the Carotid Artery of a Mare, & fixed a
Glass Tube into it; & after the Blood had rose therein to the
Height of some [Feet?], its Weight overcame the Force of the Heart,
so that the Animal could not bleed to Death. And the Blood
alternately rose & fell again in the Glass Tube, & those two Mo-
tions in the Tube represented the two Motions of the Heart
& Arteries. When the Heart ontracted & propelled the Blood with
a Terk, the Blood rose in the Tube, but on the Intermission
thereof, or in the Systole of the Arteries it fell much - The
Pulse from the Touch is generally imagined to swell more, than
it really does, which is so little, as to be scarce perceptible by
the Eye, but the Stroke is larger in Proportion to the size of the Artery, & may be rendred visible by Art vide p 29 [?] This Swell is not in
all Parts of the Artery at the same Time; tho' an Explanation of
this Proportion is attempted, by supposing, that the Arteries being
full of Blood, at each Stroke the Blood is thrust forward thro' the whole
Canal, & at both Ends at the same Time by the subsequent Blood,
which is thrown out from the Heart, & which at the same Time
propells all the Blood, which is before it. If the Arteries were rigid
Pipes of Brass or Silver, this might be a proper Method of Reas-
oning, but as the Coats are elastic, we may judge a priori, that
the Motion is successive, which is perceptible indeed by feeling
the Carotid Artery, & that in the Inside of the Anele tohether

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