Volume 2

The anatomy of the human body.

  • Bell, John, 1763-1820.
Date:
1797
Catalogue details

Licence: Public Domain Mark

Credit: The anatomy of the human body. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    ter, they can alfo live at leaft as long after you have cut off their heads, or cut out their hearts. Of thofe cold-blooded creatures always either the heart or the arteries are peculiar; the heart is fo in many amphibiae, as in the Turtle, where the heart feems to confifl of three ventricles, but with parti- tions fo imperfect betwixt them that they are ab- folutely as one : this one ventricle gives out both the great arteries; the blood of the lungs and the blood of the body are both mixed in the heart; and fince there are.two arteries conveying this mixed blood, if the two arteries be nearly equal in lize, then it isjuft one half of the blood thrown out by the heart at each ftroke that receives the benefit of the lungs. In many others, as the Frog, the Newt, the Toad, the peculiarity is in the arteries alone; they have oneiin- gle and beautiful heart; there is one large auricle as a refervoir for all the blood both of the body and of the lungs ; there is one neat, fmall, and very powerful ventricle placed below the refervoir, having (Irength quite fufficient for moving both the blood of the lungs and the blood of the body ; and this ventricle gives off an aorta, which foon divides into two branches, one for the body and one for the lungs; and thefe of courfe have but half the blood of this heart expofed to the air: thefe alio are cold-blooded animals. But all breathing creatures, fuch as are called animals of hot blood, have two hearts : the one heart is fending blood through the lungs while the other heart is puftiing its blood over the body ; not the half only ; but the whole blood which is fent by each ftroke pf the heart over the body muft have firft patted through the