A treatise on the blood, inflammation, and gun-shot wounds / by John Hunter ; with notes by James F. Palmer.

  • John Hunter
Date:
1840
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on the blood, inflammation, and gun-shot wounds / by John Hunter ; with notes by James F. Palmer. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    ceived them to be perfectly sound, yet if there could have been any diminution of the elasticity from use, it would be most considerable in the aorta. These experiments were made on different arteries with nearly the same result, and seemed to prove that there was almost the same extent of elasticity, though not the same powers. An artery being composed of an elastic and inelastic substance, its elasticity is not altogether similar to that of a body which is wholly elastic. There is an effect produced from stretching it that is expressive of the nature of both these substances, till it gives way or breaks ; for an artery has a cheek to its yielding to so great a degree, and is stopt at once, when stretched to a certain point,* which cheek is occasioned probably by the muscular, together with the internal inelastic coat.f To prove the muscularity of an artery, it is only necessary to compare its action with that of elastic substances. Action in an elastic body can only be produced by a mechanical power; but mus- cles acting upon another principle can act quickly or slowly, much or little, according to the stimulus applied; though all muscles do not act alike in this respect. If an artery is cut through, or laid bare, it will be found that it contracts by degrees till the whole cavity is closed; but if it be allowed to remain in this contracted state till after the death of the animal, and be then dilated beyond the state of rest of elastic substances, it will only contract to the degree of that state; this it will do immediately, but the contraction will not be equal to that of which it was capable while alive. The posterior tibial artery of a dog being laid bare, and its size attended to, it was observed to be so much contracted in a short time as almost to prevent the blood from passing through it, and when divided the blood only oozed out from the orifice. On laying bare the carotid and crural arteries, and observing what took place in them while the animal was allowed to bleed to death, these arteries very evidently became smaller and smaller. When the various uses of arteries are considered, such as their forming different parts of the body out of the blood, their perform- ing the different secretions, their allowing at one time the blood to pass readily into the smaller branches, as in blushing, and at another preventing it altogether, as in paleness from fear : and if to these we add the power of producing a diseased increase of any or every part of the body, we cannot but conclude that they are possessed of muscular powers. . The influence of the heart in the body, like that of the sun in the planetary system, we know extends to every part; all the parts of * This gives a determined size to an artery. f [Thus Poiseuille, by direct experiment proved that the force of reaction ex- cited by the distention of a recent artery was greater than the force used to distend it, and greater also than an artery could exert some time after death, before de- composition had commenced. This is only to be accounted for by its muscu- larity. (Journ. de Phys.par M. Magendie, viii. 272.)]