An introduction to medical literature, including a system of practical nosology : intended as a guide to students, and an assistant to practitioners. Together with detached essays, on the study of physic, on classification, on chemical affinities, on animal chemistry, on the blood, on the medical effects of climates, on the circulation, and on palpitation / by Thomas Young.

Date:: 1823

Credit: An introduction to medical literature, including a system of practical nosology : intended as a guide to students, and an assistant to practitioners. Together with detached essays, on the study of physic, on classification, on chemical affinities, on animal chemistry, on the blood, on the medical effects of climates, on the circulation, and on palpitation / by Thomas Young. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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albumen. Afh. III. 7.] Since, therefore, the arterial fibres have neither the structure nor the chemical composition of muscles, they cannot either be muscular, or fulfil the office of muscles, which indeed is sufficiently apparent from their elasticity. This elasticity, however, supplies the place of muscular power; and Haller’s description of the pulse is correct, notwithstanding his idea of the cause of the con- traction of the arteries is confuted. On the other hand, Bichat’s opinion, that the arteries are not dilated, but only vibrate about their situation, on account of their numerous flexures, when the heart forces the blood into them, must be incorrect, being contrary to the mathematical laws of hydrostatics. Since it is proved, by chemical analysis, that the fibrous membrane of the arteries is not muscular, and consequently cannot have any power to contract itself, and since it follows necessarily from its elasticity, that it must be dilated when the heart pours out its contents, and after- wards, while the heart is at rest, resume its former dimen- sions, it is evident that the frequency of the pulse can never be different at the same time in different parts of the same individual. Every other inequality, except that of fre- quency, may possibly take place. Many medical writers have related cases in which such inequalities are supposed to have been observed : but the observations must have been erroneous, since the thing is utterly impossible. The deci- sion of this question, which has been so long disputed, is of great importance to the science of medicine ; since it proves that the branches of the arteries can never be thrown into spasmodic action, and that all the disturbances of the cir- culation, which have been attributed to spasms of the larger vessels, must be strictly limited to the obviously muscular parts, that is, the heart and its auricles, and perhaps some- times the muscular fibres which are seen to extend a little way from it, on the trunks of the great veins which enter it. [Whatever reason there may be for admitting a part of these arguments as correct, it does not appear to be by any means demonstrated, that every muscular part must neces- sarily contain fibrin : on the contrary it seems to be proved,

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