The elements of physiology : containing an explanation of the functions of the human body : in which the modern improvements in chemistry, Galvanism, and other sciences, are applied to explain the actions of the animal economy / translated from the French of A. Richerand ... by Robert Kerrison.

  • Richerand, A. (Anthelme), 1779-1840.
Date:
1808
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Licence: Public Domain Mark

Credit: The elements of physiology : containing an explanation of the functions of the human body : in which the modern improvements in chemistry, Galvanism, and other sciences, are applied to explain the actions of the animal economy / translated from the French of A. Richerand ... by Robert Kerrison. 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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    XXIII. As the arteries are always full during life, and the blood flows \\ ith so much the less rapidity as they are at a greater distance from the heart, that portion of this fluid vhichthe contraction of the left ventricle propels into the aorta, coming into contact with the antecedent columns, communicates to them the impulse received; but being re- tarded in a direct passage by the resistance opposed, it acts against the parietes of vessels, and extends them on their axis. This lateral action by which the arteries are dilated, depends therefore on their cavities being always filled with a fluid which resists that projected by the heart. This dila- tation, more considerable in larger arteries than in those of smaller diameter, is evident bv a beating known by the name of the pulse; the experiments of Lamure, &c. give us reason to believe that a second cause of this phenomenon is a small change of situation which arteries suffer at the time of dilatation. These changes of situation are particu- larly observable at their curvatures, and where they adhere by loose cellular structure not closely connected to the sur- rounding parts. The pulse is more frequent in children, women, persons of short stature, of strong passions of the mind, and those who undergo violent bodily exercise, than in an adult man of tall stature, serene mind, and quietude. In the first years of life it beats as much as 140 strokes in a minute, but as we advance in age the circulatory motion is retarded, and towards the end of the second year the pulse is only 100 in the same space of time. At puberty 80 pulsations in a minute are usual, about virility only 75, and in elderly per- sons who have attained their sixtieth year, the pulse is re- duced to 60. The inhabitants of cold countries have a slower pulse than those of warm climates, &c. From the time of Galen, the pulse has offered to phy- sicians one of the principal means of distinguishing diseases.