Elements of human physiology / by L. Hermann ; translated from the sixth edition by Arthur Gamgee.

  • Gamgee Arthur, 1841-1909.
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: Elements of human physiology / by L. Hermann ; translated from the sixth edition by Arthur Gamgee. 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.

    109/620 (page 89)
    The contents of the left ventricle, that is, the quantity of blood pumped out during one systole, has been calculated variously at from 150 to 100 grammes. The folloAving are the principal methods: 1. (Legallois, Oolin.) The contents of the ventricle may be directly measured by tilling the ventricle, before rigor mortis sets in, with a fluid of Imown specific gravity, and weighing before and after: in this case, as it is impossible to imitate the normal pressure of the heart, the residt is valueless. 2. (Volkmann.^) The diameter of the aorta, and the speed of the current of blood within it, are used to calcidate how high a column of blood the heart expels during a unit of time; knowing the frequency of the pulse, the quantity emptied during each systole is found to be about ^--^ of the weight of the body ; that is, in a body weighing 75 kgi-ms. = 187'5 grms. 3. (Vierordt.^) Given the speed of the blood in any section of the arterial sj'stem, the area of that section, and also the area of the aorta, the mean speed in the latter can be calculated, and also the quantity of blood discharged fi-om the left ventricle duruig a imit of time, since the speed in any two sections is in inverse relation to their contents. The quantity of blood wlaich the right ven- tricle drives into the pulmonary arterial system must be verj' nearly the same as that expelled by the left, because the same quantity of blood flows through every section of the vascular system during the same time (see below), and both sides of the heart contract synchronoiisly. The distension of the arteries and the slackness of the veins show in the simplest manner how much higher is the tension (blood pressure) in the arterial than in the venous system ; this is also shown by the height of the jet of blood issuing from an open vessel; from a vein this is seldom of a notable height, whilst the blood from an artery, on the other hand, spurts to the height of several feet. Absolute determinations of the pressure of the blood may be made by connecting the vessel laterally with a manometer: or the blood itself may be employed as the manometric fluid, by letting it rise in a vertical tube, and measuring the height of the column (Hales It is much more advantageous, however, to use the mercurial manometer (Poiseuille'') as an ' hsematodynamometer,' placing a solution of sodium bicarbonate between the blood and the mercury to prevent coagulation. A priori, it follows that the blood pressure (that is, the mean pressure, apart from the fluctua- tions of the pulse wave) at one and the same spot of the arterial system will increase: 1. With the fulness of the vascular system, that is, with the quantity of blood. 2. With the frequency and force of the contractions of the heart, for the greater the quantity of blood pumped by the heart from the veins into the arteries, the greater—as is shown above— 2 Volkmann, 7)/e Hmmodynamih nach Versuchen, p. 206, Leipzig, 1850. iA« il' -^'f„.-f'«c/'emun<7e« und Gesetze der Stromgeschwindgkeiten des Bbiles, p. lOd, I'rankfort, 18o8. ' 3 StfUical Essmjs, containing Hcemaataiics, or an Account of sovie HydravUc and Hi/dros- HnTp ^TTu^i T'^ M'' ^''^ '^ Bloodvessels of Animals, §-c. By Stephcu Hale., D.U. I..K 8., KcctorofFnrnngdon. 2nd edition, London, 1740. . 1 oiseuUle, J. L. 31., ' Keclierches sur la force du ccjeur aortique. Paris, 1820.