On the use of the sphygmograph in the investigation of disease / by Balthazar W. Foster, M.D.

  • Foster, Balthazar Walter, 1840-1913.
Date:
1866
Catalogue details

Licence: Public Domain Mark

Credit: On the use of the sphygmograph in the investigation of disease / by Balthazar W. Foster, M.D. Source: Wellcome Collection.

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

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    a fruitful subject; and, moreover, our means of ap- preciating its finer differences have been very imper- fect. The finger placed on an artery perceives only the grosser peculiarities of the arterial movement, such as force, frequency, and regularity; the more subtle differences, in consequence of the fleeting cha- racter of the sensation experienced, escape our notice, or, when observed, convey no distinct or explicable idea to our minds. In order, therefore, that the pulse should yield valuable evidence in disease, we must first understand thoroughly its nature and causes; and secondly, we must so improve our means of in- vestigating it, that we may recognise, and retain a knowledge of, its finer features. The sensation of hardening and elevation felt by the finger placed over an artery, at each contraction of the heart, has been termed the arterial pulse. At each systole of the ventricle, we know that the blood driven into the arteries produces a varying amount of dilatation of the vessels. The arteries, distended by each new blood-wave, tend, by virtue of their elasticity, to contract upon their contents, and, while modifying by their recoil the ventricular force, they nevertheless drive the blood on its course. The greater the distension of the vessels, the stronger will be this elastic recoil, or, in other words, the arterial tension. The phenomena of the pulse are thus intimately connected with the tension of the arteries, and may be said to be a direct result of the changes which the arterial tension experiences under cardiac action. Whenever we place the finger on an artery situated in a position favourable to compression (e. g., over an osseous plane), the alterna-