A lecture on the diagnosis of disease of the heart / by George W. Balfour, M.D.

  • George William Balfour
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: A lecture on the diagnosis of disease of the heart / by George W. Balfour, 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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    murmur and the tactile perceptibility of tlie vibrations are in some degree proportionate to the force exerted in producing this sonorous vein, while its musical character must of course depend upon the rapidity of these vibrations. But the exact manner in which these sonorous veins are pro- duced, and the mode in which the production and conduction of their sonorous vibrations may be modified by evident or imper- ceptible alterations in the heart's action itself, and in the position of the patient himself, are problems which yet remain to be defined, and an accurate experimental investigation of these problems will certainly prove to be of the utmost importance in the accurate diagnosis of cardiac and vascular diseases. of ansemia are due aux vibrations de la veine fluide intravasculaire, vibrations Fia. 5. q^i-i produisent toujours quand le sang penetre fig. 6. ^ avec line force suffisante dans une partie reellement ou comparativement dilatee de Fappareil circula- toire.—P. 933. Felix Savart has described the phenomena pre- sented by a liquid vein of water flowing through a circular oriflce in the bottom of a vessel. The part of the vein a h, Fig. 5, is steady and limpid, presenting the appearance of a solid rod, which obstructs vision and wets the linger when passed through it. This decreases in diameter till it reaches a point (h) of maximum contrac- tion, beyond which it is turbid and unsteady, marked by periodic swellings and contractions, does not wet the finger when passed through it, and does not obstruct vision, even though the fluid be mercury. Ai; 6, in fact, the liquid is no longer continuous, but resolves itself into a series of liquid spherules, which have an appearance of turbid continuity, from their rapid succession never permitting the primary impression wholly to fade from the retina till succeeded by a second. Fig. 6 represents this fluid vein illuminated by an electric flash, when the drops of which it consists are seen as it were motionless in the air, and the cause of the periodic swellings and contractions are at once apparent; for these spheroidal drops, when first detached, have their long axis ver- tical ; when abandoned to their own molecular forces they seek to become spheres, and, like a pendulum in motion seeking to return to rest, the contraction goes too far, and they become flattened spheroids, which again elongate verti- cally ; hence the appearance of alternate swellings and contractions. Savart traced the production of these pulsations to the orifice through which the vein passed, but did not regard them as the result of friction. Under moderate pressure they succeed each other sufficiently rapidly to produce a feeble musical note, the pitch of which may be fixed by allowing the drops to fall upon a stretched membrane.— Vide Tyndall On Sound. London : 1869 : p. 244, etc.
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