On the sounds caused by the circulation of the blood : being a thesis read in the University of Dublin for the degree of M.D., at the winter commencement, 1860 / by Arthur Leared.

  • Leared, Arthur, 1822-1879.
Date:
1861
Catalogue details

Licence: Public Domain Mark

Credit: On the sounds caused by the circulation of the blood : being a thesis read in the University of Dublin for the degree of M.D., at the winter commencement, 1860 / by Arthur Leared. 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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    SOUNDS CAUSED BY THE CIECULATION OF THE BLOOD. It is a matter not merely of interest, but of great importance, to determine the causes of the sounds produced by the circula- tion of the blood. But while the labour bestowed on it has been proportionably great, the want of general principles is amply proved by the very contradictory results. Even in the explanation of the different sounds by the same authorities there is much discrepancy. Thus we find the cause of the first sound of the heart affirmed to be totally different from that of the second sound, which is prima facie improbable. The explanation I am about to give is consonant with general laws, and is certainly more comprehensive than any other that has been proposed.* Two essential circumstances relative to the formation of sound have been overlooked by all investigators—the effect of pressure on the blood in the heart and vessels, and the effect of the consistency of the blood. All sounds formed in connexion with the circulation are produced by and in the blood itself, and their mechanism is virtually the same.f If this statement be true, it would be found in practice, that a sound of one species would be liable to * Some of my views on this subject were published in the Dublin Journal of Medical Science for May, 1852. f Some authors contend that the heart's sounds are due to a number of coincident causes. I agi-ee with Dr. Billing, ( Diseases of the Lungs and Heart, p. 27,) that in this case the axiom of Newton should be kept in view, that more causes than are true or sufficient ought not to be assigned. But whether minor causes exist or not I do not stop to inquu-e, as my explana- tion refers to the cause mainly concerned. a2