On the law which regulates the frequency of the pulse / by A. H. Garrod, B.A.

  • Garrod, Alfred Henry.
Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: On the law which regulates the frequency of the pulse / by A. H. Garrod, B.A. 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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    and shortens it, in other words strengthens the heart, according to the law that may be stated thus, the nutrition of the heart varies as the square root of the time during which the coronary circulation is maintained. It will strike some as peculiar that no mention has yet been made of the influence of the nervous system on the heart. But it appears to me that the facts which have been brought forward have not called for any special reference to it. May not the law it has been my endeavour to prove, be but an expression of that action in the healthy body ? For it must depend on a somewhat complicated mechanism, as is shewn by the fact that it is almost impossible to contrive a self-acting engine which would pulsate in accordance with its re- quirements. As is well known, the effect on the kymogra- phion trace, of stimulating the depressor nerve, is greatly to amplify the oscillations, and at the same time to lower the mean pressure ; while»cutting the pneumogastrics produces the reverse effects. The larger oscillations of the hasmadynamometer column in the former case, shew that the proportionate tension-fall and the time of pulsation are both greatly increased, and from previous considerations it is evident that these are necessarily associated, when as now, no influence is being exerted on the peripheral vessels.* In rabbits the normal fall of tension as judged by the hsemadynamometer trace is about ^th of the whole, while when the depressor is stimulated it may increase to ^th or more.