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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    any given puLse rate do not vary in their ratio to one another; but the length of the first part varies inversely as the square root of the rapidity of the pulse. A second series of measurements of the cardio- arterial intervals, published in the Proceedings of the Royal Society, have further verified the law just stated, and in the rest of this paper it will be assumed as proved. No theory respecting the cir- culation throws light on its significance; but the one which it has been my endeavour to demonstrate above gives a very satisfactory explanation of it, which will now be considered in detail. First, the heart's beat consists of two parts, which for any given pulse rate do not vary in their ratio to one another. It having been proved pre- viously that the pulse rate does not depend on the blood pressure, and, as shown now, the length of the first part of the heart's beat not varying when the pulse length is constant, it is evident that the length of the first part of the pulse beat does not depend on the blood pressure in any way. Again, the first part of the pulse beat is com- pound, for it is the interval between the commence- ment of the cardiac or ventricular systole and the closure of the semilunar valves; therefore it may be divided into the systole and the valve-closure interval. Physiologists have laid very little stress on this valve-closure interval, it generally being considered as instantaneous. But in the study of cardiograph tracings it is to be remembered that the distances between events occurring within one-fiftieth of a c 2