Action of digitalis on the blood-vessels / by T. Lauder Brunton ; in conjunction with Adolph Bernhard Meyer.

  • Brunton, Thomas Lauder, Sir, 1844-1916.
Date:
[1873]
Catalogue details

Licence: Public Domain Mark

Credit: Action of digitalis on the blood-vessels / by T. Lauder Brunton ; in conjunction with Adolph Bernhard Meyer. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    mum height of the wave 44, while in that taken when the action of the digitalin was greatest, the mean pressure is some- what over 90 millimetres, and the maximum 104. The fall of pressure ought, therefore, to be more abrupt, but instead of this it is more gradual. This alteration cannot, we think, be ex- plained by any oscillations of the mercurial column indepen- dently of the blood-pressure, and can only be due to contraction of the arterioles retarding the flow of blood from the arterial into the venous system during the cardiac diastole. In a recent paper,* Boehm considers that the rise in blood-pressure pro- duced by digitalis, is chiefly due to the increased action of the heart, and that the condition of the arterioles has little or nothing to do with it. He seems, however, to interpret tracings of the blood-pressure in the arteries of mammals in the same way as those obtained from the excised heart of the frog, and apparently forgets that while in the latter the form of the diastolic as well as of the systolic curve depends oh the heart alone, in the former the heart can have but little or no influence on the pressure in the arterial system during the diastole, since all communication between them is prevented by the closure of the sigmoid valves. The curves which he gives confirm our views, for they show the same gradual fall in the pulse-wave, after the injection of digitalis, that ours do, and being traced with Fick’s spring-kymographion, are free from any fallacies due to oscillations of the mercurial column. The continued high pressure he observed during prolonged stoppage of the heart, and which he attributes to continuous cardiac systole, we would ascribe to contraction of the vessels so far as it is not due to changes in the respiration. If the arterioles were not' con- tracted the pressure would faU, as, e.g., in the experiments of Ludwig and Hafiz.f We next attempted to ascertain whether the slowing of the pulse is due to a direct specific influence of the drug on the roots of the vagus as supposed by one of us,$ or to the stimula- tion of these roots by the increased pressure of blood in the ♦ Ffliiger's Archiv, vol. v, 190. t Ludwig’s Arbeiten, 1870. t Brunton, Op. cit.