The aid which experimentation on animals has given to the science and practice of medicine / by Sir Lauder Brunton.

  • Brunton, Thomas Lauder, Sir, 1844-1916.
Date:
[between 1900 and 1909?]
Catalogue details

Licence: In copyright

Credit: The aid which experimentation on animals has given to the science and practice of medicine / by Sir Lauder Brunton. 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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    the pulse has undergone in tracing 1, May 28th, during the short time occupied in re-inking the pen. It would seem from tracings 3 and 4 of the plate that the tension in the right radial was raised more than in the left, and farther experiments with simultaneous tracings are necessary to decide whether the spasm extends to all systemic vessels or to all alike. At the same time that the tension increases the pulse becomes somewhat quicker, which shows that there is some disturbance of the regulating apparatus of the heart, as normally the increased tension acting on the roots of the vagus should slow the pulse. It has been suggested to me (by Professor Ludwig) that the pain in the heart may be due to irritation of its sensory nerves by the great pressure of the blood, and that in the right arm and neck may be due to the same cause acting on the arteries, those of the right side being possibly contracted more than the left. Whenever the tension was lowered by nitrite of amyl the pain dis- appeared from the greater part of the cardiac region, the neck, and the arm, but sometimes remained persistent at a point about twro inches to the inside of the right nipple. This I think indicates that the tension in the right ventricle wras not yet relieved, and the small volume of the pulse (see tracing 3, May 17th) seems to show that the amount of blood passing through the small pulmonary vessels at each systole was small, probably from contraction of their lumen. So long as this condition remained the pain was almost certain to return. It is possible that the right ventricle might not be able to empty itself completely at each systole, was therefore quickly refilled, and consequently contracted frequently, forcing the left ventricle to contract with it, and producing the rapid pulse with small volume seen in tracing 3 of May 17th. The influence of the small vessels of the lungs over the circulation, though in all probability of extreme importance, is a subject of which we know as yet almost nothing. The question whether the contractile power of either ventricle is lessened during the attack is one which cannot be decided with certainty from the present tracings. Digi- talis, which has been recommended on the supposition that the heart is weak during the attack, proved productive in this case of more harm than good, contracting as it does the • small vessels. We may, I think, conclude that the attack in the present