The Lumleian lectures on the muscular arterioles : their structure and function in health and in certain morbid states : delivered at the Royal College of Physicians / by George Johnson.

  • Johnson, George, 1818-1896.
Date:
1877
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Licence: Public Domain Mark

Credit: The Lumleian lectures on the muscular arterioles : their structure and function in health and in certain morbid states : delivered at the Royal College of Physicians / by George Johnson. 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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    These phenomena would be explained by extreme contraction of the muscular arterioles, resisting the escape of blood from the arterial trunks into the capillaries. Kussmaul and Tenner endeavoured to support the theory of arterial spasm by experiment, and to some extent they succeeded. In each of two white rabbits, they ligatured the two subclavians and one carotid ; the cervical sympathetic, on the other side, was then exposed and galvan- ised, with a view to excite contraction of the arterioles by the stimulus con- veyed through the vaso-motor nerves. In two animals, no effect was pro- duced ; but in the third, the background of the eye became completely pale; the pupil dilated, so that the iris could scarcely be seen ; the neck was drawn back, and violent convulsions occurred. The elec- trodes being removed, the spasms ceased, the pupil contracted, and the background of the eye became red; but the animal continued in a swooning condition. After some minutes, electricity applied to the sympathetic nerve produced the same effect as at first. A third attempt to excite convulsion did not succeed. The authors suggest that these experiments deserve repetition, with a view of rendering certain what at present is probable, namely, that epileptic convulsions can be brought about by contraction of the blood- vessels induced by the vaso-motor nerves. According to this theory, then, epilepsy is the result of sudden anaemia of the brain; and this ansemia, when not caused by a sudden and profuse haemorrhage, or by some impediment to the circulation outside the cranium, is due to an extreme contraction of the muscular arterioles. This arterial contraction may be determined by two main classes of causes : 1. By a purely nervous reflex influence, such as, for example, may be excited by anger or terror, by the irritation of the gums during dentition, by a calculus in the kidney, the ureter, or the gall duct, or by worms in the intestines. 2. In the second class of cases, a blood-poison is the exciting cause of the arterial spasm and the resulting epileptic convulsion. This in- cludes all cases in which convulsions result from retained excreta, of which uraemic convulsions are a typical example. From the preceding narrative of facts, it appears to be highly pro- bable that uraemic convulsions are directly due to a sudden and extreme anaemia of the brain, resulting from contraction of the cerebral arte- rioles, and that the arterial contraction is excited by the influence of impure blood upon the vaso-motor nerves and centre.