Selected monographs.

Date:: 1888

Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs. Source: Wellcome Collection.

60/440 (page 44)

4irteries could be easily raised by placing a ligature on periplieral arteries. Observations witli the kymograpb have, however, taught us that that idea is erroneous, and have shown that the organism sets in action compensatoiy arrange- ments whereby, even when large vascular districts are cut off from the circulation, the general blood-pressure is kept at the normal height. The pressure in the aorta can be greatly increased only by ligature of the carotids or, indeed, of one carotid, but, as JSTawalichin (47) has shown, this is merely in consequence of the irritation thereby induced in the vaso-motor centre and of the general vascular spasm which ensues, just as takes place in the first series of •experiments which we have already discussed. Without tying the carotids the pressure in the aorta can be certainly ^nd considerably increased only by applying a ligature to the vessel itself below the diaphragm, butabo-ve the kidneys. Eut the obvious consequence of this is that the supply of blood to the kidneys is almost, although not altogether, cut off, and the experiment is therefore useless for our purposes. Ligature of the aorta alone, below the kidneys, causes no increase of pressure ; Litten, indeed, found a slight increase ■on tying the coeliac and superior mesenteric arteries in addi- tion to the aorta, but this gradually subsided. These facts will cause us to regard the changes which the urine may present after ligature of the aorta below the renal arteries, not as the consequences of the increased arterial pressure, but as ■due rather to the incidental injuries, unavoidable in so serious an operation, to the pressure to which the kidneys ■or their vessels have been subjected, and to laceration and injury of the splanchnic nerves, &c. Considerations of a similar character may be raised against those experiments, by which the blood-pressure can be really raised by placing .a ligature on the aorta and other arteries. And a review of the results obtained by various investigators will confirm ■our scruples. Gr. H. Meyer, who was the first to tie the aorta in order to decide this question, found albumen in the urine passed afterwards, Robinson, on the contrary, found no albumen, Frerichs found traces of it in a few cases, but .invariably considerable quantities when he removed a kidney in addition to tyiag the aorta. The same result was obtained