Selected monographs on dermatology / Unna, Nielsen, Duhring, Bronson, Blanc, Berger, Prince-Morrow.

  • New Sydenham Society.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs on dermatology / Unna, Nielsen, Duhring, Bronson, Blanc, Berger, Prince-Morrow. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    lytic phenomena ; and we see how inappropriate, and even misleading, is the expression active hyperaemia, which, is so often used. The hyperemias of stagnation might be much, more appropriately termed active, for here the tone of the vessels comes much more into consideration than their name indicates. It would, indeed, be better to avoid altogether the misleading terms active and passive. If we do not wish to speak of paralytic hyperemias, we might very well employ the words relaxing or fluction- ary, which also contrast well with the expression hyper- emia of obstruction. Clinically, then, two classes of hyperemias are known by the bright red colour of the former, and the bluish-red (cyanotic) tint of the latter; anatomically they are distinguished by the accelerated blood-stream in the former and the retarded in the latter. The terms hyper- emia of relaxation and hyperemia of obstruction hence cover the most important external characters. III. Relaxive Hyperemia.1 Cohnheim has taught us that the best cure for all injuries to the vessels is an increased flow of blood through them. An increased supply of blood to the vessels is only possible by a removal of the normal obstructions to the circulation; and this, especially for the arteries of the skin, means a diminution of their tone. The capillary area of the skin, especially the papillae, is immediately exposed to the full force of the blood-pressure, which is usually broken in the arteries. The skin becomes red, gets hotter, and gives off more heat. While no pathologist would look upon the pus- tules of smallpox as the result of a toxic angioneurosis, such a view of the nature of a prodromal exanthem is, at least, plausible. The former condition is a type of an in- fective embolism of the skin ; the latter is the result of the action of the poison on the central vaso-motor system. 1 Wallungshyperamie, ' Monatsh. f. prakt. Derm.,' Bd. ix, 1889, No. 6. [I have been unable to find an accurate and altogether satisfactory transla- tion for this expression, which literally means a welling up.—Ed.]