Lectures on dermatology : a synopsis of diseases of the skin, delivered in the Royal College of Surgeons of England, January, 1870 / by Erasmus Wilson.

  • William James Erasmus Wilson
Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on dermatology : a synopsis of diseases of the skin, delivered in the Royal College of Surgeons of England, January, 1870 / by Erasmus Wilson. Source: Wellcome Collection.

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

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    tioii of the word rusli, as though it would express a hurrying of blood to the surface; it is, in fact, a blush, not a physiological blush disappearing as suddenly as it has arisen, but a pathological blush, more or less enduring and permanent. Patholo- gically it is a state of distension of the vessels of the skin with blood—in fact, a hypersemia—and hyper- Eemia of the skin may be active or passive. At the present day we look upon hypersemia as being due I to a loss of power of the special nerves of the blood- fvessels, the vaso-motor nerves, and active or passive is the expression of the degree of loss of power which exists ; it may be transient, or tem- porary, or permanent; it may be the consequence of an irritant; or it may be mechanical, as in the case of obstruction of the general circulation. As might be supposed, there will be a difference of appearance of the part corresponding with these opposite causes ; in active hypersemia the current of the blood may be unimpeded, there will be simply a larger quantity of blood in the vessels, and the ]Dart will be bright and arterial in its redness; whereas, in passive hypersemia, and with an impeded and par- tially suspended circulation, the colour will shade by degrees into that of venous blood, and become more or less crimson, or purple, or livid. The erythemata are essentially superficial, as though the peripheral nervous plexuses and peri- pheral capillary plexuses were principally concerned; and associated with this periphericity of character is a tendency to spread over the surface like a wave, to extend by the circumference, while the action in the centre may, at the same time, be subsiding; to disappear suddenly in one place, and reappear as suddenly in another. I may illustrate these remarks by the mention of erythema circinatum, of erythema iris, of erysipelas, and urticaria. And, in all these phenomena, three factors are principally concerned, namely, the cause, the nerves, and the vessels.
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