Selected monographs on dermatology / P.G. Unna [and others].

Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs on dermatology / P.G. Unna [and others]. Source: Wellcome Collection.

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    same category belongs the anasmia which accompanies or precedes nausea (ab injectio medicamentis, chloroform, swing- ing, and sea-sickness), and in which there is often an accom- panying inhibition of the splanchnics, causing plethora of the intestinal tract, the anaemia of the skin being here regulative. Reflex spasm of the cutaneous arteries is also often caused by the prodromata of an epileptic fit, by psychical disturbances (fear, sudden terror), and by strong stimulation of sensory nerves, especially of the abdomen, as in colic. The goose- skin due to mental perturbation indicates, moreover, powerful stimulation of all the unstriped cutaneous muscular tissue, including the vascular. A secondary adaptive contraction of the dermal vessels gives rise to the pallor following night-watching and exces- sive muscular or cerebral activity, when there is a collateral overfilling of the vessels of internal organs, according to their needs. The most important example of a general contraction of the cutaneous vessels is seen in the signs of all acute infec- tive diseases. Here the poison circulating in the blood supplying the vaso-motor centres, gives the stimulus which results in the periodic contraction of the peripheral vessels. If the rigor be severe the vessels of the superficial muscles are also affected, and those of the internal organs become abnormally full. Hence the temperature of the surface falls, and that of the deeper parts of the body rises. Influences which paralyse the vessels, such as warmth, can partly over- come their tonic contraction. As is well known, during the rigor the temperature of the closed axilla is already rising. On the other hand, cold accelerates the rigor, showing that the tone of the vessels, in the interval between the rigors, is really raised, and only kept in check by the greater warmth of the blood and the increased cardiac action. Certain organic poisons, especially strichnine and ergotine, increase the tonic contraction of the peripheral vessels, although there is not the arterial spasm of rigor; and the pallor after acute poisoning with alcohol is similarly pro- duced, by the products of its decomposition. It thus appears that it is not a slight irritation which causes, reflexly or directly, a general cutaneous anaemia, but