Diseases of the skin : a manual for practitioners and students / by W. Allan Jamieson.

  • William Allan Jamieson
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Diseases of the skin : a manual for practitioners and students / by W. Allan Jamieson. Source: Wellcome Collection.

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    three important networks. One of these surrounds the glands of the skin, and ministers to their nutrition; another is arranged in a horizontal manner in the subcutaneous tissue ; and a third, also horizontal and very fine, lies at the bases of the papilla?, and sends loops into these. So complete is the blood supply, and so sensitive is the skin, that a fine needle cannot be passed into it without causing pain or drawing blood. The two hori- zontal layers of plexuses have not very many intercommunicating branches, hence, as many diseases of the skin spread along the vessels, those which commence on the very surface—as some forms of erythema or superficial eczema—do not for a time implicate the entire thickness of the skin. Another point in the arrangement of the vessels is also peculiar. Each twig as it ascends branches on all sides, and at the periphery of its distri- bution the capillaries of each area inosculate. At the point of union of such areas the skin is less vascular, and this has an influence on the configuration of some eruptions, as some forms of lupus. Lymphatic plexuses also exist abundantly in the skin, and communicate with the interfascicular spaces by true stomata. Under various circumstances lymph accumulates in the skin, but the relations of the lymphatics have not been precisely made out. The nerves of the skin are both of the medullated and non- medullated variety. They convey the sensation of contact with external objects to the sensorium, of pain, indicating the necessity of protection, and they control its nutrition. Though mainly found in the corium, the finer filaments have been traced as far as the second or third row of cells of the rete. They are also supplied to the hair follicles and sebaceous glands. Some end in the tactile corpuscles. The vaso-motor nerves exert an ex- ceedingly important influence over skin diseases, since we see congestion so readily induced, of which the physiological act of blushing is a familiar instance. Paresis, or loss of tone in the vessels of the skin, is a constant feature in certain skin diseases, as acne rosacea.
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