The skin in health and disease.

Date:
[1888?]
Catalogue details

Licence: Public Domain Mark

Credit: The skin in health and disease. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    this to accumulate, the openings of the sebaceous, as well as those of the sweat, glands are clogged, work is thrown on other organs of the body, and slow disease is engendered. In this connection may be mentioned an element in the anatomy of the skin which was omitted, in the previous general consideration of the subject, for reasons which will presently appear, namely, the muscles of the skin. In certain animals a very abundant muscular layer is developed immediately beneath the skin, so that they possess the power of wrinkling it and shaking it, in order to rid them- selves of dust, insects, etc. In man this is found only in a few situations and moderately developed; but the human skin possesses within its structure a cer- tain amount of muscular fibres, which are of especial importance in the present study of the sebaceous glands. These muscles in the skin belong to the class of what is called smooth, or unstriped, muscles, which differ from those composing the mass of mus- cles of the limbs, etc., in that they are not con- trolled by the will; they are, therefore, called in- voluntary muscular fibres. These are, of course, extremely small, but are quite readily seen by the microscope. They extend from near the end, _ or deeper portion, of each hair-follicle, in a slanting direction, and terminate, or are inserted, near the outer surface of the corium or true skin. The name given to these muscles is arrectorpili, or, in the plural, arrcctorespilorum, so called because, when they con- tract, they cause the hair to stand more or less erect and to protrude a little from the skin; thus, in the cat, when excited or enraged, all the hairs become