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

  • Jamieson, W. Allan (William Allan), 1839-1916.
Date:
1889
Catalogue details

Licence: Public Domain Mark

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

    26/654 (page 4)
    least, into four layers. Of these two belong to the horny, and two to the mucous or vegetative layer. The most external layer is essentially insensitive and protective. It consists of flattened cells which have become converted into keratine, and are, except on the very surface, intimately and closely united, and with difficulty separable. The most external of these cells are being gradually loosened, and are continually cast off. This shedding is nearly imperceptible in health, as indeed all the waste of the body is. It is this which makes up the greater part of the cloud of dust which flies off when a stocking is shaken after having been worn for a few days. When this dust is examined, it is found to consist of dry plates of keratine, which contain no or the mere trace of a nucleus, and are granular or fatty. Beneath the true horny layer lies the band of Schron or Oehl's stratum lucidum, a thin, brightly refracting, and in- distinctly striated layer, which stains red with picro-carmine. Unna thinks that when the skin becomes suddenly heated, the narrow slit-like opening in this, through which the duct of the sweat gland passes, becomes suddenly occluded, no sweat can pass, and the surface remains dry. The same result, dryness of the surface, may be caused by swelling of the epidermis from prolonged soaking in water, or from the infiltration of chronic eczema. Below this, again, is the stratum granulosum, or layer of Langerhans, which contains the peculiar substance called eleidin, to which attention has of late been directed. Unna has named this kerato-hyaline. It consists of oil-like granules contained in the cells of the deeper epidermic layers, and in those of the mucous membranes. Unna regards it as connected with keratinization, while Eanvier is of opinion that the cornification of the hair shaft and that of the nails is completed without any participation on the part of the eleidin, while it has nothiDg to do with the lubrication of the horny cells.1 • 1 Monatslufte fur praktischc Dcvmatologic, No. 13, 1S83.