Buckmaster's Elements of animal physiology / by John Angell.

  • Angell, John
Date:
1866
Catalogue details

Licence: Public Domain Mark

Credit: Buckmaster's Elements of animal physiology / by John Angell. Source: Wellcome Collection.

    265/384 (page 253)
    Rete Mucosum.—The colour of the skin of the negro and other races lies in the Icrwer and newly formed layers of cells in the cuticle. These layers contain a number of pigment cells, which impart to the skin its distinctive colour. They were fomrerly imagined to constitute a distinct layer, which was termed the rete mucosum. The Cutis, Dermis, Cerium, or True Skin, lies immediately under the cuticle.^ the latter being everywhere moulded to it. It consists—i, of a com- pact layer of areolar tissue; 2, of a network of capil- laries; 3, of a network of nervous fibrils; 4, of a network of lymphatics or absorbents \ 5, of adipose (fat) tissue ; 6, it is supposed to contain muscular fibre; 7, it contains millions of sudoriparous (sweat) glands ; 8, it also contains sebaceous (oil) glands. The cutis is attached to the parts below by areolar tissue. The dense areolar framework which constitutes the greater portion of the true skin consists of a network of white and yellow fibre. The former is most abundant where the skin is compara- tively fixed, but where much motion or extemion is required the latter predominates. The elasticity of the skin depends upon the presence of the yellow elastic fibrous tissue. If the true skin is well macerated in acetic acid the white fibrous element dissolves out, leaving the yellow fibre in diamond-shaped meshes. Areolar tissue is composed principally of gelatin ; the true skin is there- fore readily converted into leather by the process of tanning. At King’s College Museum is exhibited a curious specimen which consists of a piece of good leather tanned from the skin of Bishop, the notorious murderer, who was executed many years ago at the time when '■‘•burking was prevalent. Little closed spaces, or bursce, to facilitate its movements, exist vmder the skin, at the joints, over the prominent points of the bones. Capillaries of the Cutis.—The cutis is a very vasadar organ—that is, it is very abundantly supplied with bloodvessels. The arteries immediately below the skin break up into a number of very minute capillaries, which ramify through the meshes in the areolar tissue, forming a very close vascular network. These capillaries lie so close to each other, and are so abundantly sup- plied with blood, that it is impossible even to insert the point of I a fine needle into the cutis without rupturing their walls and