Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1880 edition. Excerpt: ...scales (cuticle); (J) a cortical substance made of coloured horny matter; and finally (c) the medulla or pith, which is absent in some hairs. The bulb of the hair rests upon and overlies an elevation of the follicle (papilla), which is composed of undeveloped nucleated connective tissue corpuscles, and a few fibres. The sheath of the hair is divided into (a) internal, of two layers of large cells, the external layer consisting of transparent oval cells without nuclei, and the other layer of polyhedral nucleated cells; (b) external, of a variable number of layers of cells, becoming more columnar externally. The hair follicle consists of an involution of the cutis vera, forming three layers: (a) external is very thin, made up of longitudinally arranged connective tissue bundles, with fusiform nuclei and elastic fibres; (J) middle is thicker, and made up of transverse, undeveloped fibrous tissue, with rodshaped nuclei; (c) internal, of a thin, striated, transparent membrane of endothelial cells. To the outside of the follicles thin bundles of unstriped muscular fibre are attached, and into the follicle open the ducts of sebaceous (simple tubular) glands generally one on each side. NAILS. Preparation. Sections may be cut of the end of a finger after hardening. Structure. Nails are composed of flattened epithelial scales, and are equivalent to the superficial or horny layer of the epidermis. The deeper layers of the nail are softer than the more superficial. Underneath the nail are highly vascular papillae (bed or matrix). Posteriorly it is received into a groove in the skin (root). The growth of the nail is effected by constant additions of cells to the root and under surface, so that it grows in length and in thickness at the same time....
