Volume 2

Health lectures for the people.

Date:
1883-1892
Catalogue details

Licence: Public Domain Mark

Credit: Health lectures for the people. Source: Wellcome Collection.

    108/600 (page 96)
    layer of minute flat scales arranged upon the surface of the hair like the scales on the skin of a fish or a serpent. They are not disposed so regularly however, and they overlap each other like the tiles on the roof of a house, with this exception, that the overlapping takes place in an upward direction from the root to the point of the hair (Fig. 2). The free uncovered margins of the scales, therefore, look upwards, and when a hair is examined by a microscope, they show in the form of wavy lines, and at the 1 2 3 4 5 1 Fig. 3. Hair-rcct drawn away from the follicle. It shows how tlie upwardly directed scales on the surface of the hair-root are adapted to the downwardly directed scales which line the hair-folhcle. (From Henle's Anatomie des Menschen.) 1. Fihrous substance of the hair. 2. Scaly covering of the hair. 3. Scales lining the hair-follicle. 4 and 5. Wall of the hair-follicle. same time give the outline of the hair a slightly toothed or serrated appearance. This arrangement of the cuticular scales gives to hair a property of the very highest commercial importance. I refer to felting. Human hair is ill adapted for this purpose, because the scales lie too closely to the body of the hair; but wool, in which the 3cales stand well out, is peculiarly Avell suited for felting, in so