A system of obstetrics . lliiirx.—Every hair commences as an ingrowth of the Malpighianlayer of the epidermis, reaching down into the dermis as a solid rod ofcells. This rod dilates at its deeper end (E, Fig. 75), and then a vas-cular dermic papilla extends into it (F). Meanwhile, the primitivecontinuous cylinder (D) of epidermic cells divides concentrically into an 148 DEVELOPMENT OF THE EMBRYO. inner core and an outer epidermic sheath (E, F). The cells of the coreform the hair, which ultimately breaks through the horny layer of theepidermis and projects beyond it (Fig. 76). The cells of the

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A system of obstetrics . lliiirx.—Every hair commences as an ingrowth of the Malpighianlayer of the epidermis, reaching down into the dermis as a solid rod ofcells. This rod dilates at its deeper end (E, Fig. 75), and then a vas-cular dermic papilla extends into it (F). Meanwhile, the primitivecontinuous cylinder (D) of epidermic cells divides concentrically into an 148 DEVELOPMENT OF THE EMBRYO. inner core and an outer epidermic sheath (E, F). The cells of the coreform the hair, which ultimately breaks through the horny layer of theepidermis and projects beyond it (Fig. 76). The cells of the sheathgive origin to the lining of the hair-follicle. For the final structure ofthis and of the hair a treatise on histology must be consulted. The first rudiments of hairs may be detected toward the close of thethird month in the human embryo. They break through the hornylayer of the epidermis (Fig. 76) during the fifth month of intra-uterine Fig. 76

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Keywords: ., bookcentury1800, bookdecade1880, booksubjectobstetrics, bookyear1