630. The OIL-GLANDS are small bodies imbedded in the true skin. They connect with the surface of the skin by small tubes, which traverse the cuticle. In some parts, these glands are wanting; in others, where their office is most needful, they are abundant, as on the face and nose, the head, the ears, &c. In some parts, these tubes are spiral; in others, straight. These glands offer every shade of complexity, from the simple, straight tube, to a tube divided into numberless 289 ramifications, and constituting a little rounded tree-like mass, about the size of a millet seed.
Of what are they a part? 630. Describe the oil-glands. With what do they connect? Do they exist in every part of the body? Of what form are their tubes?
631. In a few situations, these small glands are worthy of particular notice, as in the eyelids, where they possess great elegance of distribution and form, and open by minute pores along the lids; in the ear-passages, where they produce that amber-colored substance, known as the ce-ru´men, (wax of the ears,) and in the scalp, where they resemble small clusters of grapes, and open in pairs into the sheath of the hair, supplying it with a pomatum of Nature’s own preparing. The oil-tubes are sometimes called the se-ba´ceous fol´li-cles.
Fig. 115.
Fig. 115. 1, An oil-tube and gland from the scalp. A, The gland. B, The tube slightly twisted.
2. An oil-tube and gland from the skin of the nose. The gland (A) is double, and communicates with the main tube (B) by means of two smaller tubes.
3. Another oil-tube and gland from the nose. A, The gland. B, The tube filled with the peculiar animalculæ of the oily substances. Their heads are directed inward.
4. A small hair from the scalp, with its oil-glands. The glands (A) form a cluster around the shaft of the hair-tube, (C.) These ducts open into the sheath of the hair, (B.) All the figures, from 1 to 4, are magnified thirty-eight diameters.