Fig. 116. A perspiratory gland from the palm of the hand, magnified forty diameters. 1, 1, A twisted tube composing the gland. 2, 2, The two excretory ducts from the gland. These unite to form one spiral tube, that perforates the cuticle, (3,) and opens obliquely on its surface at 4. The gland is imbedded in cells filled with fat, which are seen at 5, 5.
What does fig. 116 represent?
635. “Could we need a stronger argument for enforcing the necessity of attention to the skin? On the pulps of the fingers, where the ridges of the sensitive layer of the true skin are somewhat finer than in the palm of the hand, the number of pores on a square inch a little exceeded that of the palm; and on the heels, where the ridges are coarser, the number of pores on the square inch was 2268, and the length of the tube 567 inches, 47¼ feet.
636. “To obtain an estimate of the length of tube of the perspiratory system of the whole surface of the body, I think that 2800 might be taken as a fair average of the number of pores in the square inch; and consequently, 700, the number of inches in length. Now, the number of square inches of surface in a man of ordinary height and bulk is 2500; the number of pores, therefore, 7,000,000; and the number of inches of perspiratory tube is 1,750,000; that is, 145,833 feet, or 48,611 yards, or nearly TWENTY-EIGHT miles!”—Wilson.
Give other computations in this paragraph. 635. What is said of the number of these pores on the pulp of the fingers? On the heels? 536. What is an average number of pores and length of tube of the whole surface of the body? Give the summary of the number of pores, and number or inches of perspiratory tube.
CHAPTER XXXII.
PHYSIOLOGY OF THE SKIN.
637. The skin invests the whole of the external surface of the body, following all its prominences and curves, and gives protection to all the organs it encloses, while each of its several parts has a distinct use.