202 PHYSIOLOGY AND HEALTH. 



which are placed (Fig. XXVI. c,c,e,) just beneath the skin; 

 and the perspired fluid is carried from each one of them to 

 the surface, through a minute tube which is attached to the 

 gland, and leads outward (Fig. XXVI. e?,f/,d,) There are three, 

 thousand five hundred and twenty-eight of these little tubes 

 on each square inch in the palm of the hand, and twenty- 

 eight hundred on each square inch throughout the whole 

 body, making seven millions of perspiratory tubes on a man 

 of average size. 



480. The power of relieving the body of its superfluous 

 matter or moisture by perspiration is not common to all ani- 

 mals.. Men and horses sweat, and thus find an outlet for 

 these matters, and for the excess of heat. But dogs have 

 no such means of relief; when they are heated by exercise, 

 they loll their tongues, and the evaporation from their sur- 

 face aids in the cooling process. Cattle, when heated in 

 the summer, effect the same purpose in the same manner. 



481. There are other secretions of the skin beside the 

 watery perspiration. The skin is soft and oily, it is supple, 

 and in health it is never dry and hard. To produce this 

 condition, there are numerous little glands placed within 

 the skin, whose business it is to gather out of the blood the 

 elements of an oily matter, and with them compound this 

 substance, and then throw it out upon the surface. If the 

 preparation of this oil is checked, the skin is dry and hard ; 

 but, when this work is well performed, the skin is soft and 

 supple; and pleasant to the touch. " It is this fluid which 

 soils the linen, and which causes the water to collect in 

 drops, when we come out of the bath." These oil-glands are 

 more abundant in the face and in other parts exposed to the 

 air, and in the arm-pits, &>c., where one part of the skin comes 

 in contact with another. But through all the skin there are 

 enough to keep the surface soft, and in a natural condition. 



482. This oily secretion is sometimes odorous, and in 

 some parts unpleasant to the smell, and even in some men 

 fetid. It is more so under the arms than elsewhere ; but in 

 some persons the whole surface throws out an offensive mat- 



