The human being is not only very wonderful, but he lives in a wonderful body. This body can do much and endure much. It is very perfectly adapted to its use. If man had not his reason to help him; if he did not walk upright when all other creatures crawl or go on all fours; if he did not differ from the lower animals in any other way than by having a thumb on each hand, he would still be superior to them. All the other large creatures are stronger than man, but his skillful hands, with their thumbs, make him master of them. These help him to grasp and to hold, to make things for his own use. He makes clothing to wear, houses to shelter himself, and weapons with which to defend himself. Hundreds of years ago there lived a great doctor, named Galen. He wrote one of the first books ever written about the human body, and he has left it on record that he was obliged to believe that God lives; for none but divine power could have made so wonderful a thing as the joint that turns the human hand at the wrist. Yet this joint is only one of the many wonderful things in the body. Now, to each of us is intrusted one of these bodies to take care of, that it may do our work for us. Our work is not just to live for ourselves, but to do something useful in the world; to help it all to be better because we are here. So you see how very much worth while it is that we should keep these useful bodies of ours as well and strong as we can. Besides the outer garments in which we clothe it, the body has a garment of its own. This garment is never laid aside; and though it is in constant use, it never wears out. We call it the _skin_. The skin is meant to protect the body. Lying close under it are many nerve ends, delicate blood vessels, oil glands, sweat glands, and other tiny organs that are too small to be seen without a microscope, but which are needed to keep the body in good order. In the pictures which are shown on this page, you will see how these tiny organs look when they are many times magnified. [Illustration: THE SKIN MAGNIFIED Fig. 1. Surface showing openings of pores. Fig. 2. Side view of sweat glands and pores. ] Now, like our outer clothing, this garment of the body needs to be kept very clean. You know that in this country when we take exercise, or, during the heat of the day, even without our taking exercise, the surface of the skin gets moist, little drops of water stand on it, and even run down our faces or make our hands wet. We call this moisture _perspiration_, and say that we are _sweating_ or _perspiring_ with the heat. The drops of water come from openings in the skin, which we call _pores_. These are little tubes connecting with sweat glands below the skin. You will see in the picture how these sweat glands look, and how the pores come to the surface.