Every school yard should be provided with swings, bars, and gymnasium apparatus to encourage the children to take plenty of exercise. Children who live in crowded towns need exercise during vacation as well as during school days, and the school yards should be open to them at all times. A summer teacher who shows the children the best way to exercise, has work fully as important as that of any other teacher during the school term. A sound body is more valuable than education itself, but a good education and a sound body together are the best assets any man or woman can have. =Questions.= 1. State the four things necessary to cure consumption; show the value of each. 2. What is the value of fresh air to every one? 3. How may an abundance of fresh air be secured in the home? 4. In the school? =Remember.= 1. Rest, fresh air, sunshine, and nourishing food are the cures for consumption. 2. All these things can be secured in any climate and by every person. 3. =Tuberculosis is a communicable disease.= 4. =Tuberculosis can be prevented.= 5. =Tuberculosis can be cured.= APPENDIX[4] A SUMMARY OF ANATOMY BONES AND JOINTS [Sidenote: The framework of the body] The framework of the body is composed of bones. There are 206 bones (not including the teeth) in the body. The bones of the body are divided into four classes--long bones, short bones, flat bones, and irregular bones. [Sidenote: Construction of bones] Regardless of their shape, all bones are composed in the same way. Every bone has an outer and an inner portion. The outer portion is a dense layer called _compact bone_. The inner portion is more open, and is much weaker; this is called _cancellated bone_ (from _cancella_, a sponge). In the smaller bones, the marrow, which is quite soft, runs through the spongy bone; in the larger long bones, the marrow is distinct and is enclosed by the spongy bone. [Sidenote: The periosteum] Every bone is covered by a thick, tough layer, the _periosteum_, which has three uses. When the bone is injured by disease or accident, the periosteum makes new bone to fill in and repair the break. It also builds new bone on the surface of the old as long as the body is growing. Finally, the periosteum gives strong and firm attachment to the muscles, which send tendons into it. [Sidenote: Joints] Every bone in the body (except the hyoid bone, to which the tongue is attached) is joined with some other bone. Most of them join with two or more bones. In most instances the end of a bone which joins with another is rounded off and made very smooth, so that it can slide easily over the other bone. There are three principal kinds of joints in the body. They are called the _ball and socket_ joint, the _hinge_ joint, and the _serrated_ or _saw-tooth_ joint. [Illustration: FIG. 77. The skeleton.] [Sidenote: The ball and socket joint]