(1) Fat.--(_a_) Inside fat, around the internal organs, usually called kidney fat, or suet. (_b_) Outside fat, next the skin, called caul fat. (2) Bone, (3) muscle, or lean meat. 3. Composition of fat: (1) Connective tissue, (2) true fat, (3) water. Fat should be the first part studied, because it is the simplest tissue and the parts are most plainly seen. Pick the specimen apart, and the tissue that holds it together is found. Its name is easily developed from its use. The water may be shown by heating pieces of fat in a small saucepan and, when it becomes hot, covering the dish with a cold plate. Remove the plate before it gets heated, and moisture will be condensed on its surface. The presence of water in fat may also be reasoned out by remembering that water enters into the composition of all body tissues. 4. Composition of bone: (1) Mineral matter (lime), (2) connective tissue, (3) water. Neither the mineral substance nor the connective tissue in bone can be seen until either one or the other is eliminated. Strike the fresh bone with a steel knife, and it shows the quality of hardness. Bones are built from food, and the only food substance that is so hard is mineral matter. Show the burned bone, with only the mineral matter left, and let each pupil examine it. Its formation indicates the spaces which the part burned out of it occupied. Let it fall or crush part of it in the fingers, to show how easily it is broken. Such bones would be no use as a framework to support the body. The bones of very old persons get too much like this, and we are afraid to have such people fall. The burned bone needs something to hold it together--a connective tissue. Such a tissue was in the spaces before the bone was burned. Show the bone after it has been prepared in an acid solution, with only the connective tissue left. Explain how it was prepared. Bend it to show its pliability. To be of use in the body it needs some substance to make it hard and rigid--the mineral matter which was dissolved out. NOTE.--This is an excellent time to show the necessity for bone-building mineral in the diet of babies and young children. If they do not get this mineral substance during the growth period, they cannot have hard, rigid bones, and their bodies are apt to become misshapen--bow legs, curved spines, etc. This substance is also necessary for hard, sound teeth. Draw attention to the fact that the mineral matter in milk and eggs is in solution, and therefore ready to be used by the body. Mineral matter is not in solution in bone, and cannot be dissolved by the digestive process, therefore it is practically of no use as food.