MOTHER: There are some little holes in the skull, and through these twenty-four branch lines pass, carrying the nerves all over the face and head. One pair find their way to the nose, and they tell the master of the house how things smell. Another pair reach to the eyes, and tell him how things look. They are nerves of sight. There are three pairs to tell the muscles of the eye how to move. One pair passes to the ears, and are called nerves of hearing. The others are scattered all over the face, passing to the teeth, tongue, and throat, and even to other parts of the body. This picture shows the brain as the main office, the cord or cable in the back-bone, and how the branches extend to all parts of the body. Still there are thousands of smaller lines which can not be seen at all. HELEN: And what sends the messages to and from the brain over the nerves, mother? MOTHER: The power which sends them is called “nerve force,” though what it is even the wisest men do not know. We can stop it by pressing on the nerves, just as you can stop the current of the telegraph. We sometimes say that our leg or arm is “asleep.” If we try to move, it gives us pain, or it may be we can not move at all. One nerve runs along the back side of the arm over the elbow. If we hit the elbow, it makes the arm and hand feel numb. We say the “funny bone,” or the “crazy bone,” is hurt, but it is not the bone at all, but the nerve. AMY: I heard a lady who is ill say she wished she had no nerves. Why do we have them? MOTHER: I think we have already learned how useful they are to carry messages for us. We would be quite helpless without them, for the brain sends word over them every time we move any part of the body. Another reason is they watch for our welfare. If we are cut or burned, it gives us pain. We don’t like the pain, so we are more careful when we use sharp tools or go near the fire. If you touch the hot stove, you jerk away your hand. “I’m burnt,” the finger sends word to the brain. The brain sends back the message, “Get off the stove, quick.” And to the nerves of the eye it says, “See if it is blistered.” To the face muscles, “Make up a wry face to show how badly it hurts.” To the feet and hands, “Get some cold water to put the burned finger in.” To the tongue, “Tell your mother about it.” All these messages are sent at the rate of one hundred feet a second, and the eye, face, hands, feet, and tongue all feel sorry for the burnt finger, and do all they can to help it. [Illustration: “_Tell your mother about it._”] Every part of the body, the bones, muscles, stomach, heart, and lungs, has these useful little nerves to let the master know when anything is wrong with them. ELMER: Do the nerves ever get sick, mother?