The "central office" of our Body Telephone System is just as important and just as necessary to keep in good working order. It would be very little use to have even the keenest of eyes and the sharpest of ears, with the readiest of nerve wires to carry their messages into the center of the body, unless we had some _organ_, or headquarters, there for switching the messages over to the nerves running to the right muscles to tell them what to do. If the brain-"Central" should fail in its duty, or get out of order, then the body would be in serious trouble at once. Every day we read in the papers of accidents because somebody didn't think, as well as see or hear. People see cars and automobiles coming, but don't give them a thought and so are run down and hurt. They hear the whistle of the engine at the crossing, but drive on just the same, without seeming to have heard it at all. They are absent-minded; the operator in the "central office" seems to be off duty, or busy about something else. But if we are going to get on in this world of cars and automobiles and all sorts of unexpected things, we must always "have our wits about us," as the saying goes, ready to send the messages out to the muscles in our legs and arms and fingers just as soon as any one of our "Five Senses" "rings up" the "Central" in our brain. Our body wires do not look at all like telephone wires; and the brain, if you could see it, would never suggest to you a central office. The nerves are fine white cords, the smallest ones finer than a hair, and the largest so big and strong that you could lift the body by it; and their branches run all over the body, to the muscles and the blood tubes and the skin and all the other parts, as the picture shows. You have already read how the skin can tell you when you feel warm and when you feel cold and when something hurts you. The brain is a soft wrinkled mass, partly gray and partly white. It is in the head; and because it is very soft and easily hurt, Mother Nature has put around it a strong wall, or shell, of bone--the _skull_, or brain box. Feel your head and see how very hard this bone is. Solomon, the Hebrew poet-king, called it the "golden bowl." I suppose he called it a "bowl" because it is round like one, and "golden" because it is so precious. People do not often grow well again if the "golden bowl" is broken or even cracked. [Illustration: THE NERVOUS SYSTEM--OUR BODY TELEPHONE The picture shows the brain, or "Central," and the thick nerve cord that runs down through the backbone, and the principal nerves of the back and the arms.]