21/21 The brain uses the nerves very much as a man uses the telephone or telegraph wires. With the large brain we remember, think, and reason. The little brain does the simple kind of thinking, by means of which the heart, lungs, and other vital organs are kept at work even when we are asleep. The spinal cord does a still more simple kind of work. It enables us to walk and to do other familiar acts without using the large brain to think every moment just what we are doing.. |