Exercise 2. Make an outline of this chapter. Exercise 3. Make an outline of some lecture. CHAPTER III BRAIN ACTION DURING STUDY Though most people understand more or less vaguely that the brain acts in some way during study, exact knowledge of the nature of this action is not general. As you will be greatly assisted in understanding mental processes by such knowledge, we shall briefly examine the brain and its connections. It will be manifestly impossible to inquire into its nature very minutely, but by means of a description you will be able to secure some conception of it and thus will be able better to control the mental processes which it underlies. To the naked eye the brain is a large jelly-like mass enclosed in a bony covering, about one-fourth of an inch thick, called the skull. Inside the skull it is protected by a thick membrane. At its base emerges the spinal cord, a long strand of nerve fibers extending down the spine. For most of its length, the cord is about as large around as your little finger, but it tapers at the lower end. From it at right angles throughout its length branch out thirty-one pairs of fibrous nerves which radiate to all parts of the body. The brain and spinal cord, with all its ramifications, are known as the nervous system. You see now that, though we started with the statement that the mind is intimately connected with the brain, we must now enlarge our statement and say it is connected with the entire nervous system. It is therefore to the nervous system that we must turn our attention. Although to the naked eye the nervous system is apparently made up of a number of different kinds of material, still we see, when we turn our microscopes upon it, that its parts are structurally the same. Reduced to lowest terms, the nervous system is found to be composed of minute units of structure called nerve-cells or neurones. Each of these looks like a string frayed out at both ends, with a bulge somewhere along its length. The nervous system is made up of millions of these little cells packed together in various combinations and distributed throughout the body. Some of the neurones are as long as three feet; others measure but a fraction of an inch in length. We do not know exactly how the mind, that part of us which feels, reasons and wills, is connected with this mass of cells called the nervous system. We do know, however, that every time anything occurs in the mind, there is a change in some part of the nervous system. Applying this fact to study, it is obvious that when you are performing any of the operations of study, memorizing foreign vocabularies, making arithmetical calculations, reasoning out problems in geometry, you are making changes in your nervous system. The question before us, then, is, What is the nature of these changes?