As to the matter of development and cultivation by Use, we would advise that you begin gradually to train your mind to _reproduce_ the experiences of the day or week or month, at intervals, until you feel that you are developing a new power in that direction. Tonight, if you try you will find that you can reproduce but a very small part of today's happenings with any degree of clearness. How clearly can you image the places you have been, the appearances of the people you have met, the various details of persons and things which you perceived during the experiences of the day? Not very clearly, we dare say. Try again, and you will find that you will be able to add new details. Keep it up until you feel tired or think that you have exhausted all the possibilities of the task. Tomorrow, try it again, and you will find that the second day's experiences are more clearly reproduced in your mind. Each day should find you a little more advanced, until you get to a place where the normal degree of power is attained, when the advance will be slower. Then, at the end of the week, review its experiences. Do the same the following week. At the end of the month, take a hasty mental trip over the month's experiences. And so on. Exercise, in moderation, along these lines will work wonders for you. Not only will it develop the Representation, but your powers of observation and your general memory will be found to be improved. And, moreover, in "chewing the mental cud" you will think of many things of interest and importance in connection with your work, etc., and your general mental efficiency will be increased for the faculties of the mind are interdependent and share benefits with each other. CHAPTER VIII. ABSTRACTION As we have seen, the first stage or step in the process of Thought is that called Perception, which we have considered in the preceding chapter. Perception, as we have seen, is the process by which we gain our first knowledge of the external world as reported to us by the channels of sense. The Perceptive faculties interpret the material which is presented to us by the senses. Following upon Perception we find the processes resulting from the exercise of the group of faculties which are classified under the general head of Understanding. Understanding is the faculty, or faculties, of the mind by means of which we intelligently examine and compare the various _percepts_, either separating them by analysis, or else combining them by synthesis, or both, and thus securing our general ideas, principles, laws, classes, etc. There are several sub-phases of Understanding which are known to psychologists and logicians as: (1) Abstraction; (2) Conception or Generalization; (3) Judgment, and (4) Reasoning, respectively. In this chapter we shall consider the first of these sub-phases or steps of Understanding, which is known as "Abstraction."