I--the conscious self--dwell somewhere in this body, but where? When my finger tips touch the object I wish to examine, I seem to be in them. When the brain grows weary from overstudy, I seem to be in it. When the heart throbs, the breath comes quick, and the muscles grow tense from noble resolve or strong emotion, I seem to be in them all. When, filled with the buoyant life of vigorous youth, every fiber and nerve is a-tingle with health and enthusiasm, I live in every part of my marvelous body. Small wonder that the ancients located the soul at one time in the heart, at another in the pineal gland of the brain, and at another made it coextensive with the body! CONSCIOUSNESS WORKS THROUGH THE NERVOUS SYSTEM.--Later science has taught that the _mind resides in and works through the nervous system, which has its central office in the brain_. And the reason why _I_ seem to be in every part of my body is because the nervous system extends to every part, carrying messages of sight or sound or touch to the brain, and bearing in return orders for movements, which set the feet a-dancing or the fingers a-tingling. But more of this later. This partnership between mind and body is very close. Just how it happens that spirit may inhabit matter we may not know. But certain it is that they interact on each other. What will hinder the growth of one will handicap the other, and what favors the development of either will help both. The methods of their cooeperation and the laws that govern their relationship will develop as our study goes on. 5. PROBLEMS IN OBSERVATION AND INTROSPECTION One should always keep in mind that psychology is essentially a laboratory science, and not a text-book subject. The laboratory material is to be found in ourselves and in those about us. While the text should be thoroughly mastered, its statements should always be verified by reference to one's own experience, and observation of others. Especially should prospective teachers constantly correlate the lessons of the book with the observation of children at work in the school. The problems suggested for observation and introspection will, if mastered, do much to render practical and helpful the truths of psychology. 1. Think of your home as you last left it. Can you see vividly just how it looked, the color of the paint on the outside, with the familiar form of the roof and all; can you recall the perfume in some old drawer, the taste of a favorite dish, the sound of a familiar voice in farewell? 2. What illustrations have you observed where the mental content of the moment seemed chiefly _thinking_ (knowledge process); chiefly _emotion_ (feeling process); chiefly _choosing_, or self-compulsion (willing process)?