Feeling deeply the want which has been spoken of, it seemed to me, early in my course, that something might be done toward remedying the deficiency, by preparing with care, and delivering to the classes, lectures upon the topics presented in the books, as they passed along. This course was adopted--a method devolving much labor upon the instructor, but rewarding him by the increased interest and more rapid progress of the pupils. Little by little the present work thus grew up, as the result of my studies, in connection with my classes, and of my experience in the daily routine of the recitation and lecture room. Gradually the lectures, thus prepared, came to take the place more and more of a textbook, until there seemed to be no longer any reason why they should not be put into the hands of the student as such. It is much easier to decide what a work on mental science ought to be, than to produce such a work. It should be comprehensive and complete, treating of all that properly pertains to Psychology, giving to every part its due proportion and development. It should treat the various topics presented, in a thorough and scientific manner. It should be conversant with the literature of the department, placing the student in possession, not only of the true doctrines, but, to some extent also, of the _history_ of those doctrines, showing him what has been held and taught by others upon the points in question. In style it should be clear, perspicuous, concise, yet not so barren of ornament as to be destitute of interest to the reader. At these qualities the writer has aimed in the present treatise; with what success, others must determine. All science, in proportion as it is complete and true, becomes simple. In proportion as this result is attained, the labor bestowed upon it disappears from view, and the writer seems, perhaps, to others, to have said but a very plain and common thing. This is peculiarly the case with mental science. The difficulty of discussing with clearness and simplicity, and, at the same time, in a complete and thorough manner, the difficult problems of Psychology, will be understood only by those who make the attempt. J. H. CONTENTS INTRODUCTION. CHAPTER I. PAGE ON THE NATURE AND IMPORTANCE OF MENTAL SCIENCE 15 SECTION I.--NATURE OF THE SCIENCE 15 SECTION II.--IMPORTANCE OF MENTAL SCIENCE 20 CHAPTER II. ANALYSIS AND CLASSIFICATION OF THE MENTAL POWERS 29 SECTION I.--GENERAL ANALYSIS 29 SECTION II.--ANALYSIS OF INTELLECTUAL POWERS 31 SECTION III.--HISTORICAL SKETCH--VARIOUS DIVISIONS OF THE MENTAL FACULTIES 35 DIVISION FIRST. THE INTELLECTUAL FACULTIES. PRELIMINARY TOPICS. CHAPTER I. CONSCIOUSNESS 39 CHAPTER II.