artificial experimentation, I mean, with physical instruments, and measurements. A rapid glance at Professor Thorndike's table of contents might lead one to set him down as not belonging to the experimental class of psychologists. He ignores the various methods of proving Fechner's psycho-physic law, and makes no reference to chronoscopes, or to acoustical or optical technics. Yet in another and psychologically in a more vital sense his book is a laboratory manual of the most energetic and continuous kind.

When I first looked at the proofs and saw each section followed by a set of neatly numbered exercises, problems, and questions in fine print, I confess that I shuddered for a moment. Can it be, I thought, that the author's long connection with the Teachers College is making even of him a high-priest of the American "textbook" Moloch, in whose belly living children's minds are turned to ashes, and whose ritual lies in text-books in which the science is pre-digested for the teacher by every expository artifice and for the pupil comminuted into small print and large print, and paragraph-headings, and cross-references and examination questions, and every other up-to-date device for frustrating the natural movement of the mind when reading, and preventing that irresponsible rumination of the material in one's own way which is the soul of culture? Can it be, I said, that Thorndike himself is sacrificing to machinery and discontinuity?

But I had not read many of the galleys before I got the opposite impression. There are, it is true, discontinuities in the book which might slightly disconcert a critic with a French turn of taste, but that is because of the intense concreteness with which the author feels his subject and wishes to make his reader feel it. The prob

lems and questions are uniquely to that end. They are laboratory work of the most continuous description, and the text is like unto them for concreteness. Professor Thorndike has more horror of vagueness, of scholastic phrases, of scientific humbug than any psychologist with whom I am acquainted. I defy any teacher or student to go through this book as it is written, and not to carry away an absolutely first-hand acquaintance with the workings of the human mind, and with the realities as distinguished from the pedantries and artificialities of psychology. The author's superabounding fertility in familiar illustrations of what he is describing amounts to genius. I might enter into an exposition of some of the other peculiarities of his treatise, but this quality of exceeding realism seems to cap the others and to give it eminence among the long list of psychology-books which readers now-a-days have to choose from.

It is not a work for lazy readers, however; and lazy reading also has a sacred place in the universe of education. But I seem to foresee for it a powerful antipedantic influence, and I augur for it a very great success indeed in class-rooms. So, with no more prefatory words, I heartily recommend it to all those who are interested in spreading the knowledge of our science.

WILLIAM JAMES.

Harvard University.

PREFACE

The aim of this book is to help students to learn the general principles of psychology. Those facts which

can most profitably be made the subject matter of a course in general psychology are presented with an abundance of concrete illustrations, experiments, exercises and questions, by which the student may secure real rather than verbal conceptions and may test, apply and make permanent his knowledge.

A good method of studying the book is probably (1) to read a section through quickly, then (2) to read it with care, jotting down in a note book every question that seems to be answered by the text. Next (3) without the book try to answer those questions; hunting out the answers when unable to give them from memory. (4) Do the printed exercises, writing down each answer or, if it is too long, its main point. (5) Do any experiments in connection with the section. (6) When the several sections of a chapter have all been thus studied, write down the general questions which the whole chapter has answered, and after an interval of several days try to give clear and reasonably adequate answers to these questions in writing.

The references for further reading noted at the end of each chapter may best be read only after the text itself is mastered. The references marked A are for students in general, those marked B are for students especially desirous of increasing their knowledge of psychology and capable of studying difficult treatises. Additional read

ings on special topics will be found at the end of the book. In the references Roman numerals refer to the chapters. § 1, § 2, § 3, etc., refer to sections. Arabic numerals alone refer to pages.

Through the great kindness of Professor L. F. Barker of Chicago University, Professor Dr. L. Edinger of Frankfurt-a.M., Professor A. von Kölliker of Würzburg, Professor M. v. Lenhossék of Budapest, Professor M. Allen Starr, Dr. E. Leaming and Dr. O. S. Strong of Columbia University, and Professor A. Van Gehuchten of Louvain, I am able to reproduce photographs and drawings of the finer structure of the nervous system such as are rarely seen in elementary books on either psychology or physiology.

To Professor William James I owe the common debt of all psychologists due for the genius which has been our inspiration and the scholarship which has been our guide. The obligation is patent in every chapter. Indeed, the best service I wish for this book is that it may introduce its readers to that masterpiece of thought and expression, the Principles of Psychology. I owe also a personal debt for unfailing kindness and encouragement which can only be acknowledged, never repaid.

PREFACE FOR TEACHERS

This book is designed to serve as a text-book for students who have had no previous training in psychology, who will not in nine cases out of ten take any considerable amount of advanced work in psychology, and who need psychological knowledge and insight to fit them to study, not the special theories of philosophy, but the general facts of human nature. For such students training in methods and technique alone is almost futile: they are not to be expert psychologists, but intelligent men and women. Training in the analysis of the process of thought is equally inadequate: they need more than an introduction to logic and philosophy. A course which reduces psychology to a mass of technical words and definitions is criminal: it hides realities from the student and either encourages him in verbal quibbling or destroys all interest in the study of mental facts. It is the right and the duty of the psychologist as a thinker to specialize, to be an experimentalist, or analyst, or comparative psychologist. But it is the right of the student in a general course on psychology to demand a fair representation of the science as a whole. This book is therefore eclectic in

subject matter and in method. Description, definition, analysis, experimentation, comparative and genetic studies -no one of these can wisely be omitted.

This book represents no particular kind of psychology peculiar to the author, nor any radical departures from the general usage of modern text-books on psychology.