The fourth edition appeared in 1902, when this work had already increased considerably in size. Since this date only a few new data and new views have been brought to light, and therefore I have found it necessary to make only a few additions and alterations in the book. The most important publications on this subject have appeared in the Zeitschrift fur Hypnotismus (now called Journal fur Psychologic and Neurologic), edited by Dr. Oscar Vogt (Leipzig: Amb. Barth). In recent years practically nothing has been done which has directly furthered the development of the doctrine of suggestion. On the other hand, Semon's theory of the "Mneme" is of importance. Dubois' views have created a considerable sensation, I shall return to this in Chapter VII (Hypnotism And Psychotherapy).

Chapter I (Consciousness And The Hypothesis Of Identity (Monism)) and § 16 of Chapter IV are of theoretical nature. They require more effort and psychological deliberation than the rest They are, however, not absolutely indispensable. Still those readers who will expend the energy in carefully reading and understanding it will grasp hypnotism, not only half or superficially, but fully.

In the fifth edition a new chapter (No. X), on "A Case of Double Consciousness," has been added. Chapters IX, XII, XIII, XIV, and XV have remained unaltered. Numerous additions and alterations have bad to be made in Chapters III, IV (§§ 2 and 5), VI, and VII, while only a few were made in the remaining chapters and in the remaining paragraphs of Chapter IV.

DR. AUG. FOREL.

CHIGNT, near MORGES.