There are two points from which humanity may be viewed, the bodily and the mental. Hitherto, and for various reasons, medicine has concerned itself almost solely with the physical side of man. The result has been disappointing, for, necessary as it is to be acquainted with the bodily structure in health and in disease, the changes that occur in the latter only represent the physical results of a process, and not the means by which the damage is done. Now the duty of the physician is like that of the pilot; to bring his patient safely into port, availing himself of every agency with that one object in view. Therefore, Mind, in the fullest and widest sense, must be one of his chief studies.

In the summer of 1910 a symposium on the subject of Instinct and Intelligence was held in London at a joint meeting of the Aristotelian and British Psychological Societies and of the Mind association. Considerable interest in the discussion was shown both in the room in which we met and beyond its walls. The papers then taken as read, and subsequently published in the "British Journal of Psychology," disclose not a little divergence in the sense in which the terms instinctive and intelligent are used, an underlying divergence in the principles on which the proffered interpretations are based, and indications, more or less clear, of yet deeper-seated differences of philosophical foundation.

In the first three chapters of this book the elements of persuasion as a mental process are distinguished, and various forms of false persuasion in individuals and groups are described; it is shown how, from the very nature of the process involved, our persuasion of ourselves is only too apt to degenerate into self-deception, and how our persuasion of others may eaily assume the form of a deliberate attempt to exploit their mental or moral weaknesses. Chapter IV indicates how the tendencies of false persuasion may be counteracted, and on what lines persuasion may be rightly directed. Up to this point the subject is treated mainly in its psychological aspect. The subsequent chapters, which are closely related to, and follow naturally, the study of persuasion as a mental process, deal with persuasion more exclusively as a form of expression. In this part of the book special attention is given to such modern forms of propaganda as advertisements, newspapers, the cinematograph, the novel and the drama.