INTRODUCTION. THE title "Factors of the Unsound Mind" will, I hope, convey to the minds of others the impression which is strong upon my own; that the Plea of Insanity in Criminal Cases-a subject as interesting in a scientific, as important in a practical, point of view is best examined under the strong light thrown upon it from this source. This being the idea which prompted the preparation of this work, I shall endeavour to realise it by taking these factors, one by one, submitting them in turn to careful examination, and condensing the results to which such examination leads, in short and simple statements. I shall then pass, in each case, from the statement of facts to the inferences they seem to warrant—to inferences having a direct bearing on the plea of insanity. If, as I think will happen, the inferences drawn in reference to the first factor are found to be in harmony with those drawn from the second, and those from the second with those from the third, and so on with the whole series, we may attain at last possibly to new truths, but certainly to a firmer conviction of the soundness of certain principles already established, and to greater confidence in the application of them to practice. I shall treat the several factors under distinct divisions or sections, forming collectively Part I. of this work; Part II. being devoted to the plea of Insanity. In Part I., the first factor, element, or constituent, of the unsound mind to which I shall invite attention is Illusion. Delusion will follow; then Dreams; then Somnambulism; then Delirium, Incoherent Speech, and Convulsive Movements; then the Emotions, Passions, and Movements of the Will. A section will also be devoted to mixed cases from causes of common occurrence; and a final chapter to a case of Religious Mania in which these leading factors of the unsound mind will be shown in simultaneous operation in the same person. The contents of Part II., and the subjects of the remaining sections, will be found sufficiently indicated in the concluding paragraph of the first section of the second part, to which the reader is referred. PART I. SECTION I.—ILLUSIONS. By an Illusion, I need scarcely say that I mean an involuntary sensation without corresponding external object. By this definition I exclude those voluntary creations of memory or fancy, not rare, I believe, in childhood, which, though full of interest as illustrations of sensations generated from within, have no direct bearing on my subject. Let me say, too, that as I have no use for the word Hallucination, and some objections to it, which I need not particularise, I shall not employ it. I shall use the one term Illusion, adding to it that I may not be misunderstood-the three words "of the senses"-Illusions of the senses; and where others employ the word "hallucination," I shall use what I deem a better term, "illusive transformation," on which, I think, I shall have something interesting and important to say. Need I add that I have no intention of misapplying the word Illusion to any object really seen, though at the time misunderstood, such as the "Giant of the Brocken," or any other kind or form of mirage? and that I shall not stop to take note of such trivial impressions on |