I make no apology for writing this book. I think it will satisfy, in some measure at least, a professional need. If not, if it contain no little grain of thought worthy of perpetuation, no ray of knowledge to help brighten that dawn of reason with which, some profess to believe, the hilltops are already aglow, let its extinction vindicate the Darwinian law. In one respect at least—the grouping and classification of my subjects—I hope to meet the approval of my professional brethren; and, entering upon the discussion of themes which writers at the beginning of the past century barely rescued from the misty domain of poetry and romance, but which were somewhat better amplified and analyzed by others of the Ploss-Bartels school, I do so with the earnest assurance that in the following pages, while startling facte shall be dealt with in very plain language, while my preaching—like that of Nathan to King David—will be very concise, and to the point, I shall endeavor to show that, until the law learn to recognize and discriminate between conscious crime and physical disease, between deliberate violation of statutory enactments and those irresponsible, paranoiac acts which are but the evolution, or involution, of the psychologically perverted organism, the need of the medico-legal writer will not cease to exist; and in doing this, I beg at the very outset to acknowledge my indebtedness to those authors, ancient and modern, whom I have so freely used, with proper credit in each case; as well as to the professional friends, of both sexes, who have so materially and kindly aided me in investigations which were not only tediously technical, but, as I have intimated, unusually delicate in their nature.

J. Richardson Parke.

925 Spbuce Street, Philadelphia.