THE causation of all psychopathic diseases can be referred to one fundamental instinct, the instinct of fear with its concomitant manifestation, the feeling of anxiety. one of the most primitive instincts of animal life. As Kipling puts it, Fear walks up and down the jungle by day and by night. Our life so well guarded by the protective agencies of civilization that we hardly realize the extent, depth, and overwhelming effect of the emotion of fear. rooted down deep in the very organization of animal existence, it takes its root in what the very essence of life,―the instinct of selfpreservation. Primus in orbe Deus fecit timor. We lead,” says Galton, “for the most part such an easy and carpeted existence, screened from the stern realities of life and death, that many of us are impelled to draw aside the curtain now and then and gaze for a while behind it.”1 “The progress from brute to man, says James, is characterized by nothing so much as by the decrease in frequency of proper occasion for fear. In civilized life in particular it has at last become possible for large numbers of people to pass from the cradle to the grave without ever having had a pang of genuine fear. Many of us need an attack of mental disease to teach us the meaning of the word. Hence the possibility of so much blindly optimistic philosophy and religion. The atrocities of life become ‘like a tale of little meaning though the words are strong'; we doubt if anything like us ever really was within the tiger's jaws, and conclude that the horrors we hear of are but a sort of painted tapestry for the chambers in which we lie so comfortably at peace with ourselves and the world. Be this as it may, fear a genuine instinct and one of the earliest shown by the human child.2