From that time on the headaches manifested themselves in full severity, with hyperesthesia and death-like paleness and intense cold of the body. The early cultivation of the fear instinct resulted in a _neurosis_ with its recurrent states. Another patient is a man of thirty years; his family history is good. He is physically well developed, a well known professor of physics in one of the foremost institutions in this country. He suffers from attacks of loss of personality. The attack is of a periodical character, coming on at intervals of two weeks, occasionally disappearing for a few months, then reasserting itself with renewed energy and vigor. During the attack the patient experiences a void, a panic, which is sudden in its onset, like _petit mal_. The trouble was diagnosed as larval or psychic epilepsy; the man was referred to me by Dr. Morton Prince as an extremely interesting, but puzzling neurological case. Patient feels that his “self” is gone. He can carry on a conversation or a lecture during the attack, so that no outsider can notice any change in him, but his self is gone, and all that he does and says, even the demonstration of a highly complex problem in integral calculus is gone through in an automatic way. The fury of the attack lasts a few moments, but to him it appears of long duration. He is “beside himself,” as he puts it. He seems to stand beside himself and watch his body, “the other fellow,” as he describes it, carry on the conversation or the lecture. He is “knocked out of his body, which carries on all those complicated mental processes.” For days after he must keep on thinking of the attack, feels scared and miserable, thinking insistently, in great agony, over his awful attack, _a recurrent psychoneurotic phrenophobia_. At first the patient could trace this attack only as far back as his seventh year. Later on, earlier experiences of childhood came to light, and then it became clear that the _attack developed out of the primitive instinctive fear of early childhood_, fear of the unfamiliar, fear of the dark, of the unknown, of the mysterious, fears to which he had been subjected in his tender years. This state was further reinforced by the early death of his parents, it was hammered in and fixed by hard conditions of life, full of apprehension and anxiety. Life became to the child one big mysterious fear of the unknown. The fear instinct formed the pathological focus of the attack. As the patient puts it: “It is the mystical fear of the attacks which overpowers me.” With the disintegration of the focus the symptom complex of the attacks disappeared. The patient is in excellent condition, he is doing brilliant work in physics and chemistry and is professor in one of the largest universities in Canada.