The case which I have just sketched is a simple one. It is transparent. My second example is somewhat more complicated. It is the case of a man between 30 and 40 years of age; he is a foreign archæologist of great learning and most unusual intelligence. He was a precocious boy of quite excellent character, great sensitiveness and rare gifts. Physically he was small, always weakly, and a stammerer. He grew up and was educated abroad, and afterwards studied for several terms at B----. So far there had been no disorder of any kind. On the completion of his university career he became zealously absorbed in his archæological work, which gradually engulfed him to such an extent that he was dead to the world and all its pleasures. He worked incessantly, and buried himself entirely in his books. He became quite unsociable; before, awkward and shy in society, he now fled from it altogether, and saw no one beyond a few friends. He thus led the life of a hermit devoted entirely to science. A few years later, on a holiday tour, he revisited B----, where he remained a few days. He walked a great deal in the environs of the town. His few acquaintances now found him somewhat strange, taciturn, and nervous. After a somewhat protracted walk he seemed tired, and said that he did not feel very well. He then remarked he must get himself hypnotised, he felt his nerves unsteady. On top of this he was attacked by physical illness, viz. inflammation of the lungs. Very soon a peculiar state of excitement supervened which led to suicidal ideas. He was brought to the asylum, where for weeks he remained in an extremely excited state. He was completely deranged, and did not know where he was; he spoke in broken sentences which no one could understand. He was often so excited and aggressive that it took several attendants to hold him. He gradually became quieter, and one day came to himself, as if waking out of a long, confused dream. He soon completely regained his health, and was discharged as cured. He returned to his home and again immersed himself in books. In the following years he published several remarkable works, but, as before, his life was that of a hermit living entirely in his books and dead to the world. He then gradually acquired the name of a dried-up misanthrope, lost to all meaning of the beauty of life. A few years after his first illness a brief holiday brought him again to B----. As before he took his solitary walks in the environs. One day he was suddenly overcome by a faint feeling, and lay down in the street. He was carried into a neighbouring house where he immediately became extremely excited. He began to perform gymnastics, jumped over the rails of the bed, turned somersaults in the room, began to declaim in a loud, voice, sang his own improvisations, etc. He was again brought to the asylum. The excitement continued. He extolled his wonderful muscles, his beautiful figure, his enormous strength.