The older asylum physicians paid great attention to the psychological precursors of mental disorder, just as the public still does, following a true instinct. We accepted this hint and carefully investigated the previous psychological history wherever possible. Our trouble was richly rewarded, for we often found, to our surprise, that the disease broke out at a moment of some great emotion which, in its turn, had arisen in a so-called normal way. We found, moreover, that in the mental disease which ensued a number of symptoms occurred which it was quite labour in vain to study from the morphological standpoint. These same symptoms, however, were comprehensible when considered from the standpoint of the individual's previous history. Freud's fundamental investigations into the psychology of hysteria and dreams afforded us the greatest stimulus and help in our work. A few instances of the latest method in psychiatry will make the subject clearer than mere dry theory. In order to bring home to you the difference in our conception I will first describe the medical history in the older fashion, and subsequently give the solution characteristic of the new departure. The case to be considered is that of a cook aged 32; she had no hereditary taint, was always industrious and conscientious, and had never been noticeable for eccentric behaviour or the like. Quite recently she became acquainted with a young man whom she wished to marry. From that time on she began to show certain peculiarities. She often spoke of his not liking her much, was frequently out of sorts, ill-tempered, and sat alone brooding; once she ornamented her Sunday hat very strikingly with red and green feathers, another day she bought a pair of pince-nez in order to wear them when she went out walking with her fiancé. One day the sudden idea that her teeth were rather ugly would not let her rest, and she resolved to get a plate, although there was no absolute need. She had all her teeth out under an anæsthetic. The night after the operation she suddenly had a severe anxiety-attack. She cried and moaned that she was damned for ever, for she had committed a great sin; she should not have allowed her teeth to be extracted. People must pray for her, that God might pardon her sin. In vain her friends attempted to talk her out of her fears, to assure her that the extraction of teeth was really no sin; it availed nothing. At day-break she became somewhat quieter; she worked throughout the day. On following nights the attacks were repeated. When consulted by the patient I found her quiet, but she wore a rather vacant expression. I talked to her about the operation, and she assured me it was not so dreadful to have teeth extracted, but still it was a great sin, from which position, despite every persuasion, she could not be moved. She continually repeated in plaintive, pathetic tones, "I should not have allowed my teeth to be extracted; oh yes, that was a great sin which God will never