A lady, about forty-five years of age, the mother of many children, has been troubled during the course of the past year with violent palpitations of the heart, and great difficulty of respiration, especially on going up stairs. These complaints have lately increased, so that she has kept in her chamber about two months. Her countenance is florid; her eyes are clear and bright. She has dizziness, especially on moving, without pain in her head. She had for some time, a severe cough, which is now relieved. The dyspnœa is not yet very distressing, except on using motion; it often occurs in the night, and obliges her to rise and sit up in bed. The palpitations are very hard, and so strong, that they may be perceived through her clothes; the tumult in the thorax is indescribable. The functions of the abdominal viscera are unimpaired. The pulse is hard, vibrating, irregular, intermittent, very variable, corresponding with the motions of the heart, and similar in each arm. There is not yet the slightest reason to suspect any dropsical collection. The alternations of ease and distress are very remarkable, but on the whole, the violence of the symptoms increases rapidly. There is no difficulty in discovering in this case an organic disease of the heart, which probably consists in an enlargement and thickening of the heart, and an ossification of the semilunar valves of the aorta. CASE X. Levi Brown, a cabinet-maker, forty-eight years of age, complained in February, 1809, of great difficulty of breathing, and an indescribable sensation in the chest, which he said was sometimes very distressing, and at other times quitted him entirely. Being a man of an active mind, he had read some medical books, whence he got an idea, that he was hypochondriac.