A short time since a gentleman was under my charge in whose case the only deviation from health which could be perceived was an utter inability to sleep. Being by profession a broker, and passing his days, and a great portion of his nights, in the stock and gold rooms, during a period of great financial excitement, his brain had been kept so continually in a state of intense action that it was impossible for him, when he went to bed, to compose his mind so as to allow of sleep ensuing. Thoughts similar to those which were excited during his business operations were in full flow, notwithstanding all his efforts to banish them. Calculations were entered into, and speculations were constantly being formed with as great or even greater facility than during the day. Many of the latter were of the most extravagant character, a fact of which he was fully aware at the time, but he nevertheless found it impossible to refrain from indulging in them. All his other functions were performed with regularity. His appetite was good, he took a not inconsiderable amount of exercise, and he committed no excesses of any kind except as regarded his brain. When I first saw him he had not slept for six nights, although he had taken large quantities of brandy, morphine, and laudanum; but beyond a slight feeling of confusion in his mind at times, and a little pain in his eyeballs, he experienced no unpleasant sensations during the day. As soon, however, as his head touched the pillow, and he tried to get to sleep, a feeling of the most intense uneasiness came over him, while at the same time his face and ears became hot and flushed. His mental faculties were roused into increased action; he tossed restlessly from one side of the bed to the other, and by the time morning came he was thoroughly exhausted, mentally and physically. A cold bath and a breakfast of two large cups of coffee, beefsteak and eggs, set him up for the balance of the day, till he retired to bed, when the phenomena of the previous night would be repeated.