The patient, aet. 27 years, received in one of the battles near Sedan, during the Franco-Prussian war, a bullet wound which fractured the left parietal bone. His right arm was almost immediately paralyzed; after a few minutes the paralysis involved the right leg, and he lost consciousness. It was only after the lapse of three weeks that he recovered his senses. He was finally taken to Paris, where the paralysis gradually disappeared. From a period some three or four months after the reception of the injury, he began to manifest periodical attacks of somnambulism, at intervals of fifteen to thirty days with an average duration of fifteen to thirty hours. During the whole of this time his life presented two essentially distinct phases--the one normal, the other pathological. In the normal condition he was able to gain a livelihood. He had been a clerk in several houses, a singer in a _café_, and while in the hospital had made himself useful and agreeable. The somnambulic attacks which he experienced were characterized by an instantaneous onset, resulting in the abolition of all his senses except the tactile sense. Sight was perhaps partially persistent, for on many occasions he seemed to be impressed by brilliant objects, but he was obliged to employ the sense of touch in order to understand their form, volume, etc. During all these crises his gait was easy, his attitude calm, his countenance peaceful; his eyes were widely open, with dilated pupils; the forehead and brows were contracted; there was an incessant nystagmus, indicating a disordered state in the brain; he was continually mumbling or muttering. When walking in a familiar locality he moved with perfect freedom; but if in a strange place, or if obstacles were placed in his way, he examined the obstructions by feeling of them with his hands, and turned easily aside. If any attempt was made to change his direction, or to quicken or retard his pace, he allowed himself to be directed like a mere automaton, continuing to walk in any way thus chosen for him. He would also eat, drink, smoke, dress himself, walk out, and retire to bed as usual. These processes seemed to be effected as a result of previous habit, without any actual consciousness or feeling. He ate voraciously without discernment, and drank in the same manner ordinary wine, wine of quinine, water, assafœtida, without exhibiting any evidence of sensation whatever.