"Collapse delirium" was first described by Hermann Weber in 1866. It takes the form of a stuporous state with confusion of thought, dreamy hallucinations, flight of ideas, an unstable emotional condition and an active motor excitement. The onset is usually sudden, following a period of sleeplessness and restlessness. Disorientation occurs early and consciousness is markedly clouded. Phantastic hallucinations and illusions are frequent. Excitement and confusion are also prominent symptoms. Flight of ideas is common and the patient often sings or expresses himself exclusively in verse or rhymes. Senseless and rapidly changing delusions are noted. The mood is elated, erotic, anxious or irritable, with outbursts of anger. Motor excitement is conspicuous and there is no sleep. Usually food is refused and nutrition disturbed with a great reduction of bodily weight. This condition is of short duration, usually not more than a few days, often terminating in sleep in favorable cases. Only a confused recollection of events remains on recovery. Collapse delirium, according to Kraepelin, is purely an infectious process and often occurs in pneumonia, erysipelas and influenza, following the subsidence of the active symptoms of the disease. It occasionally complicates articular rheumatism and scarlet fever. The characteristic features in erysipelas are hallucinations and delusions of a delirious type, while clouded states, confusional excitements and flight of ideas are more common after pneumonia. The symptoms usually develop after the temperature falls and other evidences of weakness are present. Kraepelin, however, recognizes infection as the only cause at this time, although he previously described these as exhaustive conditions.