The literature of medicine contains many references to acute chorea. It was referred to, according to Paton, by Plat as early as 1614 and was discussed by Sydenham at some length. Wharton Sinkler, in describing chorea in Pepper's "System of Medicine" in 1886, made the following interesting remarks on the mental changes involved:—"The child is irritable and feverish, cries and laughs readily, or is sullen and morose. Sometimes he is violent to those about him but this is rare. Intellectually the patient suffers somewhat. He is not able to study as before, and the memory may be impaired. Sometimes there is a mild form of dementia." Burr[206] divides these conditions into four groups:—"First (and this includes the vast majority), patients in whom there is peevishness, fretfulness, some loss of the power of fixing the attention, and a slight loss of the moral sense shown by disobedience and selfishness. Second, those showing in addition to the above symptoms, night terrors, and transitory, visual, auditory, or other hallucinations. Third, those with distinct delirium, wild or mild, accompanied with fever. Fourth (and this group is very small when we remember how common chorea is), those showing stupor, or rather stupidity, and an acute dementia, which may follow the condition described under three, or appear without any preceding mental symptoms at all severe, and which is usually accompanied with trouble on articulation not caused by choreic movements of the lips and tongue, but the result of mental hebetude." White[207] refers to the irritability and emotional instability of choreics and describes a psychosis in "chorea insaniens" characterized by an acute confusion, sometimes of a violent type with hallucinations, or a paranoic condition with delusions of persecution. This may develop into a stuporous state. Kraepelin describes the psychotic manifestations of acute chorea as forms of delirium due to infection with characteristic states of clouding, confusion, etc. Wechsler has expressed similar views.