Huntington's chorea is said to have been referred to first by C. O. Waters of Franklin, N. Y., in Dunglison's "Practice of Medicine" in 1842. An article on the subject by Irving W. Lyon also appeared in the _American Medical Times_ in 1863. The name by which the disease is now generally known was the result of an elaborate description of its symptomatology by George Huntington in the _Medical and Surgical Reporter_ in 1872. He particularly called attention to the fact that it is hereditary in origin, occurs in adult life, is associated with suicidal tendencies and often exhibits mental symptoms. On the important subject of heredity Huntington made the following observation: "If one or both of the parents have shown manifestations of the disease, and more especially when these manifestations have been of a serious nature, one or more of the offspring almost invariably suffer from the disease if they live to adult life; and if by any chance these children get through life without it, the thread is broken and the grandchildren or great grandchildren may rest assured that they are free from the disease. Unstable and whimsical as the disease may be in other respects, in this it is firm; it never skips a generation to manifest itself in another; as soon as it has yielded its claims, it never regains them." A well known monograph on the subject by Osler appeared in 1894. McCarthy[189] refers to the mental condition associated with this disease as "a severe and gradually progressive deterioration, ultimately ending in absolute dementia. In some cases the mental defect is noted from the onset of the symptoms, in others the mentality may remain unimpaired for years. Mental deterioration is the rule, and it is associated with a loss of memory and a tendency to self-destruction which gradually develops. When the mental degeneration is well marked, outbreaks of violence are sometimes noted. In one of the writer's patients, as the disease progressed, the clinical picture of paresis was presented. The chronic delusional state is more often noted than would be inferred from Huntington's description." Hamilton,[190] who made a clinical study of a considerable series of cases in 1907, expressed the opinion that mental deterioration occurs in the majority of instances before the onset of choreiform symptoms. He found a special tendency to deterioration in the cases appearing early in life, while irritability and delusional ideas were more often observed in those developing in later years. Delusions of persecution and deterioration, however, were symptoms more or less common to both groups. Diefendorf,[191] in a study of twenty-eight cases in 1908, called attention particularly to the irritability with occasional outbursts of violence as well as attacks of despondency. He emphasizes emotional deterioration and indifference.