The diagnosis of developed chorea is not usually difficult. There are, however, occasional cases in which the symptoms are slight and doubtful and it is of some interest or importance to recognize the affection. Moreover, if chorea is an infectious disease, as is held probable by many, if not by most, neurologists, it is quite possible that our knowledge of all of its manifestations is not exhaustive. Any addition, therefore, is an advantage, especially if the symptoms noted are of diagnostic value. A peculiarity of the knee reflex in this disorder, described by W. Gordon1 in a recent article, appears to be such a one, consisting in a retardation of the relaxation of the contracting muscles; the foot is jerked up as quickly as ever, but does not fall at once to its former position. There are varying grades of this sustained contraction, from a very slight sluggishness in