An unusual clinical condition, which has not permitted definite classification, has been observed in two generations of a family, and there is definite history of the same disease in an earlier generation, making three generations in which the condition has appeared. FAMILY HISTORY The father (first generation) of the three men (secondgeneration) who now have the condition described died many years ago but is said by the sons to have had ulcération of the feetwith anesthesia and with loss of bone similar to that which afflicts the three sons. This man isreported to have had a brother who was afflicted in the same manner. None of the five daughtersof the man first mentioned gave a history of a similar condition. The father was married twice. One of the patients in the series to be described in the second generation was born of the first union, and two of the second union. Otherwise