Although progressive lenticular degeneration, first described under that title by S. A. K. Wilson1, is well established clinically, it has not often been encountered in this country. Since Wilson's first publication, in 1912, a number of cases have been recorded in foreign literature, but, with the exception of a case recently reported by Auer2 and some brief references made before the neurological societies of New York and Philadelphia, little or nothing on the subject has appeared in American literature.
The patients whose histories are recorded here were admitted at different times to the wards of the Orthopaedic Hospital and Infirmary for Nervous Diseases, Philadelphia, and first came under the care of Dr. S. Weir Mitchell, and later passed to the service of Dr. John K. Mitchell. They have both been under observation for a considerable length of time. Examinations have been made repeatedly by various observers, and all