The treatment of chronic progressive deafness in the past by any of the conservative measures has been so unsatisfactory that one is apt to grasp with enthusiasm any new procedure that gives a chance for improvement. Fistulization of the labyrinth has been known for many years to give immediate improvement of hearing in typical cases of otosclerosis or in other cases of chronic progressive deafness in which the bone conduction has remained good. The problem of the earlier experimenters in this field has not been so much one of obtaining improvement in hearing by operative means as it has been to maintain the improvement obtained. The surgical procedures used by Holmgren1 and Sourdille2 in the past few years have been successful in obtaining the desired improvement in many cases, but in apparently the great majority of such cases this improvement of hearing has been of short duration, the early regeneration