It is now generally known that the form of retinal detachment caused by typical disinsertion at the ora serrata (anterior dialysis) heals exceedingly well under proper diathermic treatment. This is the case even when the hole extends over more than one-fourth the circumference of the ora. I have operated in the last five years in 100 such cases with 100 per cent success, and I therefore look on this condition as extremely well suited for diathermic treatment. It is not my intention to discuss here the reason for this happy outcome. I wish merely to point out that the prognosis of the operative treatment of retinal detachment, with the exception of disinsertion, is worse in cases in which large holes are present than in those in which there are small ones (not exceeding 2 disk diameters). Although many other conditions may play an important rôle, detachment caused by