When necessity arises that makes a wide resection of the bladder peremptory, a large number of patients become solicitous as to what the function of the bladder will be after part of it has been removed. This solicitude arises so often that it is a striking feature, and it is because the urologist is assailed by this question that it has occurred to us that the function of the small bladder, or rather the regeneration of the bladder following resection, is important enough to merit consideration. The two lesions which most frequently require resections are carcinoma and elusive ulcer. If the lesions are treated by resection, it is imperative that the resection be very wide, and as a result a very small bladder is often left. This induces the frequent query on the part of the patient as to the ultimate outcome, from the point of view of the proper