An important diagnostic aid which can give much preoperative information with regard to operability of lesions of the stomach is the roentgen ray. It can demonstrate the size, the shape and the position of the stomach, important factors with which the surgeon has to reckon, as well as the size, the location and the extent of the lesion. It can show whether a stomach suspected of disease is normal, whether a tumor is present, and whether the tumor is intrinsic or extrinsic. The roentgenologist, by basing his judgment on the sum of knowledge gained from the roentgen ray, can point out whether a cancer or lesion of the stomach is operable or not, so far as the stomach is concerned; but it remains for the internist and the surgeon to advise operation and fof the surgeon to decide on the kind of operation. The earlier the lesion is discovered, the