This is essentially a summary of a series of three articles on the "Radiographic Diagnosis of Gastroduodenal Lesions," the first two published respectively in the December, 1911, and the March, 1912, issues of theArchives of Roentgen Ray. The third will appear in an early issue of the same periodical. Two or three radiographs are sufficient to determine the size, shape and position of the stomach. For the convenience of indexing, the different types may be grouped into four classes: (1) cow-horn, (2) text-book, (3) drain-trap, (4) fish-hook (Figs. 1, 2, 3, 4); but in cases of suspected pathologic conditions one is not justified in making a diagnosis unless serial radiography is employed. This term is applied to a series of from fourteen to twenty-four radiographs of various phases of different cycles, which, when assembled, may be studied individually and collectively, or reduced to a cinematographic size and projected on