Although the occurrence of gastric sarcoma was observed more than thirty years ago, it has only recently been recognised that it constitutes an important, and by no means an infrequent, variety of malignant disease of the stomach. This opinion is founded partly upon the discovery that many specimens which are described in museum catalogues as carcinomatous or fibroid tumours present the characteristic features of sarcoma when examined by the microscope, and partly upon the large number of cases of sarcoma of the stomach that have been published since special attention has been directed to the subject. Thus, Perry and Shaw found four instances of this morbid condition among fifty specimens of malignant disease of the stomach, while in the course of twenty-three consecutive autopsies upon persons who had died from primary neoplasms of the organ we observed two examples of round-cell sarcoma. It may also be noted that whereas in 1897 Schlesinger was able to collect only thirty cases of the disease, in November 1900 the number of recorded instances exceeded sixty, of which fifty-three at least may be regarded as genuine. Although it is impossible to make any absolute statement as to the relative frequency of the complaint, it is probable that the sarcomata constitute from 5 to 8 per cent, of all primary neoplasms of the stomach. Six varieties have been described up to the present time, namely, round-celled sarcoma, spindle-celled sarcoma, fibro-sarcoma, myo-sarcoma, myxosarcoma, and angio-sarcoma. Of these the spindle-celled and the fibro-sarcomata are probably identical, while the single example of myxo-sarcoma appears to have been originally a case of the round-celled type, which had undergone degeneration.