An intensive study of the motor and secretory functions of the stomach following surgical intervention has established various facts, which I present here. They will prove of value by bringing about active discussion and constructive criticism, and thus lead to other helpful researches in the field of those intricate and often discouraging problems which arise from an operative procedure which has failed to bring about the desired alleviation of organic and functional disease in the gastroduodenal area. This study has embraced a series of sixty-seven cases, and the results encourage me to believe that various symptoms may now be more correctly interpreted, and prognosis facilitated. In the cases included in the series, the length of time following operation varies from ten days to fourteen years, the various types of operation being distributed as follows: gastro-enterostomy, thirty; pyloroplasty, twenty-two; closure of perforated ulcer, two; resection, three; gastroduodenostomy, two; gastrectomy (partial), one;