Recently Wilder, Allan, Power and Robertson1reported a primary tumor of the pancreas which they proved conclusively to be a carcinoma arising from the islands of Langerhans, with metastases in the liver and lymph nodes. The patient suffered from hyperinsulinism, as indicated by the extremely low blood sugar values and the development of severe insulin shock unless he regularly received large amounts of carbohydrates. These investigators also assayed the insulin content of the tumor metastases in the liver, and found them to contain at least 40 units of insulin to each hundred grams of metastatic tumor, whereas portions of noncarcinomatous liver tissue were found to contain little or no insulin. In addition to this, the microscopic appearance of the tumor cells resembled the cells of the islands of Langerhans. The study of this case, clinically, pathologically and biochemically, was extremely complete and thorough, and can well serve as a