THE EXACT mechanism in the production of acute hemorrhagic pancreatitis is unknown. Although acute pancreatitis was first produced experimentally in 1855,1 we are today still uncertain of the relative importance of the various factors involved in the pathogenesis of inflammatory and necrotizing lesions of the pancreas. That this subject is of direct practical importance to the surgeon will be illustrated in cases to be described. The problem as encountered at the Alexander Blain Hospital is such that during the past five years an average of only 1 patient a year has been treated, with a mortality rate of 40 per cent. The 2 deaths occurred in patients with hemorrhagic pancreatitis. One death occurred five years after cholecystectomy and choledochotomy for stones in the common duct. At autopsy the main pancreatic duct was found to be occluded by a stone impacted in the ampulla of Vater. All the 3