There is a rough relationship between the type of pancreas and the nature of the lesions. The organ may be divided for this purpose into the compact organ firmly held in place by attachments to the lesser omentum, spleen and duodenum, and the velamentous organ which spreads a considerable distance along the duodenum and sends out digitations into the mesentery and thin processes toward the spleen. The first type is seen in primates and carnivores and birds, while the second is characteristic of rodents, ungulates and marsupials. The compact variety showed all but one of the chronic cases while the loose organ was affected by the acute pancreatitis in twelve of thirteen cases. The microanatomy of the cases may throw a little light upon our subject. I was able to see the duct in one case of acute pancreatitis (bear). It showed a simple catarrhal inflammation with a very moderate circumferential round cell increase. The destruction of glandular areas by edema, hemorrhage and necrosis offers nothing of importance except in a few birds. In these the necrosis is more definite about cross sections of ducts, and the islands of Langerhans are frequently spared until necrosis is locally complete. In a case of chronic pancreatitis in a bird, a cross section of pancreatic duct was found in the intestinal wall; a chronic catarrhal and infiltrative enteritis existed in this specimen. A very definite mantle of round cells was found about the duct while the mucosa showed no change, although the lumen seemed large. Interlobular fibrosis was the rule, only one case of intra-acinar pancreatitis being encountered; this specimen, a bird, showed great distortion of the acini and of the islets.