The study of comparative pathology of pancreatitis does not settle its etiology, but some very suggestive facts may be learned. The association of hepatic and biliary disease and of enteritis in the causation of pancreatitis seems amply confirmed, and the latter factor is in our series numerically the greater. It is suggestively shown that inflammations of the pancreas occur more frequently in the zoological class in which the ducts of the organ and of the liver empty into the duodenum together or in close association. Moreover, infections of the liver and adnexa are very important in the mammals, more so than birds in which enteritis, notably chronic in type, usually accompanied the involvement of the pancreas. This is consistent with the incidence of bile tract disease as already discussed under that subject, and it is interesting to note that the mammals showing the greatest number of cases of choledochitis and cholangitis also show the high case incidence of pancreatitis. The birds that have bile tract disease have little pancreatic disease. These facts when considered in connection with the free biliary supply of the avian duodenum, the disassociation of the ducts of the two glands and the close apposition of the pancreas to the duodenal wall, suggest strongly that direct infection of the pancreas can occur from the intestinal wall along the walls of the ducts perhaps via the lymphatics. This is supported by the observation of at least one case in which there was a definite inflammation under the adventitia of the pancreatic duct, its mucosa being normal. The study also suggests that acute pancreatitis is more often associated with acute lesions in the intestines and with hepatic or gall-bladder disease, and that chronic pancreatitis seems more often the result of chronic or repeated intestinal inflammation. Peripheral inflammation such as occurs in gastric or duodenal ulcers, has not been encountered in a distinct character so that its value cannot be estimated. [Illustration: FIG. 20.—ADENOMA OF PANCREATIC DUCTS. CORSAC FOX (CANIS CORSAC). ] Cystic change in the pancreas has been observed a few times, but never a large visceral collection or the so-called extra-pancreatic cysts of the omentum. One acinus cyst was seen in a drake, one congenital cyst in a lark, and multiple ductal cysts were seen in a baboon and a duck. The parenchyma in all cases seemed entirely capable of functionating. TUMORS.