Entirely the same method was used in this series. Serum chloride was measured by the silver-iodate method and serum sodium by the uranyl zinc acetate method. It was found that serum chloride decreased in experimental pancreatic necrosis. Progressive decrease was observed in the severe group. Following early immediate decrease after the onset of pancreatic necrosis and subsequent return to the preexperimental level, serum chloride decreased once again. The lowest value occurred on the 3rd day and then gradually returned to the normal level. It was observed that serum sodium decreased in experimental pancreatic necrosis. There was found no marked change in serum sodium in the severe group. No definite change occurred in the early stage of experimental disease in the mild group, but it decreased 12 and 24 hours later. The lowest value on the average occurred on the 2nd day of disease and then it gradually returned to the preexperimental value.