It is perhaps trite but a truism to say that advances in physiology depend to a considerable extent upon improvements in technical methods. Much of the data of classical physiology has of necessity been derived from acute mammalian experiments. The value of experimental data obtained from investigation of intact, unanesthetized animal preparations is self evident. In this respect study of external function of the pancreas is greatly favored by the use of total permanent external pancreatic fistula animals, in which unphysiologic factors are largely eliminated. The technic of fistula preparation described here (retrograde external pancreatic fistula) affords simplicity of technic with low immediate operative mortality and a high percentage of successful results. There is a minimum chance for pancreatic infection, and no interference with nerve supply and only a negligible interference with blood supply. No apparent atrophy of the pancreas was observed grossly or microscopically after four months.