The Mechanism of Transport of Inorganic Anions across the Intestinal Wall of the Rat

　1）In the isolated small intestine of the rat the efflux of inorganic phosphate and iodide ion from the serosal to the mucosal side decreased when modified Ringer was applied to the mucosal side and the potential difference across the intestinal wall attained a new value, the mucosal side becoming positive．This decrease could not be influenced even when the P. D. was restored to the normal value by externally applied current．But it could be partially recovered by raising the hydrogen ion concentration on both sides．

　2）When similar P. D. was developed by externally applied current with normal Ringer on both sides, the efflux of phosphate and iodide changed in accordance with the notion of simple free diffusion．

　3）Using neutral collodion membrane of porous character as a model, the viscosity of the solution was shown not to play a dominant role in determining the rate of transport of phosphate and iodide．