A quantitative method for the investigation of electrostenolysis has been developed. Electrostenolysis is redefined in the light of the discovery that organic molecules are subject to it. The experimental requirements for a quantitative study are enumerated, and the apparatus and procedure described. It is found that with ferrous and ferric ions and a cellulose acetate membrane, the potential drop across the membrane must be above about 2150 v./cm. in order to effect any oxidation and reduction. With the present apparatus and conditions the ratio of equivalents oxidized or reduced to faradays passing the membrane is low,— of the order of one to several thousand.