1. The deposition of casein on a platinum anode which takes place on the passage of a direct current through solutions of alkali caseinates was quantitatively studied, and it was found that: (a) the amount of casein which is deposited is directly proportional to the current, i.e. it obeys Faraday's law; (b) the amount of casein deposited is inversely proportional (within the limits studied) to the amount of alkali which is combined with the casein.
2. A method of determining the transport numbers of proteins insoluble at their isoelectric point has been developed.
3. A titration method for determining the amount of alkali in a casein solution is given.
4. Data from the results of transference experiments on sodium caseinate, potassium caseinate, cesium caseinate, and rubidium caseinate solutions are given. It is shown that the data are best explained on the assumption that in these solutions the carriers of the current are alkali metal cations and casein anions.
5. On the basis of our transference results an explanation is given of the results which were obtained by Robertson and by Haas in their migration experiments.
