(1) The monomolecular or multimolecular films of stearic acid or of palmitic acid were formed at the upper surface of sodium sulphite solution, and the velocity of the oxidation of sodium sulphite solution was studied, the main body of the solution being well agitated with a stirrer of special construction. It was confirmed that the velocity of the oxidation of sodium sulphite solution by oxygen, observed in the presence of the molecules of these fatty acids, and that observed in the absence of the molecules of the fatty acids, are almost identical under the conditions above described. (2) A short discussion on the result of the present experiments was made. The assumption, that a stationary liquid layer is present at the interface between gas and liquid, seems to be unfavourable to the interpretation of the phenomenon observed by the present writers. It was stated that the assumption, that the molecules of fatty acid at the upper surface of the liquid will also be agitated by the stirring of the main body of the liquid and covered with the solution, has great probability for the interpretation of the result of the present experiments. (3) The mechanism of solution of gas into liquid was shortly discussed. A part of the opinion of one of the present writers (Miyomoto) on the rate of solution of gases into liquids was described.