Some time ago the writer began a series of investigations on the conditions for the activity of proteoclastic enzymes of wheat and flour.' The extent of protein hydrolysis in the auto-digestion experiments was determined by means of the formol titration method of Sorensen. After this had been used for some time an attempt was made to substitute electrometric titration for it. The results obtained were so encouraging that further work was deemed advisable. Before much headway could be made in

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... study of protein hydrolysis of ~IOUK, however, it was necessary to know the behavior of the different degradation products of protein hydrolysis upon the hydrogen electrode. A few of the simpler amino acids were lirst investigated from this point of view, namely glycocoll, a monoamino monocarboxylic acid ; phenylalanin, a monoamino monocarboxylic acid containing the benzene ring; lysin, a diamino monocarboxylic acid ; glutamic acid, a monoamino dicarboxylic acid ; and tyrosin, a monoamino monocarboxylic acid containing an hydroxyl group in the k m " e ring. Several investigators have determined the hydrogen ion concentration I This work on flour was done under the direction of Prof. C. 0. Swanson.