The recent literature on acidified milk in infant feeding has been repeatedly 1 reviewed in this journal, and therefore need not be summarized again.The modification of cow's milk by the addition of acid is based on the high content of buffer substances in cow's milk, the resistance of which must be broken down before gastric digestion can proceed normally. The buffering property of milk was recognized first by Leo 2 in 1888, and was soon thereafter studied by Escherich3 (1889), by Heubner 4 (1891), and by M\l=u"\ller 5 ( 1892). M\l=u"\llerfound that it was two to three times as great in cow's milk as in human milk These workers employed the method of titrating with hydrochloric acid, using congo red (Ph range from 3 to 5) as an indicator. It was not until 1914 that the buffer curve of milk was charted according to hydrogen ion concentration. This was done by Aron 6 for both human and cow's milk, and the striking difference between the two was clearly defined. In the same year, Clark 7 noted the high buffer concentration of cow's milk, and called attention to the absurdity of lime water additions, which still further increased the difficulties of gastric digestion.