INTRODUCTION
The investigations of Osborne and Mendel1 have shown the important part taken by the whey salts in the growth and development of the young rat, and Holt, Levene and others2 have shown that a proper adjustment of the relation between the amount of whey and some of the other constituents present in infant-foods is quite necessary in order to prevent disturbances in the normal metabolism and physical condition of artificially fed infants. It has, therefore, become necessary, in our studies of infant-feeding, for us to know more about the significance of whey, especially in connection with the treatment of certain types of infectious diarrhea, fat intolerance and regulation of feeding, and the investigations reported here are some of the results obtained by us in this connection.The baby used for this investigation was of a rather happy disposition and had been used by us, some months previous