A rat (1) whose diet consisted of rolled oats supplemented with fat-soluble A in the form of butter fat, induced growth in her litter of four at a rate somewhat greater than she could have done had she eaten rolled oats alone. On this food mixture she was able to keep them alive for a somewhat longer period. The first one died on the 57th day and the remaining ones followed in rapid succession. This mother lost considerable weight up to the time when the young began to eat of the oat and butter fat diet. Young rats, after removal from the mother, cannot grow on this diet.

Chart 9. - The curves at the top of this chart show the rate of growth of litters of four young each, when they were nursed by mothers taking the diets listed. No. 211 is an excellent diet containing a liberal amount of dried milk. On this the mother is able to induce rapid growth in her young.

Lots 980, 1019 and 1020 were given rolled oats and a protein supplement, either gelatin or casein, together with a mineral salt addition. Lots 984, 949, and 948 did not receive the supplementary salt additions. The inferiority of their young as contrasted with the first named group is very marked. Lot 984 was given a supplementary supply of fat-soluble A over that which was contained in the seeds. This prevented the early failure of the young as happened in Lots 948 and 949 which were not given an additional supply of this substance over what was furnished by rolled oats. These curves show clearly that the quality of the mother's milk is profoundly influenced by the character of her diet. If she is selectively fasted for mineral elements, fat-soluble A, water-soluble B, or water-soluble C, or if the proteins of her diet are not of good quality her milk is deficient in the substances which are wanting, relatively, in her diet. It is of the utmost importance that the diet of the nursing mother should be of very excellent quality with respect to all its parts.

The curves at the bottom of the chart are also of great interest. Note that those mothers which were fed rolled oats supplemented with a protein and a salt mixture were able to sustain their body weight much better than could those which were fed oats and a protein or oats, protein and butter fat. The draft upon the vitality of the mother while nursing young will be greatly relieved by making her diet highly satisfactory. Note that Lots 948, 949 and 984 lost weight much more rapidly than did those mothers whose diets were better constituted for the promotion of growth in their young.

A mother rat was fed a diet of rolled oats to which was added an inorganic salt mixture so made up as to correct the mineral deficiencies of the oat kernel. Her diet still lacked fat-soluble A and the anti-rachitic substance and its proteins were below the optimum both in quality and quantity. With this food her milk was distinctly better in quality than she could have secreted had she been restricted to either oats alone or to oats and butter fat or to oats supplemented with purified protein. From these results it is apparent that for milk production the first limiting factor in the oat kernel is the same as for growth in the young. That limiting factor is the inorganic content of the food supply.