The cereal grains contain every inorganic element found in the animal body, and every one which is a necessary component of the diet, but in too small amounts in respect to three to enable the animals to grow. That insufficient mineral matter in a diet may produce grave pathological conditions reveals this moiety in a new and important light. The animal is sensitive either to the actual amounts of certain of the mineral elements in the food mixtures, or to the relationships among them. Sidney Ringer was led in 1891 to his description of Ringer's solution, as the result of the observation that muscle behaves more nearly normally in solutions containing certain salts in definite proportions. Ringer's solution contains for each one hundred molecules of sodium chlorid two molecules of calcium chlorid and between one and two molecules of potassium chlorid, together with a trace of a magnesium salt. Loeb, Howell and others have described many experiments showing the profound effects upon the subsequent development of the eggs, of varying in certain ways the composition of the salt solutions in which unfertilized eggs of certain marine animals were kept (9). In this way the earliest stages of development which are ordinarily observed only in the fertilized egg could be caused to take place in eggs into which no sperm had entered. In the nutrition of the higher animals it had never been made clear how dependent the organism is on the rate at which the blood stream receives mineral nutrients. The fact that the cereal grains are too low in three inorganic elements to admit of growth made it surprisingly clear that food packages just as they come from the hand of Nature are not necessarily so constituted as to promote health.