1. A group of rats has been fed on a poor human dietary supplemented with milk and green food. A further group has been given the same dietary supplemented with Ca and P as salts, equivalent in amount to that present in the milk and green food. The experiment has been continued over three generations.
2. The diet supplemented with Ca and P salts has been found to be as effective as that containing milk and green food in promoting reproduction, calcification and tooth formation; it has induced growth as effectively in the first generation of rats but is unable to maintain this growth rate as effectively over several generations. It is obvious that Ca and P are of the chief deficiencies in the poor diet. The addition of these elements greatly increases the nutritive value of this diet, but they are inferior in this respect to milk and green food supplements.
3. Under conditions of Ca and P lack, tooth formation is much less adversely affected than is skeletal ossification.