=Treatment.= Cod-liver oil and sunshine, together with proper food, are the essentials in treating rickets. When cod-liver oil is given to a baby whose diet is faulty, it exerts a marked tendency toward enabling the bones to develop satisfactorily even when the mineral content of the food is unfavorable. The use of sunshine, either by moving the baby from a dark to a light house, or by exposing his body to the direct rays of the sun is found to be of pronounced therapeutic value. These factors, in addition to general good care constitute the treatment, but it is a long slow process, taking from three to fifteen months, and it is doubtful if the damage which the disease works can ever be entirely repaired. Rickets is more common during the cold months of the year, winter and spring, than during the milder summer and autumn seasons. A possible explanation for this lies in the higher value of the cows’ food during the warm months when green things form the diets of animals. Since it is now recognized that milk is not a constant product, but that its properties vary with the food of the animals that produce it, cows’ milk would be favorably influenced by their being put to pasture. Similar evidence of such an influence is seen in the fact that although rickets is not seen among breast-fed babies whose mothers are on satisfactory diets, it may and does occur in breast-fed babies who are nourished by mothers who are, themselves, on dietaries which are poor in milk and fresh fruit and vegetables. Drs. Hess and Unger made a study of the occurrence of rickets among colored babies in a section of New York City and the value of cod-liver oil as a preventive of this disease. In commenting upon their findings, they state, “This tendency is so marked that it may be safely stated that over ninety per cent. of the colored babies have rickets, and that even a majority of those that are breast-fed show some signs of this disorder.” They ascertained that the average diet of the mothers of these rickety babies was largely made up of carbohydrates and proteins, being poor in fats, although the diets yielded a daily quota of calories which represented almost the requisite amount for their individual weights. But they took little fresh milk or fresh fruit or vegetables, using canned and dried products freely. It is important to note here that it is a diet of heated milk, rich in carbohydrates but poor in fats, that produces rickets in a bottle-fed baby—almost the same type of diet which in a nursing mother results in rickets in a breast-fed baby.