Experiments with animals have shown that diets deficient in vitamin C or D or unbalanced in their calcium and phosphorus content often lead to structural defects (hypoplasia) of bones and teeth.1 Histologic examination of carious teeth of children2 revealed a high incidence of such defects, and it was concluded that hypoplasia predisposes to dental caries. Mellanby3 stated that diet, by improving structure, might lead to an arrest of caries in the human being, and observations on children and adults showed that it was often possible to arrest caries with carefully controlled diets. Other investigators4 found that a well balanced diet seemed to decrease the incidence of caries both in animals and in human beings. Hanke and Bunting,5 in recently reported studies, have considered this subject in detail.
In view of these observations, it seemed important to determine which constituents of the diet, if any, played