The progress of caries is reported among 169 children living in an orphanage. They were under observation for periods varying from 1 to 4½ years. Improvements made in the diet of the children brought about marked improvement in the height and weight of most of them and some increase in the alkaline reserve of the saliva. This latter increase was not at all proportional, however, to the increased alkaline value of the diet. Bacteriological tests on the saliva of a selected group of these children gave results that checked with the dental findings in 84 per cent of the cases studied. The small percentage of cases in which the dental findings could not be satisfactorily explained on the basis of the quantitative bacteriological findings was slightly lower than observed in our studies of children in University Hospital. No correlation could be found between the dental findings and any of the following factors: Height or weight status of the children. Sex. The carbon dioxide carrying power of the saliva. The intake of calcium or phosphorus or vitamin D. Probable access to other food. The order in which hard fibrous fruit was eaten. The low incidence of caries among the children could not be explained on the basis of the superior nutritional value of their diet. Almost half of the caloric intake was from starchy food. There were two other dietary factors that may explain why the incidence of caries was so low in this institution. One was the low intake of artificially sweetened food. The other was the great regularity of the meals and the uniformity in quality of the food served. If these were the controlling factorswe offer no explanation of how they operated. We merely submit our evidence in support of them.