Many investigators in the science of nutrition have demonstrated that in certain animals the rate of growth and the size can be influenced through the choice of foods, irrespective of heredity and environment. With the rapid progress in the study of foods along this line, various experiments on the growth of children have been undertaken, and much has been said concerning the "normal" rates of growth.Several standards are now employed for these "normal" calculations, but a student of a critical mind must necessarily question the accuracy of the "normal," since many factors must be involved in drawing a conclusion. Generally and for the most part, the "normal" has been applied merely to the rate of growth in body weight compatible with a given height and age. For a number of years it has appeared to one of us (D. E. L.) that overemphasis has been placed on this phase of "normal" development, for there appear other factors of equal importance in making standards of child health, including resistance to infec¬ tions, overcoming development of organic diseases, endurance and mentality, the sum of all data indicating the desirability of any choice of foods. Many investigations have demonstrated interesting data on these phases of life, without special reference to standards of growth.It is gratifying to learn that investigators are gradually realizing that weight, height and age calculations may have serious limitations, and that they are coming more and more to employ other criteria for evaluating the "normal" development of children. In 1922,1 one of us (D. E. L.) published the results of some clinical experience with these ideas in mind, hoping to stimulate interest and questions, with the view to carrying out controlled experiments at some future time.During the last two years this plan, as far as it has gone, has met with success in the conducting of two experiments in child feeding. One includes a study in the nutrition of pregnancy, lactation and infancy, which will be published later ; the other deals with the nutrition of a group of children from 7 to 15 years of age, and forms the basis of this paper.