In an earlier chapter it has been shown how easily deviations from the optimal composition of the diet with respect to certain factors, leads to the development in the bones of histological changes easily demonstrable. These changes are prominent in rickets and kindred conditions. It should be fully appreciated by all, that the process of enamel development in the teeth, their eruption and nutrition is a part of the development of the osseous system, and is affected by the same factors that influence bone growth. If a tooth is poorly made, the best that can be done for its preservation is frequent repair. Teeth are developed and enameled before they are erupted, and these events take place during the last months before birth and following birth. During infancy the permanent teeth develop just under the milk teeth. The importance of providing at this epoch in the life of the child, an uninterrupted state of nutrition which is as nearly the optimal as possible, will serve as the most effective measure in providing in the child a dental equipment which will last well into old age and protect against the danger of invasion by microorganisms which now so frequently cause serious infections. Although it may sound prophetic at this time, when we have become so thoroughly schooled in referring almost exclusively the health problems of the human race to the field of bacteriology and parasitology, I cannot close this discussion without asserting that there is an even more fundamental, indispensable feature of health promotion than these. The basis for everything that is worth while in life lies in physical vigor, and as a means of securing for the young, the adult of the future, this priceless treasure, the importance of a properly adjusted dietary can scarcely be over-emphasized (17).

This chapter on the nursing mother strikes the keynote of this book, for it affords proof of the existence of and points the way to the remedy for one of the greatest sources of human inefficiency and suffering. Moreover, touching as it does the root of the evil effects of one of the most colossal errors of civilization, this chapter serves to illustrate most vividly the far-reaching importance of scientific nutrition in preventive medicine.

Fig. 18. - This illustration shows the great differences in the size, stage of development and vigor in young rats, which may result from faults in the character of the diets of the mothers which they are nursing. These three rats were the same age. The mother of the two little ones received a diet which was deficient in the quantity and quality of its proteins.