In the course of these pages, I have traced the beginnings of the development of exact knowledge of the processes of nutrition, and have shown how the science expanded through the intricate reasoning and refined experimental studies of an era, the great popularity of which has not yet begun to wane. The fundamental principles have been illustrated in all cases through the results of animal experimentation. After these fundamentals had been established there followed a study of human experience with diet, throughout history man's most pressing problem, and finally an application of the discoveries of this branch of physiological science to an interpretation of certain of the present day problems of health and their solution. It has been a joy to do this. The concentrated efforts of the author during a period of fourteen years have been devoted to observing the effects of diets of different types on experimental animals. During this time a continuous search has been carried on for information of any and every kind which would aid in correlating the results of the laboratory with those of practical experience. Year by year this has increased his conviction that the scientific discoveries in the field of nutrition are destined to be recognized as the most fundamental of the agencies that contribute to the health, happiness and achievement of man.

Some time must elapse before a full appreciation of the importance of approximating the optimum in the character of the food supply can be expected, but when appreciated at its full value, our knowledge in the field of the science of nutrition will be regarded as our most precious possession.

Fig. 20. - Illustrates the extent to which the teeth have degenerated among Americans in recent times. The trouble lies in great measure in faulty nutrition during prenatal life, infancy and childhood. A satisfactory diet is essential for the development of a sound set of teeth. If the jaws and teeth are poorly developed they must throughout life be vulnerable to bacterial agencies. - Courtesy of The Forsyth Dental Clinic.