This test of work was accomplished on food of the nitrogen value of less than 7 grams daily, whereas the text-books declare that from 16 to 25 grams of nitrogen are necessary to human existence. The heat value of the food consumed during the test, and which was like in amount to what had been habitually taken by the author for about five years previously (less than 1600 large Calories), was only _half the amount_ set down by the majority of the presently-accepted authorities as necessary to run the body of a man of the author's weight and activity. The heat-economy-showing was verified a week or two later in a 32-hour calorimeter measurement in the apparatus of Professors Atwater and Benedict at Middletown, Conn. Evidence of even more significant value has accumulated outside the field of the author's own experiments and tests. After more than a year of careful trial among some thousands of patients and among some hundreds of earnest employees, Dr. James H. Kellogg, of the great Battle Creek Sanitarium, has adopted the suggestions contained in this book as the first requirement of the treatment at the Sanitarium. In like manner, Dr. Edward Hooker Dewey, the sturdy advocate of dietary-economy for the past thirty years, author of the "No-Breakfast" regimen, and various books upon the subject of auto-nutrition and dietary-rest, bent his attention upon the effect of thorough buccal digestion prescribed after a period of rest from outside feeding, and here follows his appreciation as extracted from personal letters. Before quoting from the high appreciation of Dr. Dewey and Dr. Kellogg it may be well to state that the author stands simply for a test-subject-factor in a commonweal natural inquiry and no praise of the subject attaches to the person of the author. Whatever the author is, in the enjoyment of health and strength, is the result of natural causes which have developed during his study of the natural requirements in our nutrition. Please forget the personal element and consider that what is the author's gain in efficiency as related, is the possible possession of the reader as well, and whatever work or test the author performs is done as much for the reader as for the author himself.