Summing up the conclusions reached by him after arduous years of experiment and study, Professor Chittenden declares that 60 grams of proteid (about the quantity which a single small chop would supply) are all that are required by the average man of 150 pounds body weight. This is one-half the Voit standard, and far below the common practices of the majority of mankind in Europe and America. “But there should be no practical use of the terms ‘standard diets’ and ‘normal diets’ by people in general,” says Professor Chittenden. “What is needed to-day is not so much an acceptance of the view that man needs so many grams of proteid per kilogram of body weight, as a full appreciation of the general principle that the requirements of the body for proteid food are far less than the common customs of mankind, and that there are both economy and gain in following this principle in practice.” HOW TO INCREASE ENDURANCE The most broadly interesting of these Yale food experiments are those having to do with the question of endurance. The vast majority of people are not ambitious to excel as athletes; they find better and more enjoyable forms of work in life than putting up big dumb-bells, or breaking records on the athletic field. Of course, everybody wants to be strong, and to have well-trained and active muscles; but on the whole, what the majority of people need is physical and mental stick-to-itiveness—the ability to work without deterioration, without running down like worn-out machinery. Professional men, day laborers, students and athletes, all need this invaluable quality of endurance—this quality that is the true capital in the bank of life to be at their command day in and day out, with a reserve ready to be drawn upon whenever an emergency arises. And it is precisely here that the new art of health bestows its benefits upon those who follow it. It was to ascertain the relation between diet and endurance in the light of the new knowledge shed upon the subject by Professor Chittenden’s experiments, that Professor Irving Fisher inaugurated his own experiments at Yale University. He conducted two series of tests, as follows: First, to ascertain the effect of thorough mastication on endurance, following the rules laid down by Horace Fletcher, with the help of nine healthy students. Second, to ascertain the influence of flesh eating on endurance as compared with the effect of abstinence from flesh, with a group of forty-nine persons, splitting the group as follows,—first, athletes accustomed to a flesh, or high proteid dietary; second, athletes accustomed to a low proteid, or non-flesh dietary; third, sedentary persons accustomed to a low proteid, or non-flesh dietary. [Illustration: PROF. IRVING FISHER, PH.D., Professor of Economics at Yale University. His investigations have had to do largely with the cost of necessary food.]