Until quite recently the principles of diet (even if not often carried out in practice) have been established on lines laid down by Carl Voit, of Munich; this eminent physiologist, after studying the dietary habits of various classes of workers, claimed that the adult man of 150 pounds, doing moderate muscular work, requires daily 118 grams of protein or albuminous food, 56 grams of fat, and 500 grams of carbo-hydrate, with a total fuel value of 3000 large calories, in order to maintain the body in equilibrium. But the remarkable and scientific experiments of Chittenden have demonstrated beyond question that perfect bodily and nitrogenous equilibrium can be maintained with one-third of the amount of protein called for by the Voit standard, and with a total value in the diet of only about 1600 calories, or about one-half of that indicated as necessary by Voit. These experiments were based on a group of five men of varying ages, professors and instructors at Yale, thirteen volunteers from the Hospital Corps of the United States Army, and eight students in Yale, all thoroughly trained athletes, twenty-six in all. It would be quite beyond the scope of this lecture to enter at all into the intricate questions connected with the metabolism of nitrogenous and other foods, but Chittenden has well put the reasons “why prominence is given to the establishment of nitrogenous equilibrium and why the proteid intake assumes a greater importance than the daily amount of fat and carbo-hydrate consumed. Fats and carbohydrates when oxidized in the body are ultimately burned to simple gaseous products, viz., carbonic acid and water. Hence these waste products are easily and quickly eliminated and cannot exercise much deleterious influence, even when formed in excess.... With protein foods, on the other hand, the story is quite different. These substances when oxidized yield a row of crystalline, nitrogenous products which ultimately pass out of the body through the kidneys. Prior to their excretion, however, these products—frequently spoken of as toxins—float through the body and may exercise more or less of a deleterious influence upon the system, or, being temporarily deposited, may exert some specific or local influence that calls for speedy removal. Hence the importance of restricting the production of these bodies to the minimal amount, owing to their possible physiological effect and the part they are liable to play in the causation of many diseased conditions.”