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. Further, the elimination of excessive amounts of these crystalline nitrogenous bodies through the kidneys places upon these organs an unnecessary burden which is liable to endanger their integrity and possibly result in serious injury, to say nothing of an early impairment of function. * * * * * The present experiments were undertaken to throw light upon this broad question of a possible physiological economy in nutrition, and with special reference to the minimal proteid requirement of the healthy man under ordinary conditions of life. The writer as a student of physiology has always maintained that man is disposed to eat far more than the needs of the body require, but his active interest in this problem was aroused especially by his observations of Mr. Fletcher and the marked physiological economy the latter was able to practice, not only without detriment, but apparently with great gain to the body as regards strength, vigor, and endurance, coupled with an apparent resistance to disease. While Mr. Fletcher and Dr. Van Someren would doubtless emphasize the importance of insalivation as a means of controlling the appetite and thereby regulating the consumption of food in harmony with the real needs of the body, it is of primary importance for the physiologist and for mankind to know definitely how far it is possible to reduce the intake of food with perfect safety and without loss of that strength, mental and physical, vigor, and endurance which are characteristic of good health. Further, it is equally plain that if there is possible gain to the body from a practice of physiological economy in diet, we should know how far this can be accomplished by simple restriction in the amount of food without complicating the problem by other factors.