Only forty minutes from New Haven by rail,--a distance not greater, as measured by time separation, than from one side of London to the other,--at Middletown, Conn., stood also the recently completed calorimeter of Professors Atwater and Benedict ready for making a calorimetric trial-balance measurement of metabolism attained and chemically estimated in the tests at New Haven. After the Yale demonstration, of which Professor Chittenden’s article, previously mentioned, treats, the author responded to an invitation from Professor Atwater and submitted himself to a 32-hour confinement in the calorimeter for confirmation of the results obtained at New Haven. This experience in the calorimeter at Middletown was very significant and instructive. The author was the first test-subject used in the newly completed calorimeter. The oxygen-measuring attachment of Dr. Benedict that completed the apparatus and gave a complete trial balance of the metabolism of the subject under examination was as yet untried, but it proved its integrity within the fraction of one per cent and registered as accurately as necessary for all practical purposes. So much for the machine; but it measured a result which is of the greatest importance to the human race. The author had just demonstrated the possibility of running the human machine on half the heat, on one-third of the fuel, and with only one-tenth of the waste, as represented by the waste, or ashes of digestion. Not only was this done while in pursuit of the ordinary activity of present-day life, but under stress of 'Varsity-Crew exercise, as reported by Professor Chittenden and Dr. Anderson. Had this demonstration been made relative to steam engines or electrical motors, the information would have been revolutionary in establishing new values for things industrial and commercial. Its significance relative to human profitable possibilities is even more important than if related to steam or electrical power. The possibility of economy in the human machine gives also a hope of immunity from the common diseases which now afflict mankind. The trial of the calorimeter as a measuring machine and the trial balance of the economic metabolism which the author had attained by five years of careful attention to the natural requirements of nutrition were epoch-making events coincidently related, and for them the author here makes this distinguished claim--not on account of any accomplishment of himself, but as a promise of great possibilities for human betterment.