252 SCIENCE REMAKING THE WORLD 



food needs has been gained from the simplest food 

 study of the elementary school or from the most ad- 

 vanced university course in the chemistry of food and 

 nutrition. 



FUEL OR ENERGY VALUES OF FOOD THE TOTAL 

 FOOD REQUIREMENT. The exact quantitative deter- 

 mination of human food requirements is chiefly the out- 

 growth of the nutrition investigations begun by means 

 of a small appropriation made by Congress to the 

 United States Department of Agriculture and expended 

 under the direction of Dr. W. O. Atwater, late Professor 

 of Chemistry in Wesleyan University. Professors At- 

 water, Rosa, and Benedict constructed in the basement 

 of the chemical laboratory of Wesleyan University at 

 Middletown, Connecticut, the first practically success- 

 ful apparatus for the measurement of the energy ex- 

 changes in, and the energy needs of, the human body, i 



The outstanding achievement of Professor Atwater's 

 work in this field was the development of a respiration 

 calorimeter suited to direct experiments with men at 

 rest and at work, and the perfection of this apparatus 

 until it became truly an instrument of precision. This 

 respiration calorimeter provided a copper room seven 

 feet long, four feet wide, six and one-half feet high in 

 which a man may live as many days as the particular 

 experiment may require, and fitted with means for 

 measuring accurately the amounts of energy used by 

 the man under various conditions of activity and occu- 

 pation. Figure I shows a general view of this appara- 

 tus as it was developed and used in the Atwater labora- 

 tory; Figures 2 and 3 show inside views of the living 



