CHEMISTRY AND FOOD 253 



chamber. For explanation of the various parts refer- 

 ence must be made to fuller descriptions of the appara- 

 tus, e. g. y Bulletin 175 of the Office of Experiment Sta- 

 tions, United States Department of Agriculture, and 

 Publication 123 of the Carnegie Institution of Wash- 

 ington. 



When the experiments made by means of this original 

 respiration calorimeter had given sufficient knowledge 

 of the relative expenditures of energy at different times 

 of the day and night and under different conditions of 

 work and rest, it became possible to study particular 

 problems by means of apparatus of smaller size and of 

 particular design according to the nature of the problem 

 to be investigated. Examples of such apparatus are 

 the chair calorimeter and bed calorimeter (Figures 4 

 and 5) which are but two of the many improved calori- 

 meters devised by Dr. F. G. Benedict, the Director of 

 the Nutrition Laboratory of the Carnegie Institution 

 of Washington and the leading experimenter in this 

 field. Another important contribution made by Doctor 

 Benedict to the methods of research upon energy re- 

 quirements is the perfection of respiration apparatus 

 by means of which the amount of oxidation taking 

 place and of energy being used in the human body can 

 be accurately determined by means of measurements of 

 the oxygen consumed and the respiratory products 

 given off, which measurements are now accomplished 

 without necessitating the confinement of the man in the 

 respiration calorimeter. 



So fruitful did this line of study prove that notwith- 

 standing the considerable expense involved in making 



