LETTER OF TRANSMITTAL. 
U. S. Department of Agriculture. 
Office of Experiment Stations, 
Washington, D. C December IS, 1901. 
Sir: I have the honor to transmit herewith a general report of 13 
experiments on the metabolism of matter and energy in the human 
bodv. by W. O. Atwater. special agent in charge of nutrition investi- 
gations, and F. G. Benedict, expert in these investigations, with the 
cooperation of A. P. Bryant. A. W. Smith, and J. F. Snell. Valuable 
aid was also rendered by Messrs. P. B. Hawk. H. M. Burr. E. Oster- 
berg. and others. In addition to the details of these 13 experiments 
on the general subject of the metabolism of matter and energy a con- 
siderable number of general deductions are drawn from the experi- 
ments as a whole. 
These experiments form part of a series which is in progress atMid- 
dletown. Conn., in cooperation with the Storrs Agricultural Experi- 
ment Station and Wesleyan University. They were made with the 
Atwater-Rosa respiration calorimeter. The apparatus and the earlier 
experiments have been described in previous bulletins of this Office 
(Nos. 14. 63, and 69). Such experiments as those reported have for 
their ultimate object the study of the fundamental laws of nutrition. 
The results obtained are of such a nature as to warrant the conclusion 
that the respiration calorimeter is a satisfactory instrument of preci- 
sion. The experiments here described, like those previously reported, 
yield important data regarding the transformation and the conserva- 
tion of energy in the body, the demands of the body for nutriment, 
the effects of muscular work upon that demand, and the nutritive values 
of different nutrients and different foods. 
The report is submitted with the recommendation that it be published 
as Bulletin No. 109 of this Office. 
Respectfully. A. C. True. 
Director, 
Hon. James Wilson. 
v tary ofAgricultm 
