121 
SUMMARY AND RESULTS OF THE EXPERIMENTS. 
SCOPE OF THE INVESTIGATIONS. 
Number of experiments and experimental days. — Between February. 
1896, and April. L900, inclusive, 34 experiments, covering a period of 
114 days, were made with the respiration calorimeter. 
The tirst four of these, covering a period of 21 days, were desig- 
nated as experiments Nos. 1-1. and the results were published in a 
previous bulletin. 1 ' Nine of the 12 days covered by experiment No. 1, 
however, really comprised three separate experiments, distinguished 
from one another by difference in occupation of the subject: these, for 
convenience, may be designated as la. lb. and 1c. In all these 
experiments (Xos. l-4c) the income and outgo of nitrogen and carbon 
and the income of energy were determined, but the heat given off 
from the body was not measured. Since they show only the bal- 
ance of income and outgo of matter, including the material excreted 
in the breath, they are termed ;% respiration" experiments. 
The results of six other experiments. Xos. 5-10. covering a period 
of 24 days, have also been published. b In these, and all later experi- 
ments, the balance of income and outgo of nitrogen, carbon, hydrogen, 
and energy was determined, and they are. therefore, termed "respira- 
tion calorimeter" or •• metabolism" experiments. 
Of the remaining 24 experiments. 13, covering a period of 41 days, 
are reported in detail in the present bulletin: the results of the other 
11 experiments, covering a period of 2^ days, and belonging to another 
investigation, are reported elsewhere. 
Accordingly, the total number of respiration calorimeter experi- 
ments thus far decribed. including those in the present report, is 30, 
covering 93 days. Besides these. 14 experiments, covering 41 days, 
made in the winter and spring of 1900-1901, are now completed and 
nearly ready for publication, thus making 44 experiments. Xos. 4-4S, 
covering 134 days, in which the balance of nitrogen, carbon, hydro- 
gen, and energy has been directly measured. Adding the respiration 
experiments, included in Xos. l-4c and covering 21 days, we have 48 
experiments, covering 155 days, in which the balance of nitrogen and 
carbon was determined. 
Each metabolism experiment, or series of experiments, was imme- 
diately preceded by a digestion experiment of several days' duration, 
in which the subject had the same diet as in the metabolism experi- 
ment, the purpose being to bring the body into approximate nitrogen 
*U. S. Dept. Agr., Office of Experiment Stations Bui. 44. 
! U. S. Dept. Aer.. Office of Experiment Stations Bills. 63 and 69. 
e Memoirs of the National Academy of Sciences, Vol. VIII. Sixth Memoir, 1902. 
