


INVESTIGATIONS ON METABOLISM. 87 
regarding the balance of income and outgo of energy are to 
be held until some changes, which experience has indicated 
to be desirable in the apparatus and methods, can be made, 
and the results already obtained can be verified and new ones 
added. 
In the devising and elaborating of the apparatus, as well as 
in the actual carrying out of the experimental work, Prof. 
H. B. Rosa of Wesleyan University has had an active share. 
Upon him has devolved especially the devising and care of that 
part of the apparatus and inquiry which has to do with its 
physical side, including the measurement of the heat radiated 
from the body. ‘The chemical side of the inquiry, and with it 
the determinations of the potential energy of the products of 
income and outgo have been superintended by Prof. Atwater. 
Besides the names of the authors of the present report those 
of the collaborators should be mentioned. Mr. A. W. Smith 
had much to do with the development of the apparatus, es- 
pecially the physical side, and with the carrying out of the 
experiments. He was himself the subject of the last of the four 
experiments here described. Dr. O. F. Tower has done a large 
amount of the chemical work and has been otherwise asso- 
ciated with the experiments. He was the subject of the third 
experiment of the four recounted here. Mr. A. P. Bryant 
rendered valuable assistance in the chemical part of the inquiry. 
Mr. H. M. Burr had the charge of the preparation of the food 
for the experiments and has had a large share in the work of 
analysis. 
It is now expected that the part of the work which bears 
more directly upon the conservation of energy will be pub- 
lished hereafter under the joint authorship of Professors 
Atwater and Rosa. 
The following is an abbreviated description of the apparatus 
and methods used and of the results of four experiments upon 
the income and outgo of carbon and nitrogen. In each of the 
experiments the subject remained for several days inside the 
respiration chamber, the periods being from two and one- 
fourth to twelve days. 
A more detailed report of the experiments here described 
has been made to the Department of Agriculture for publica- 
tion in a Bulletin of the Office of Experiment Stations. The 
