16 STORRS AGRICULTURAL KXPERIMENT STATION. 
materials belonging to the experiments. In like manner there 
is need of the greatest possible care and accuracy in the deter- 
mination of the gaseous excretory products. Nor can any of 
the organic matters given off in perspiration and exhalation be 
left out of account if the fullest accuracy is to be attained. 
3. It is to be hoped that future experience may lead to such 
improvements as shall insure the accurate measurement of all 
the chemical elements involved in the income and outgo. It is 
evident that there are no insurmountable obstacles in the way 
of reasonably accurate estimation of the income and outgo of 
nitrogen and carbon. As regards the hydrogen the difficulties 
of determination have thus far been more serious, but they do 
not appear to be by any means insurmountable. ‘The quan- 
tities of sulphur and phosphorus are so small that extreme 
accuracy is needed for their estimation in order to insure satis- 
factory comparison of income and outgo. ‘The experience in 
this laboratory leads us, however, to hope that by refinement 
of methods and care in manipulation reasonably reliable results 
may be obtained. 
4. The prospects for obtaining a satisfactory balance of 
income and outgo of energy are on the whole decidedly en- 
couraging. The determination of heats of combustion by the 
bomb calorimeter are eminently satisfactory and there seems 
to be good ground to hope that ultimately the measurements 
of heat given off from the body may also prove feasible within 
the limits needed for such purposes. Satisfactory results have 
already been reported by other experimenters with small 
animals, and indeed with men during experiments of short 
duration. 
5. The results of these experiments and of similar investi- 
gations elsewhere bring out very clearly the differences in the 
amounts of nutrients and energy required by the organisms of 
different persons under different conditions. A large amount 
of work will be needed, however, to bring the experimental 
data necessary for accurate generalizations. ‘The importance 
of the subject is such as to call for the most extensive and 
painstaking research. We may confidently expect that with 
the growth of inquiry, which has of late become so rapid in 
Europe, and may be anticipated in the United States, the 
needed information will gradually accumulate. 
