TL STORRS AGRICULTURAL EXPERIMENT STATION. : 
unavoidable, since we have neither the means for measuring 
potential energy as such, nora unit for expressing the measure- 
ments if they were made. The use of heat of oxidation for 
the measure is especially appropriate here, since the energy 
is liberated mainly by oxidation and appears chiefly or entirely 
as heat. 
If the law of the conservation of energy obtains in the living 
organism, the net income and the net outgo of energy should be 
the same. In such physiological experimenting; however, it 
would be hardly fair to expect the figures for the two to agree 
for each day of a given experiment or for each experiment as a 
whole, even if the measurements with the respiration and bomb 
calorimeters are exact. There may be errors in the estimates 
of the amounts and heats of combustion of the materials 
actually oxidized. Variations due to irregularities of the physio- 
logical processes of the body are unavoidable and may materi- 
ally affect the results. For instance, the calculations assume 
that the quantities of material in the alimentary canal and the 4 
amounts of carbohydrates in the body as a whole are the same 
at the end as at the beginning of each day or. experiment, 
whereas they may differ considerably and the differences would 
materially affect the results. But it might be hoped that, if 
the methods are correct, these errors would tend to counter- 
balance one another in a series of experiments, and that, in 
the average of a sufficiently large number, the errors would 
thus be offset, so that the income and outgo would be very 
nearly the same. 
Exactly this is the case in the data here reported. ‘The 
variations for individual days, and even those for the individ- 
ual experiments, as shown in the detailed tables in this and 
the previous bulletins, are not inconsiderable, but considering 
the average of all the experiments the agreement is very close. 
Thus, in the 25 days of the seven rest experiments with ordin- 
ary diet with EK. O., according to the figures for the individual 
days the net outgo varies from 165 calories below to 194 calo- 
ries above the net income. Expressed in percentages of net 
income, the range here is from —6.5 to +9.1 per cent. Both 
these extremes occurred on the first days of the respective 
experiments, and in general, it may be said that the results for . 4 
the first day of an experiment are found to be less satisfactory 

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