INTERNAL WORK. ; 379 
the metabolism was still slightly above its fasting value after eight- 
een hours. The respiratory quotient in every case sank to a value 
closely corresponding to that for the oxidation of pure fat. 
The experiments do not permit an exact estimate of the total 
increase of the metabolism during the twenty-four hours, since 
the observations were not always made at hourly intervals and 
but few of the trials extended over a full day. By selecting, 
however, the two in which the data are most complete and com- 
puting as accurately as may be the average rate of consumption 
of oxygen per minute, it is possible to obtain an approximate 
expression for the total heat production. For this purpose the 
average oxygen per minute is multiplied by 1440 and this product 
by the calorific equivalent of the oxygen, viz., 3.27 Cals. per gram 
in this case, and the following results obtained, the heat production 
during fasting being in each instance that found in the particular 
experiment under consideration: 
Heat Production in 24 Hours. 
Fat Energy 
No. of 
: Eaten, f Food, I . 
Experiment. Grms’ | Cals.’ | Fasting, | With —— 
Cals.” Heed Per Cent 
ais. er . 
Cals. of Food. 
100: dccex ea tere ss 131.6 1250 972 991 19 1.53 
64 and 68....... 305.5 2902 1055 1142 87 2.99 
CARBOHYDRATES.—Carbohydrates produced a more marked 
effect upon the metabolism than did fat, and one which showed 
itself more promptly. In the experiments on the dog the food 
consisted of rice, either alone or with the addition of small amounts 
of fat, sugar, or meat; in other words, the animal was on a mixed 
diet in which carbohydrates predominated. 
On the average of a series of six experiments in which the food 
consisted of 500 grams of rice, 200 grams of meat, and 25 grams of 
fat, the metabolism increased by fully 30 per cent. within the first 
hour and continued to increase more slowly until the maximum of 
39 per cent. was reached at the sixth to eighth hour. From that 
time it decreased to 25 per cent. in the twelfth hour and then rather 
suddenly dropped nearly to the fasting value. The respiratory 
quotient rose from 0.78 during fasting to 0.90 in the first hour, and 
