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MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



its capital as small as practicable. It would therefore seein that the amounts of material 

 oxidized in the experiments with the two kinds of diet would give a somewhat critical test of the 

 power of the body to utilize the energy of alcohol, either directly for muscular work or indirectly 

 to save the energy of other materials for that work. We may. then, determine the relative 

 efficiency of the alcohol in supplying energy in these experiments by comparing the amounts of 

 energy in material oxidized. If the amounts are the same with and without alcohol the inference 

 is that the energy of the alcohol was utilized as effectively, so far as simply the economy of 

 energy is concerned, as that of the fats and carbohydrates: but if more energy is metabolized 

 with the alcohol we must conclude that it is inferior as a source of energy in a diet for muscular 

 work. We may take, for instance, the pair of experiments Nos. 11 and 12, in which the man 

 was at hard work. (See Table CXX, p. 390.) His body used, in No. 11. with ordinary diet, 

 3,901 calories of energy per day. The food digested and absorbed from the diet supplied 3,510 

 calories, and the body burned enough of its previously accumulated material, protein and fat, to 

 supply the lacking 391 calories. 



In the corresponding alcohol experiment. No. 12. enough of the fats, sugar, and starch of the 

 previous diet to furnish about 500 calories of energy was taken out and replaced by sufficient 

 alcohol to furnish approximately the same amount, 500 calories. It happened that the total 

 energy in the alcohol ration was about 30 calories the larger. Furthermore, the availability of 

 the food proved to be slightly larger, so that the whole available energy of the alcohol ration was 

 3.t)14 calories. The amount of work done and the other conditions were practically the same as 

 in the previous experiment. The body transformed 3.922 calories and in order to do so drew 

 enough from its own store to furnish 308 calories. 



According to these figures the body burned a trifle more material in the alcohol experiments 

 than in the others — enough to furnish 3.922 instead of 3,901 calories of energy. But the alcohol 

 diet furnished, with the alcohol, a somewhat larger amount of total energy, and furthermore a 

 somewhat larger proportion of the nutrients of the ordinary food was digested, so that the body 

 had 104 calories more of available energy. The fact that it drew S3 calories less from its previously 

 stored material in this experiment than in No. 11 indicates that it used its energy economically. 

 In each of these two cases the daily amount of external muscular work measured was equiv- 

 alent to not far from 200 calories. In the first experiment all of this came from ordinary 

 food. It may be that in the second experiment likewise it all came from the reduced supply of 

 the ordinary food, and that none of the energy actually transformed into muscular work came 

 from the alcohol. There is, however, no reason to suppose that the body made any distinction 

 between the energy from the alcohol and that from the other fuel, and even if it did so it made 

 just as good use of the energy of the alcohol to meet its other needs as it did of the energy of the 

 ordinary nutrients. 



The test of the comparative economy of the two diets so far as concerns the supply of energy 

 is found in the amount of energy of material oxidized. This was 20 calories, or about 0.6 per 

 cent the larger in the alcohol diet. This is far inside the limit of experimental error. Indeed, 

 the quantity of energy given off from the body as measured by the respiration calorimeter was 

 5 calories larger with the ordinary than with the alcohol diet. (See Table CXX of the Appendix.) 

 Of course such differences have practically no significance in physiological experimenting. 



The results of the experiments in their bearing upon the subject are summarized herewith: 



Average amounts of energy in mutt rial oxidized. 



