NET AVAILABLE ENERGY—MAINTENANCE. 415 
As compared with the fasting state, the 883 Cals. of metaboliz- 
able energy supplied, for example, in 1000 grams of meat diminished 
the loss of energy by the body by 1041—250=791 Cals. The latter 
quantity, then, represents the extent to which the 883 Cals. supplied 
in the food aided in maintaining the stock of potential energy in the 
body, while the remaining 92 Cals. was consumed in the work of 
digestion and assimilation as defined on previous pages; that is, it 
increased by this amount the heat production of the animal. Ac- 
cordingly we compute that in this case 89.6 per cent. of the metabo- 
lizable energy of the meat was available, while the digestive work 
consumed 10.4 per cent. Computing the other experiments in the 
same way we have— 
. Gain Over . 
Metabolizable . Net Avail- 
Fasting a: 
E f ¢ bility, 
Food. Cals f Metabolism r Per Cenk z 
442 510 | «(115.4 
883 791 89.6 
1325 1079 81.5 
From Rubner’s experiments * with proteids (see p. 106) the 
following figures are computed in the same manner as those above: 
Gain. nist 
Metab- | Heat {~—————_|_ ayei. 
Food, ae Ea Over ability, ee 
Grms. | of Rady noe Total, | Fasting ae Deg, ©.” 
Cals. . Cals.’ | Metab- ent: 
olism. 
Cals 
0 0 | 573* | —573 |.......]...000- 19.2 
BEBE pe Coens { 415 | 367 | 596* | —229| 344 | 93.74] 19.6 
éi | 0 o | 793* | —793 |.......)....... 18.0 
yee | 740 | 654 | 825* | —171 | 622 | 95.15] 19.2 
| 0 o | 931* | —931 |.......].....0- 14.9 
Extracted meat }| 740 | 939 | 959* | — 20 | 911° |'97.03 | 15:6 
0 o | 261+ | —261 
Meat......... 390 | 347 | 334¢] + 13 | 274 | 78.98 
350 | 309 | 379+ ' — 70| 191 | 61.80 
a {| 0 0 | 528 | —528 
eo Ee 580 | 512 | 681¢ | —169 | 359 | 70.12 
* Computed. T Calorimetric determinauon. 
* Zeit. £. Biol., 22, 43-48; 30, 117-135. 
Digitized by Microsoft® 
