THE FOOD AS A SOURCE OF ENERGY. 297 
Metabolizabl 
Gromer, | “Energy, | orShobieble 
; . Cals. = 
Sample I, Ox D.. 9.493 7.382 77.76 
“ 11 “ Fee. mal 9.464 { ee pas 
Average, IT... 0.0... 0 [occ cece eee 5.298 55.96 
SumMMAry.—The foregoing results may be conveniently sum- 
marized in the table below, which shows the average gross energy 
per gram of organic matter, the percentage of this gross energy 
carried off unmetabolized in the various excreta, and the apparent 
metabolizable energy expressed both per gram of total organic 
matter and as a percentage of the gross energy: 
Apparent 
Gross Percentage Loss in Metabolizable 
En'gy Energy. 
er 
Tm. 
Or- Per 
anic Grm.| Per 
at- Or- | Cent. 
ter, | Feces.| Urine. | Methane. | ganic | _ of 
Cals. om Pee 
Gael 
Meadow hay...............0+-- 4.751/40.96| 5.71) 6.77 12.213/46.56 
Timothy hay...............005 4.670/47.27| 2.61 6 .50*|2. 037/43 .62 
Oat: Straw oo vee sa sied s castes ae © .14.816|56.80] 2.08) 5.32 |1.724)/35.80 
Wheat straw............6.- »+.-{4.743/58.22) 2.37 8,30 |1.475/31.11 
Extracted rye straw............ 4.251|12.75/—0.79) 12.46 |8.213)/75.58 
Beet molasses, Sample IT......../4.188) 9.93, 2.91) 11.31 |3.174/75.85 
Starch, Kiihn’s experiments. . qiuayaed 4,243/19.59}—0.92) 10.74 |2.995/70.59 
«c ’Kellner’s experiments: . 
Heavy rations..............-. 4,165/55.91)—2.07| —2.49 |2.028/48.65 
Medium rations............... 4.168)17.61)—0.66 9.21 |3.079|73.84 
Wheat gluten, Kellner’s experi- 
WNCNS ssid ic days eas Sa he eek SS 5.742/20.16] 13.08 0.08 |3.831/66.68 
Peanut GU, OX Die eco speed ciene 89 9.493|24.34/—1.08] —1.02 |7.382)/77.76 
Be EE sco Ye duane ete 4 9.464164. 77;—1.19}—16.10 |4.973/52.52 
es samme © pe nrer eeer aren nner 9.464/41.00} 1.37) —1.76 |5.623/59.39 
* Estimated. 
Digestible Organic Matter. 
As appears especially from the figures of the last table, the loss 
of energy in the feces is the one which is subject to the greatest vari- 
ation. In other words, the digestibility of a feeding-stuff is the 
