THE FOOD AS A SOURCE OF ENERGY. 287 
the body and so is to be deducted from the total energy of the 
food to obtain its metabolizable energy. 
Experiments on timothy hay made by the writer,* in which the 
amount of methane excreted was estimated from the amount of non- 
nitrogenous nutrients digested, gave the following results, the cor- 
rection for the gain or loss of nitrogen being computcd in a slightly 
different way from that explained above: 
ENERGY PER GRAM ORGANIC MATTER. 
Experiment I. | Experiment II.|Experiment VI. 
Cals Cals. Cals. 
Bteerd..e wicscnin aa aiedes exesoh< 2.104 1.838 2.139 
Dc ratte id ba nen Oat A Ra Gy oh 2.007 2.164 2.175 
Te: PED Sesto sh ace See gE tian 1.904 1.824 2.176 
AVETAZE.. Le ee eee 2.005 1.942 2.163 
Average of all............. 2.037 
It should be noted that the above figures are, as already stated, 
approximate only. The energy of the methane was estimated, while 
the determinations of the energy of the urine were not, in all cases, 
satisfactory. We are probably justified, however, in regarding 
the results as a close approximation to the truth. 
Coarse FoppErs ADDED TO BasaL Ration.—As an example of 
this class of experiments we may take Periods 4 and 7 with Ox H.t 
The rations in the two periods were as follows: 
Total Weight. Containing Organic Matter. 
Period 4, | Fe a 7, | Period 4, | Period 7, | Difference, 
Kgs. Grms. Grms. rms. 
Meadow hay .............. 3198 6495 3297 
Molasses-beet pulp ........ 2386 2413 27 
Peanut meal.............. 818 835 17 
6402 | 9743 .| 3341 
* Penna State Experiment Station, Bull 42, p. 153. 
f Loc cit., 53, 278-335. 
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