THE FOOD AS A SOURCE OF ENERGY. 329 
we ata Digested 
aTDO.: ti * 
Contain Re Energy of Eee ae 
ee of Total 
rm, i 
Digested | TCstbo 
Crude Nitrogen-| ar as hydrates 
Miber- | ptract. | Cale | Pata” 
Meadow bay levis ser onue-15es 31.7 | 68.3 | 0.532 | 3.694 
HE 8 IMM oe no eeiayate ls a pee ev cites 34.2 65.8 0.580 3.646 
. OO Whisiectiew ds xine eae 4 35.0 65.0 0.579 3.647 
OO NAD sai bd, Secs eesi es casi 37.3 62.7 0.458 3.768 
ee SOOM easiete ans ok ape Minton’ 38.6 61.4 0.569 3.629 
ta OO MBs sa sie cduatiog ae aed ar 40.4 59.6 0.597 3.657 
“ and oat straw..... 41.9 58.1 0.574 3.652 
Clover “ “ “ EG ea Sa 42.6 57.4 0.678 3.548 
Oat: straw TT... oi oa sus ences eae ces 47.8 52.2 0.595 3.631 
Wheat straw V..........--...0-5 59.1 40.9 0.894 3.332 
A comparison of the methane production with the digestibility 
of the feeding-stuffs shows in general that the former is greatest 
when the latter is least, that is, with the feeding-stuffs which tend 
to remain longest in the digestive tract. Here too, however, excep- 
tions occur, and it would appear that the physical condition of the 
feeding-stuff is not without its influence. The exceedingly com- 
plicated nature of digestion in ruminants, and the fact that it is a 
chemical rather than a physiological process, and is therefore sub- 
ject to considerable variations according to the nature and amount, 
of the food, render it difficult, if not impossible, with our present 
knowledge to compute very trustworthy averages for the amount 
of energy carried off in this way. 
Crupe Finer. Ruminants.—Both the ultimate composition and 
the heat of combustion of the digested nitrogen-free extract have 
been shown to agree quite closely with those of starch, and the 
nutritive value of the former has commonly been assumed to be 
the same as that of the latter. If we are justified in somewhat 
extending this, and assuming that the nitrogen-free extract of 
coarse fodders suffers the same loss by the methane fermentation 
as does starch, the figures of the preceding paragraphs supply 
data for computing the corresponding loss suffered by the 
crude fiber. 
