THE FOOD AS A SOURCE OF ENERGY. 329 
a0 roe Ticested 
arbohydrate . 
Daria a Energy of ee 
Methane | of Total 
nN Grm. | Digested 
Garbo | ,Carbo- 
Crude Nitrogen- ivde 58 ydrates 
ber. | free, | Galas” | Peiggis 
Meadow hay I.................. 31.7 68.3 0.532 3.694 
a FE IMI a oa ee Be i tan hte 34.2 65.8 0.580 3.646 
f SOs DM idan ihc auigesia orate ae WO 35.0 65.0 0.579 3.647 
< AON Ties as oe sues ote coeh Bie eas dep 37.3 62.7 0.458 3.768 
id OO Mans johanna Ma eS 38.6 61.4 0.569 3.629 
se SY Bauaveaiad ania dames 40.4 59.6 0.597 3.657 
ee “ and oat straw.........) 41.9 58.1 0.574 3.652 
Clover ‘“ “ “ fe Seo ae 42.6 57.4 0.678 3.548 
Oat straw IT............. 0.222 47.8 52.2 0.595 3.631 
Wheat straw V.......... 000-005 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 isa 
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. 
CruvE 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. 
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