326 PRINCIPLES OF ANIMAL NUTRITION. 
the production of hydrocarbons was diminished. Kellner suggests 
that the latter effect may have been due to a partial suppression 
of the organisms causing the methane fermentation by other species, 
and suspects that the presence of large amounts of carbohydrates 
along with little protein favors this result. At any rate, the con- 
ditions are evidently unusual if not abnormal. 
In Kiihn’s experiments the starch was added to a ration of 
coarse fodder. The nutritive ratio was wide, but the absolute 
amount of carbohydrates was much less than in the two experiments 
by Kellner just mentioned, less starch appeared to escape diges- 
tion, and the production of hydrocarbons was increased in every 
case. The following are Kihn’s * results: 
Difference in Carbohydrates 
Digested. Difference in 
Energy of 
Methane, 
Crude Fiber, | Nitrogen-free Cals. 
rms. Extract, Grms. 
Ox Til, Period 2...............02- —220 1529 706.2 
OS Ny ~ So leniaaeuls eoewanaates ¢ —180 1408 856.7 
CO OM SS 2G aa wie ania eee —195 1537 752.6 
BED MIE EOS LOD here unites cea eayeheaas —130 1539 665.5 
ate ee Se eee ees —176 2619 1181.0 
“ VI, OB Db iereva itn aed ehies anaes. —146 1468 729.5 
SE VT 8 2D a ens vac lara cosine coca hanes — 88 1554 649.9 
OVI, Bae new es vowed ceases —156 2587 1407.0 
Lopals> sucinas cata ante ae oases —1291 14241 6948 .4 
Assuming as before the equivalence of crude fiber and nitrogen- 
free extract as regards the production of hydrocarbons we have 
6948 .4 Cals. + (14241 — 1291) =0.537 Cals. per gram, 
4.185 Cals. —0.537 Cals. =3.648 Cals. per gram. 
Determinations by Lehmann, Hagemann & Zuntzt of the 
amount of methane produced by the horse will be considered in 
connection with the metabolizable energy of crude fiber. Zuntz t 
has pointed out that the fermentation of the food in the horse takes 
place largely in the coecum and after the more digestible carbo- 
hydrates have been resorbed. Accordingly he regards the metabo- 
* Loc, cit., 44, 570. 
+ Landw. Jahrb., 23, 125. 
t Arch. ges. Physiol., 49, 477. 
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