388 PRINCIPLES OF ANIMAL NUTRITION. 
The average energy metabolism thirty-six minutes after eating, 
computed as previously described, is somewhat more than 9 per cent. 
greater than that shortly before eating, and a still further increase 
was observed at the end of three hours. The effect is precisely 
similar to that observed in Magnus-Levy’s experiments. It was 
not, however, followed through the twenty-four hours, as in some 
of those experiments. 
Comparison or Hay anp Grain.—It was found further that 
coarse fodder (hay) produced a much more marked effect than did 
grain. The following comparison of the average of the experi- 
ments of Period c on an exclusive hay diet with that of Period j on 
a mixed ration illustrates this fact: 
Period c. Period }. 
Time since last fed .............. 2.6 hrs. 2.8 hrs. 
Ration: : 
PLAY cess Sera Rawle nies ve wae About 10.5 kgs.* 4.75 kgs. 
Oats) Mae sckdt te pede aaa es gaan | oe Meee eaalee ee eee y 6.00 “ 
SOUP W diye 2.4 tase ogee tue: 5 piavein ococencun: Ss Ee wud a(Bs don tess) tie Ghe NG 1.00 “ 
Total digested nutrients (fat x 
DB) es tices, whee aevoigteod sig ss 4125 grms.}+ | 5697. grms.f 
Per kilogram and minute: 
Oxygen consumed ............ 3.9837 c.c. 3.6986 c.c. 
Carbon dioxide given off ....... 3.6586 “ 3.6695 “ 
Energy set free (computed)..... 19.552 cals. 18.339 cals 
Notwithstanding the greater total weight of food consumed in 
Period /, and the much larger amount of digestible matter contained 
in it, the oxygen consumption and the computed amount of energy 
liberated are notably greater in Period c, on the hay ration. The 
average time which had elapsed since the last feeding, as well as the 
external conditions, having been substantially the same in both 
periods,t and the animal having been in a state of rest, the effect 
is ascribed to an increase in the expenditure of energy in diges- 
tion due to the difference in the physical properties of the two 
rations. This difference is chemically characterized by the greater 
* The exact amount of hay eaten is not stated. The digestible matter 
is computed from the composition of the hay by the use of Wolfi’s coeffi- 
cients. 
t+ Computed in the manner described above, p. 386. 
} It varied considerably in the individual experiments composing Period f. 
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