THE RELATIONS OF METABOLISM TO FOOD-SUPPLY. 121 
Apparently Digested. Nitro. Gain 
. eR . 
ies Crude| Crude |_N. fr. | Nitro- Urine, ie 
Fat, | Fiber, |Extract,| gen, |Grms.| Gor, 
| Grms. Grms. | Grms. | Grms. 
Sheep I. 
Period 1 | Hay only ............... 13 .55)315 .72|470 .85/15 .02|13.83) 1.19 
«2 | Hay, peanut cake, sugar, 
and starch ............ 15 .27|134.11|560.71/13 .55/11.31) 2.24 
“3 | Hay, peanut cake, sugar, 
and paper pulp........ 13 .67/439 . 32/320 .21/13 .76|11 26) 2.50 
‘Shee Pe Hay and peanut cake..... 18 .57)171 . 12/345 .92/16 .25|14.45) 1.80 
eep II. 
Period 1 | Hay only ............... 11.76/171 .92|/276 .42!10.88] 8.45) 2.43 
“2 |Hay, peanut cake, sugar, 
and starch ............ 13.07] 77.48]/336.62| 9.54) 7.85) 1.69 
“3 | Hay, peanut cake, sugar, 
and paper pulp........ 15. 14/235 .31}198.46) 8.82) 7.62) 1.20 
even consistent with the view that cellulose has no effect upon 
the proteid metabolism. In other words, the results on Sheep I, in 
the first period, appear inconsistent with the other results. 
Kellner * has experimented with rye straw extracted with an 
alkaline liquid under pressure in the same manner as in paper- 
making and containing 76.78 per cent. of “crude fiber” and 19.96 
per cent. of nitrogen-free extract. The results as regards the pro- 
teid metabolism, compared with those on starch, are given in the 
upper table of p. 122. 
Taking the figures as they stand, and attempting no correction 
for the marked depression in the apparent digestibility of the nitro- 
gen resulting from the addition of the extracted straw or starch, 
they show a considerable effect by both in diminishing the proteid 
metabolism relatively to the supply in the food and thus causing 
an increased gain of nitrogen by the body. Any correction for the 
metabolic nitrogen of the feces, as in Weiske’s experiments, would, 
of course, tend to make the effect appear still greater. With the 
first animal, after taking account as well as possible of the slight 
differences in the fat digested in both periods and of the slight 
effect of the starch upon the digestibility of the fiber of the basal 
ration, the digestible matter of the extracted straw, five sixths of 
which was cellulose, appears to have produced more than twice 
as great an effect as an equal amount of starch. With the second 
* Landw. Vers. Stat., 53, 278. 
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