120 PRINCIPLES OF ANIMAL NUTRITION. 
Lehmann * experimented upon a sheep by adding respectively 
crude fiber, prepared from wheat straw, and starch to a basal ration. 
The results were not entirely sharp but showed plainly a decrease 
of the proteid metabolism on the crude fiber ration which was 
equal approximately to 61 per cent. of that secured by the use of 
starch. In a second series of experiments, Lehmann and Vogel f 
compared the effects upon the proteid metabolism of sheep of cane- 
sugar and of the digestible non-nitrogenous matters of oat straw. 
On the basis of a very careful discussion of the experimental errors, 
they show that the latter substances have a marked effect in diminish- 
ing the proteid metabolism, and in particular that if we ascribe this 
effect exclusively to the digested nitrogen-free extract, as Weiske 
does, we must admit that the latter produced an effect from two 
to nine times as great as that of cane-sugar. They therefore con- 
clude that their results show qualitatively an effect of the digested 
cellulose upon the proteid metabolism. Reckoning the digested 
nitrogen-free extract of the straw as equivalent to sugar, they com- 
pute from the average of all their experiments that the cellulose 
produced 75.7 per cent. as great an effect as the sugar, but they do. 
not regard this. quantitative result as well established. 
Holdefleiss {| experimented upon two sheep, feeding in a first. 
period meadow hay exclusively. In the second period one half of the 
hay was replaced by a mixture of peanut cake, starch, and a little 
sugar, while in the third period the starch was replaced by paper 
pulp. In one case a fourth period was added in which the paper 
pulp and sugar were simply omitted from the ration. The digested 
nutrients and the proteid metabolism per day are tabulated on p.121. 
Converting the small differences in the amount of crude fat 
digested into their equivalent in nitrogen-free extract by multipli- 
cation by the factor 2.5, Holdefleiss computes from a comparison 
of the second and third periods that the digested crude fiber pro- 
duced on the first animal 80.1 per cent. and on the second animal 
84.2 per cent. of the effect of the starch. A somewhat higher value 
would be obtained from a comparison of the first and second periods 
in the case of Sheep IT, while on the other hand a comparison of the 
corresponding periods with Sheep I gives a much lower value, and is 
* Jour. f. Landw., 37, 267. t Ibid., 37, 281. 
t Bied. Centr. Bl. Ag. Chem., 25, 372. 
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