METABOLISM. 57 
Kellner’s experiments afford indirect evidence that both the 
asparagin and the ammonium acetate actually did stimulate the 
development of the ferment organisms, in the fact that the apparent 
digestibility of the carbohydrates of the food was increased. On 
the basal rations starch could be readily recognized in the feces, 
but under the influence of the two substances mentioned it dis- 
appeared. In the second experiment the increase in the amounts 
of crude fiber and of nitrogen-free extract digested was as follows: 
Nitrogen-free 
Crude Fiber. Extract. 
With ammonium acetate... 10.7 grms. 20.4 grms. 
With asparagin’........... 100 “ 20.0 “ 
Since we know that large amounts of the nitrogen-free extract 
are attacked and decomposed by organized ferments in the her- 
bivora, and that this is the chief if not the only method by which 
crude fiber is digested, we are justified in interpreting the above 
figures as demonstrating an increased activity of these organisms 
as a result of the more abundant supply of nitrogenous food. The 
bearing of this result upon the so-called depression of digestibility 
by starch and other carbohydrates is obvious, but is aside from 
our present discussion. 
Tryniszewsky * experimented upon a calf weighing about 175 
kgs., using in the second and fourth periods (the first period being 
preliminary) a ration of barley straw, sesame cake, starch and sugar, 
containing a minimum of non-proteids. In the third period one- 
third of the sesame cake was replaced by a mixture of asparagin, 
starch and sesame oil, computed to contain an equivalent amount 
of nitrogen, carbohydrates, and fat. Owing to differences in digest- 
ibility, however, the amounts of digested nutrients, and particu- 
larly of nitrogen, varied more or less. The results of the nitrogen 
balance per 100 kgs. live weight were: 
Nitrogen Digested. : 
. Nitrogen Gain of 
Metabolism,| Nitrogen, 
Proteid, | Non-proteid, Total, Grms. Grimms. . 
Grms. Grms. Grms, 
Period II....... PQ16  |iccaweswus 72.16 56.86 15.3 
ames WG errr 67.05 23.68 90.73 78.48 12.3 
FE TV veteisiees 90.86 |.......00- 90.86 76.36 14.5 
* Jahresb. Ag. Ch., 48, 513. 
