140 PRINCIPLES OF ANIMAL NUTRITION. 
est fasting values previously obtained, Moreover, much of the 
nitrogen of his food was in the non-proteid form, the proteid nitro- 
gen being estimated at only 0.03 gram per kilogram live weight. 
Cremer & Henderson * have attempted to reproduce Sivén’s 
results in two experiments upon a dog, the total amount of food 
being equal to or slightly less than the estimated requirements of 
the animal. Under these conditions they were unable to reach 
even as low a minimum as did Voit & Korkunoff. On the other 
hand, Jaffa,} in a dietary study of a child on a diet of fruits and nuts 
(so-called frutarian diet), observed a gain of nitrogen by the sub- 
ject with only 0.041 gram of food nitrogen per kilogram body weight. 
Tue Minimum For Herpivora.—The ordinary food of our 
domestic herbivora contains an abundance of non-nitrogenous 
matter and relatively little protein. It is impossible, for obvious 
reasons, to determine the fasting metabolism of ruminants, and 
the basis for comparisons like those made above is therefore 
largely lacking. There is, however, abundant evidence to show that 
only a comparatively small amount of proteids is necessary to 
maintain the nitrogen equilibrium of cattle in particular, although 
exact data as to the least amount required are still lacking. 
The early experiments of Henneberg & Stohmann f upon the 
maintenance ration of cattle furnish the following examples of the 
sufficiency of a very small proteid supply, the results being com- 
puted per 500 kgs. live weight per day: 
Digested. Gain of 
ones 
F Non-nit y Animal, 
eyage [owns] cine 
Ox I: 
PeriGd) 1 vsiis scenic ase Se 178 4247 4.0 
HED caob dicta, dra ay eiereaneh aad 259 3546 21.0 
Bee Brava tad wetsiangaasd sia lenals 209 3926 11.0 
Oz II: 
Period 22 ee edissieae sees ns 278 3607 19.5 
* Zeit. {. Biol., 42, 612. 
+ U.S. Dept Agr., Office of Expt. Stations, Bull. 107, 21. 
¢ Beitriige zur Begriindung einer rationellen Fiitterung der Wiederkaiier, 
Heft I. 
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