178 PRINCIPLES OF ANIMAL NUTRITION. 
id |Equivalent| Fat of | Maximum Fat 
Animal. | Period. Maceo, . Fat, Food, ere eae _cinally 
Grms. Grms. Grms. Ging. | Grme. 
I 2a 373.6 259 86 345 423 
I 2b 382.0 |. 265 81 346 332 
II 2 297.4 | 206 77 283 434 
Til 2 104.4 72 60 132 281 
IV 2 126.9 , 88 60 148 160 
Tir 3 506.9 351 69 420 375 
IV 3 548.8 380 74 454 388 
III 4 980 _ 679 84 763 526 
Vv 2a 232 161 42 203 396 
Vv 2b 268 186 42 228 407 
Vv 3 149 103 39 142 703 
VI 2a 218 151 40 191 304 
VI 2b 232 161 35 196 381 
VI 3 186 129 43 172 507 
In most of these experiments the rations were purposely made 
poor in proteids and fat, and in all such cases, with one exception, a 
formation of fat from carbohydrates is clearly demonstrated. In 
three cases in which large amounts of proteids were fed, as well as in 
some similar experiments not included in the above table, it was 
possible to account for the fat production otherwise, but such nega- 
tive results in no degree weaken the positive teaching of the remain- 
ing trials. , 
The more recent investigations of Kellner e¢ al.* at the same 
Station, in which starch was added to a basal ration, although under- 
taken primarily for other purposes, likewise show the formation of 
an amount of fat inconsistent with the hypothesis of its production 
from the fat and proteids of the ration only. 
The failure of Pettenkofer & Voit to obtain affirmative results 
in their earlier experiments appears to be largely explicable, in the 
light of more recent knowledge, from the conditions of the experi- 
ments themselves. Pfltiger + has recalculated their experiments on 
the same basis as those upon the formation of fat from proteids 
(see p. 109), and has pointed out that in the majority of cases the 
total food was, according to his computations, scarcely more than 
sufficient for the maintenance of the. organism, thus leaving no 
excess of any kind for fat production. Moreover, out of those ex- 
* Landw. Vers. Stat., 68, 1. 
t Arch. ges. Physiol , 52, 239. 
