170 PRINCIPLES OF ANIMAL NUTRITION. 
Even on the most extreme assumptions it is only possible to 
regard the fat produced as derived wholly from the proteids of the 
food in three cases in which an excessive proportion of the latter was 
fed. If the probable digestibility of the foods used be considered, 
and Henneberg’s factor (51.4 per cent.) for the possible production 
of fat from proteids be used, the results show even more decidedly 
a formation of fat from carbohydrates. In a later paper,* in reply 
to criticisms, the authors state that they have reviewed and recal- 
culated many of their experiments with the result that, while the 
experiments with ruminants (sheep and oxen) failed to furnish con- 
clusive evidence of the formation of fat from carbohydrates, a 
large number of those with pigs unquestionably showed such for- 
mation. 
In view of their historical interest it has seemed desirable to 
give the results of Lawes & Gilbert’s experiments in some detail, 
although at the time they hardly secured the recognition which 
was due them and Voit’s views became the generally accepted 
theory for the next twenty-five years. Notwithstanding the latter 
fact, however, results of experiments on herbivorous animals speed- 
ily began to accumulate which were difficult to reconcile with Voit’s 
hypothesis. 
Experiments on Ruminants.—Experiments on milch cows were 
made by Voit himself, as already noted. G. Kithn & Fleischer + 
a little later discussed the results of two of their extensive feeding 
experiments on milch cows in their bearing on this point, and M. 
Fleischer { did the same with the results of similar experiments 
made by Wolff and himself.§ Their results are tabulated on the 
opposite page. 
Neither Voit’s nor Fleischer’s results are such as to require the 
assumption of a formation of fat from carbohydrates. Those of 
Kiihn & Fleischer show a small excess of fat in the milk over that 
producible from the fat and proteids of the food, but the authors 
* Jour. Anat. and Physiol., 9, 577; Rothamsted Memoirs, Vol. IV. 
+ Landw. Vers. Stat., 10, 418; 12, 451. 
t Virchow’s Archiv, 51, 30. 
§ Jour. f. Landw., 19, 371, and 20, 395. 
