THE FOOD. 13 
probably. also to a large extent in the swine and horse, converted 
into sugars and resorbed in that form. 
Fermentations.—Reference has already been made to the fermen- 
tations taking place in the digestive tract. In the herbivora, and 
especially in ruminants, these fermentations play an important 
part in the solution of the carbohydrates which make up so large 
a portion of the food of these animals. These bodies undergo a 
fermentation which was first studied by Tappeiner * in the case of 
cellulose, but which has since been shown by G. Kithn ¢ to extend 
also to the more soluble carbohydrates. The products of this 
fermentation appear to be methane, carbon dioxide, and organic 
acids, chiefly, according to Tappeiner, acetic and butyric. Of these 
products, only the organic acids at best can be supposed to be of 
any value to the animal organism, and obviously it makes a very 
serious difference in our estimate of the.nutritive value of starch, 
for example, whether it is resorbed chiefly or entirely in the form of 
sugar or whether in a ruminant more than half of it, as in some of 
Kiikn’s experiments, is fermented. 
* Zeit. f. Biol., 20, 52. + Landw. Vers. Stat., 44, 569. 
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