ABSORPTIOX 



2S7 



of absorbing fat from different food substances, and demonstrates 

 the relatively weak powers of the horse in this respect : 



All the above foods in the matter of fat, and we shall see 

 presently in the matter of carbohydrates and protein, are richer 

 and more nourishing for the ruminant than the equine, owing 

 to the different powers of absorption in the two classes. 



Food-Absorption. — At this point it is necessary to digress 

 somewhat, and glance at the question of the absorption of the 

 various proximate principles of food — viz., protein, fat, and 

 carbohydrate. 



The economic feeding of animals has led to the chemistry 

 of food-absorption being inquired into by laborious series of 

 experiments which have been carried on for years. Each class 

 of animal has a different power of utilising the same food ; for 

 example, grass and hay are far more nourishing to the ox and 

 sheep than to the horse, and the ox can utilise more than the 

 sheep. 



If a food were entirely digested and absorbed, there would be 

 no faeces excepting the waste liquid secretion of the digestive 

 tract. There is, of course, no ordinary food substance capable 

 of complete absorption ; there are indigestible substances which 

 cannot be dealt with and are excreted ; and with the herbivora 

 these must necessarily be very large. But entirely apart from 

 indigestible matter, there is only a proportion of each of the 

 proximate principles of a food which can be absorbed. The 

 protein, fat, carbohydrate, and cellulose of every food substance 

 has a distinct rate of absorption in each class of animal. Taking 

 hay as an example, the horse can, as a mean, digest : 



Per Cent. 



Protein ------- 57 



Fat --------24 



Carbohydrates 55 



Cellulose -.--«.. 36 



In no way can a given amount of hay be rendered more efficient 

 by causing more to become absorbed. Absorption of the food 



