40 MANUAL OF CATTLE FEEDING. 



DJgestll'ditij, — Cellulose was long tlioiiglit to be indiges- 

 tible. 



Ilaubner ^' was tlie first to show that this belief was er- 

 roneous, and that the ruminants were capable of digesting 

 large quantities of this substance. Ilis results have since 

 been verified in innumerable digestion experiments, wdiich 

 have shown that cellulose forms an important ingredient 

 in the fodder, not only of rmiiinants, but of all our herbi- 

 vorous domcbtic animals. 



The proportion of cellulose which is digested varies very 

 considerably according to the kind and quality of the fodder 

 and the species of animal to which it is fed. 



Of the cellulose of the ordinaiy coarse fodders, from 

 about 30 to ^0 per cent, is digested by ruminants, while the 

 cellulose of the cereal grains seems nmch less digestible. 

 In general, the j^ounger and more tender a feoding-stuft is, 

 the greater is the amount of cellulose which is digested, 

 while in old and woody plants, in ^\ Inch much lignin is 

 formed, its digestibility is considerably less. The lignin 

 itself appears to be entirely indigestible. 



Dfftsrmination, — The amount of cellulose in a fodder 

 is usually determined by successively boiling the finely 

 divided material with dilute acid and dihite alkali, and 

 washing with alcohol and ether. These solvents remove 

 the other constituents of the fodder and leave the (impure) 

 cellulose behind. The residue, after deduction of the 

 small quantities of ash and albuminoids which it still con- 

 tains, is designated as orude fibre. 



It is by no means pure cellulose, but is chiefly a mixture 

 of the latter with lignin. The crude fibre obtained from 



* Amts- und Anzefgeblatc f. d. landw. Vereine des Kom'greichs 

 Sadisen, 1B54, Ni. 6; also, ZeiUclir 1 D. Landw. 1805, 17 T. 



