FOOD OF ANIMALS. l6l 



much as 70 per cent, of some kinds of straw. Notice that this 

 class of compounds does not form one of the leading classes 

 of constituents of the animal body. 



FIBRE. Woody fibre this is sometimes called. A young 

 plant is easily bent and pulled to pieces ; it contains little 

 fibre. As the plant grows older it becomes stiffer and tougher, 

 because the fibre increases. Wood that we burn is nearly all 

 fibre, and we know how tough and indigestible it is. There- 

 fore, we conclude that a large amount of fibre makes a food 

 less valuable. The fibre is formed from the starch and sugar 

 by the addition f)f carbon. It forms the walls of the cells of 

 plants, and therefore is sometimes called by the name " cellu- 

 lose.' 



ASH. The ash or mineral matter is found in all parts of 

 the plant, but, as has been stated already, the most valuable 

 ash is stored up in the seed or grain. The cell walls of the 

 plant fill up with carbon and ash as the plant grows older, and 

 therefore the sap cannot flow through so easily, the cells dry 

 up gradually, and the plant becomes stiffer and tougher. 

 REFKRKNCES : 



The teacher who wishes to study the subject matter of this chapter 

 further may consult " Feeds and Feeding," by Henry, " Cattle Feeding," 

 by Armsby. 



