COMPOSITION OF FEEDING-STUFFS 15 



sugar being the usual sugars formed. The pento- 

 sans and the incrusting material, both of which 

 have already been mentioned, may be separated 

 into two portions. One remains undissolved, as 

 was seen in the preparation of the crude fibre, 

 whilst the second and greater portion goes into 

 solution, and must therefore be reckoned as nitrogen- 

 free extract. 



The organic acids are generally only present in 

 small quantities in the natural food-stuffs. They 

 may be there partly in the free state and partly 

 combined with potash, soda, or lime to form salts. 

 The chief representatives in the vegetable kingdom 

 are malic, tartaric, citric, and oxalic acids. Those 

 feeding-stuffs which have undergone acid fermenta- 

 tion contain fairly large quantities of lactic acid 

 along with butyric and acetic acids, which are the 

 results of bacterial activity. 



Roots, tubers, and by-products of these — such 

 as potato slump, slices of sugar-beet, molasses — are 

 distinguished by the quantity of nitrogen-free ex- 

 tract which they contain. The cereal grains and 

 the meals made from them take the next place, 

 whilst some products of the animal kingdom — meat- 

 and fish-meal, dried blood, etc. — come last. 



(7) The mineral substances^ or ash. 

 To determine the amount of mineral matter or 

 ash in a feeding-stuff, a known quantity of it is 



