12 SCIENTIFIC FEEDING OF ANIMALS 



By this means, unfortunately, not only the fat 

 but other substances — such as wax, colouring 

 matters, and in some cases organic acids, which 

 are soluble in ether — are weighed along with the 

 fat. The separation of these compounds from the 

 fat is not easy, so in order to indicate that the fat 

 is not pure it is customary to call it " crude fat " 

 or " ether extract." Oily seeds and waste animal 

 products, such as greaves and tallow refuse, are 

 amongst the food-stuffs containing the most fat. 

 Then come the oil cakes, oil cake meals, brewers' 

 grains, and other by-products from distilleries, 

 flour mills, and starch manufactories. The cereal 

 grains, such as oats and maize, and the leguminous 

 seeds, such as soja beans or lupines, take the next 

 place, whilst roots, tubers, green fodders, hay and 

 straw are amongst the poorest in fat. 



(5) Crude fibre. 



If a small quantity of finely-ground food material 

 be boiled successively with given quantities of 

 dilute sulphuric acid, water, dilute caustic potash, 

 and again with water, a residue is left, which, after 

 washing with alcohol and ether, may be dried and 

 weighed. This residue consists principally of crude 

 fibre along with a little crude protein and mineral 

 substances, and if these last two are estimated 

 separately in a portion of the residue, and their 

 weight deducted from the total weight, then the 



