14 THE SCIENTIFIC FEEDING OF ANIMALS 



latter reappears as a cleavage product. Not affected by iodin. Reduces 

 Fehling's solution in the presence of heat (red precipitate). 



Cane sugar (C12H22O11) occurs in quantity in sugar cane and sugar 

 beets. Many other plants contain small quantities (green rye, sweet corn, 

 sweet millet, meadow grasses, vetches, potato tops and immature pota- 

 toes). Also in the grains and other seeds, in seed hulls and in sweet 

 fruits. When broken down in the process of digestion it forms grape 

 sugar and fruit sugar. 



Milk sugar (C12H22O11) (lactose) under the influence of enzymes (dia- 

 stase) and the absorption of water is spMt up into galactose and glycose. 

 Occurs in milk but not in vegetable feeding stuffs. The latter, however, 

 are often rich in galactose-producing substances (galactan, paragalactan, 

 seminin, lactorin). Thus sugar beets contain galactan; beans, peas, 

 vetches, palm cake, cocoanut cake contain paragalactan and seminin. 

 Vegetable substances containing galactose appear in plants as mucilages, 

 pectin substances and gums. According to Muntz they are always present 

 in these substances in sufficient quantity to serve as raw material for the 

 production of milk sugar. 



The following carbohydrates have also been demonstrated in plants: 

 Malt sugar [(C12H22O11) malt] ; raffinose (CisHggOie) in cotton seed and 

 sugar beets; inulin(a form of starch which, however, does not stain blue 

 with fuchsin) in fleshy tubers and roots — topinambur (artichoke), arabin 

 (a vegetable gum) and sinistrin (grain of barley) and vegetable mucilages 

 (in various seeds and tubers). 



Pectin substances are a mixture of pentoses (beets, etc., fleshy fruits). 



The pentosanes occur as wood gum (xylan), are widely prevalent and 

 frequently in great abundance (brewers grains contain 29 per cent, slops 

 from distilled rye 16 per cent, straw 25 per cent, meadow hay 18 per cent, 

 clover hay 10 per cent, corn cobs 34 per cent, of the dry matter). Cattle 

 digest 62 per cent of the pentosanes, sheep 55, horses 40, swine 45 and 

 poultry 25 per cent. The digestibility of the pentosanes diminishes as 

 the starch content of the food increases. 



b. Organic Acids 



Lactic acid (CsHgOg) occurs in germinating seeds, distillery slops and 

 particularly in ensilaged or otherwise fermented vegetable feeding stuffs, 

 in quantities exceeding 3 per cent. In moderate quantities lactic acid aids 

 digestion and is said to favor milk secretion (Pott). When fed in 

 large amounts, injurious effects may follow, especially if the fermentative 

 processes were not properly regulated or controlled and other acids (ace- 

 tic, propionic, valerianic, capronic) are present. 



These latter are very apt to cause digestive disturbances, influence milk 

 secretion and impart a bitter taste to the milk, which latter is ascribed to 

 the fact that fermentative micro-organisms are discharged from the alia- 

 mentary canal and through carelessness or other causes contaminate the 



