14 THE ECONOMICS OF FEEDING HORSES 



starch in a seed-grain or tuber is transported to other 

 parts of the plant where food is needed. Maltose is an 

 unimportant member of the sugar group in foodstuffs, 

 but it is probably this form into which starch is changed 

 and transferred to the growing sprouts of a germinating 

 seed ; and the process of malting consists in allowing 

 barley grains to germinate to such an extent that a large 

 amount of maltose is produced. More important sugars 

 are cane-sugar, or saccharose, found in large amount in 

 the sugar-cane and sugar-beet ; glucose, dextrose, or 

 grape-sugar, occurring in various fruits ; and Isevulose, 

 found in honey and fruits, often along with glucose. 

 Another important carbo-hydrate is cellulose, which 

 forms the cell-wall or envelope, inside which the food 

 substance of plants is stored. In order that the cell 

 contents may be made use of, the cellulose envelope 

 must first be broken down or digested, and the power to 

 do this varies greatly in different animals. In the older 

 more fibrous parts of plants the cellulose becomes harder 

 and less capable of digestion, or is actually converted 

 into woody fibre, or lignin, which is practically insoluble. 

 Other less important carbo-hydrates are the gums and 

 pectin bodies, which occur in plants in small amounts ; 

 but for feeding purposes they are practically negligible. 



The Fats and Oils are chiefly in the forms of olein 

 and palmitin, compounds of fatty acids (oleic and 

 palmitic), with glycerine. They are composed of the 

 same elements as the carbo-hydrates — namely, carbon, 

 hydrogen, and oxygen; but they require much more 

 oxidation {i.e., will combine with a much larger quantity 

 of oxygen) to break them down into their ultimate 

 products in the body — carbon dioxide and water. For 

 this reason, and in this proportion, they are better 



