CONSTITUENTS OF FOOD. 95 



feeding values of starch and cane sugar are almost identical. 

 Muntz has shown that starch and sugar are almost entirely 

 digested by horses, and that the carbo-hydrates of grain are 

 much more soluble than those of hay, and especially, of straw. 



The carbo-hydrates and fat in the food not only build up fat 

 in the tissues and furnish energy in other ways, but they also 

 retard the waste of nitrogenous tissue (muscle, etc.). We can 

 easily understand that with a food poor in carbo-hydrates and 

 fat, the demands of the system may entail increased waste of 

 nitrogenous tissue. 



The fact that fat horses can live far longer than thin ones, 

 when both are deprived of all food except water (p. 127), shows 

 that a food rich in fat-formers supplies much more energy 

 than a food rich in muscle-formers. 



It is a matter of common knowledge that the fat of pigs and 

 cattle, used for human food, varies greatly in appearance and 

 flavour, according to the food upon which the animals have 

 been respectively fed. The differences in question seem to be 

 principally due to the fact already mentioned, that a certain 

 amount of the food-fat becomes absorbed and deposited in the 

 tissues while undergoing little or no change. The experiments 

 alluded to in the following extract from Henry's Feeds and 

 Feeding, confirm this view : " Lebedeff and Munk fed a dog 

 mutton suet, and later rape oil, for a long time and in large 

 quantities, and found that the fat deposited in the body was 

 more like mutton suet or rape oil in its chemical properties 

 than normal dog fat. Munk showed that neutral fat may 

 be formed in the animal body resulting from the feeding 

 of free fatty acids. He fed a starved dog lean meat and 

 a large quantity of fatty acids prepared from mutton suet. 

 The animal, which had shrunk 32 per cent, in weight 

 during nineteen days, was fed 3,200 grams of flesh and 

 2,850 grams of fatty acids in fourteen days, and increased 

 17 per cent, in weight during this period. When killed 



