42 FEEDING ANIMALS. 



The above table is somewhat extended, but as the feeder 

 often desires to know the mineral constituents of his fod- 

 der, he will find this in convenient form for ascertaining 

 the precise character of the mineral substances, and the 

 quantity he is furnishing daily to his stock. 



KESPIBATORY FOOD. But as these preliminary chapters 

 are given to show the parallel between the nitrogenous and 

 mineral elements of plants and animals, we must also ex- 

 plain those non-nitrogenized substances, starch, gum, sugar, 

 etc., which are not found in the animal body, although 

 animals eat large quantities of starch, gum, sugar, and 

 cellulose, and they are necessary for the life of the animal. 

 What becomes of these substances ? Science has proved 

 that they are used to support respiration. Leibig has 

 named starch, gum, sugar, cellulose, etc., composed of car- 

 bon and water only the principles of respiration. Let us 

 illustrate this. If we slake a little burnt lime with water 

 and allow the undissolved lime to settle, then pour off the 

 clear lime water ; and if we then breathe through a glass 

 tube into this clear lime water, the liquid soon becomes 

 milky, and after a little a white powder may be seen falling 

 to the bottom of the glass vessel. This proves that by 

 breathing into lime water we add something to it. Chem- 

 ists know that carbonic acid has a great affinity for lime, 

 with which it forms a white, insoluble powder carbonate 

 of lime. Thus, while breathing, animals are constantly 

 throwing off the carbon in the form of carbonic acid, and 

 this carbon is derived from the starch, etc., of the food. 

 Leibig has calculated that a horse, during twenty-four 

 hours, throws off four to five pounds of carbon. Animals 

 require food containing a large amount of starch to supply 

 this element of respiration. 



This was the accepted theory of scientists to a very 

 recent period. Now, however, as we have explained else- 

 where, it is believed that the oxidation of the carbon of the 



