FOODS IN NUTRITION 177 



CO 2 the other end product. The burning (oxidation) of a 

 carbohydrate outside the body results in the formation of CO 2 

 and H 2 O and the elimination of heat, which last, if properly 

 utilized, can be converted into energy the power to do work. 

 The result of the oxidation of a carbohydrate in the body is the 

 same. Since this class of food is easily handled by the alimen- 

 tary canal, requires little extra O for its destruction, and is very 

 abundantly supplied by the vegetable world, it is the most eco- 

 nomical from digestive, absorptive, respiratory and financial 

 standpoints. Carbohydrates may also be deposited as adipose 

 tissue as will be seen presently. 



3. The fats have the same general office in nutrition as the 

 carbohydrates, viz., the furnishing of energy by their oxidation. 

 They leave the alimentary canal by way of the lacteals, are 

 conveyed by the blood to the tissues and there oxidized with 

 the formation of carbon dioxide and water and the liberation 

 of heat. Though more O is necessary to burn up the fat than 

 the carbohydrate molecule, oxidation of the fat is attended with 

 the liberation of the greater amount of heat i. e., of energy. 

 This would seem to indicate that it would be more economical 

 to eat fats to the exclusion of carbohydrates, since a smaller 

 quantity of the former will supply the requisite amount of energy. 

 This is theoretically true, but considerations of digestion render 

 it not practically so, since fats tax the digestive apparatus much 

 more than carbohydrates. 



The fat deposited in the body the adipose tissue whatever 

 may be its source, is to be looked upon as so much stored-up 

 energy. When the supply of blood is cut off it is the first part 

 of the organism to be consumed. Hence, a fat animal will survive 

 starvation longer than a lean one. 



The individuality, the functional activity, and the properties 

 involved in regeneration of protoplasm are ultimately depend- 

 ent upon its nitrogenous characters. The other constituents are 

 more or less passive. The oxidation of fats and carbohydrates, 



