STATISTICS OF NUTRITION. 681 



given to an animal as is lost during starvation, the destruction of the 

 proteids of the tissues would cease. But since the administration of 

 albumen increases the tissue waste this is not the case, and at least 

 two and a half times as much albumen must be given as the body loses 

 in starvation in order to preserve the balance. If enough of albumen is 

 given to an animal to prevent its drawing on the albuminoids of its tis- 

 sues, then the amount of nitrogen eliminated will just equal the amount 

 contained in the food, and a nitrogenous balance is thus preserved. 



If, now, to such an animal a larger amount of meat is given, the 

 eliminated nitrogen does not at first increase, and a certain amount of 

 the nitrogen remains in the body to increase the albuminoids of the 

 tissues. Soon, however, the nitrogen eliminated increases until finally a 

 nitrogenous balance is again regained. Every increase in the albumen 

 of the food has the same result — first, an increase in the store of pro- 

 teids of the body, and then an increase of urea, until the nitrogen of the 

 latter equals the nitrogen of the food. A maximum is soon, however, 

 reached in which the limit of albumen which can be digested and ab- 

 sorbed is attained. 



A similar state of affairs holds in animals in a condition of nitro- 

 genous balance when the albumen of the food is diminished. At first 

 there is no decrease in the amount of urea eliminated, so the albuminoids 

 of the tissues must have been drawn upon to make up the excess of 

 nitrogen in the urine over that of the food. Then in a few days the 

 elimination of nitrogen becomes reduced, until again a nitrogenous bal- 

 ance is regained. Every further decrease in the ration of albumen has 

 the same effect — first, decrease of the store of tissue-albumen, and then 

 nitrogenous balance. The minimum limit is then reached. When too 

 small an amount of albumen is given in food to balance the tissue waste 

 inanition then commences. 



These facts show that the requisite amount of albumen in the food 

 to prevent excess of tissue waste is dependent on the store of albumen 

 in the bod3', and that the better the body is nourished by previous feed- 

 ing the more food must be given to preserve a nutritive balance. Con- 

 sequently, well-nourished animals require more food, badlj'-nourished 

 animals less food, to preserve an equilibrium. 



The amount of albumen in the food has, also, an influence on the 

 body fat. If a small amount of albumen undergoes destruction, fat 

 must be given up by the body in order to supply the amount of carbon 

 necessary to form CO a . If the body is rich in fat, and in consequence of 

 abundant albuminous food a large amount of albumen undergoes de- 

 struction, the fat decreases ; but if only a little fat is stored up and still 

 a large amount of albumen is given in food, and there is, consequently, 

 a large destruction of albumen, all the nitrogen is eliminated in the urine, 



