490 PHYSIOLOGY. , 



anabolism of nitrogen. On the other hand, should the egesta contain 

 more nitrogen than the ingesta, then there has been a catabolism of 

 proteid. Should the income and the output be equal, it is concluded 

 that there is a state of nitrogenous equilibrium. 



The carbon contained in the foods and organized tissues, and 

 which is destroyed by catabolic phenomena, is eliminated by the skin 

 and lungs under the form of C0 2 , by the urine and stools under the 

 form of carbonated organic compounds. From the comparisons of 

 the ingesta and egesta it is ascertained whether there is carbon 

 anabolism, catabolism or equilibrium. 



Proteids, fats and carbohydrates all contain carbon; so that 

 if there be a gain or loss of carbon it may be from the proteids, fats 

 and carbohydrates. To arrive at some solution, it becomes necessary 

 to calculate the quantity of nitrogen eliminated. Every hundred parts 

 of proteid contain 53.6 parts of carbon and 16 parts of nitrogen. If 

 it be known how much proteid has been destroyed nothing is easier 

 than to calculate the quantity of carbon which belongs to it. The 

 remaining carbon that is eliminated must belong to the fats and 

 carbohydrates. 



All of the carbohydrates ingested, except those stored up as 

 glycogen, are burned up in the metabolism of the tissues and their 

 carbon found in the excreta. Hence, by calculating the quantity of 

 carbon which is found in the ingested carbohydrates, one finds what 

 quantity of carbon eliminated belongs to the decomposition of the 

 carbohydrates. If there be an excess of carbon it must come from the 

 fats, since the latter contain, as a mean, 76.5 per cent, of carbon. By 

 multiplying the surplus of carbon by 1.3, there is found the quantity 

 of fat which is gained or lost. 



By nitrogen equilibrium we mean the condition of man when the 

 nitrogen of the egesta is equal to the nitrogen of the ingesta, and this 

 is the normal state of man when properly nourished. If the nitrogen 

 of the ingesta is increased, or even in excess, it is not deposited in the 

 tissues, but after a short time is excreted, the man eating more and 

 excreting more. 



By carbon equilibrium is meant a condition in man where the 

 total carbon of the excreta is equal to the carbon taken in in the 

 ingesta. 



Nitrogen Equilibrium. 



The quantity of proteid food to preserve nitrogenous equilibrium 

 varies with the state of the body; a thin man needs less than a 

 muscular and well-nourished one, 



