102 



AND NUTRITION 



B. THE TOTAL METABOLISM AFTER INGESTION OF PROTEID 



So far we have confined ourselves to the decomposition of proteid without 

 inquiring how the nonnitrogenous organic foodstuffs behave at the same time. 

 But in order to interpret correctly the phenomena just discussed we must 

 consider also the metabolism of the latter i. e., we must know the total 



1.2 



i.o 



0.8 



o.e 



0.4 



g.N. 



12 4A.M. 12 4P.M. 12 4A.M. 



FIG. 44. The elimination of N in the urine of man, determined every two hours, after Teng- 

 wall. on ordinary diet ; fasting. 



metabolism. As a basis for this discussion we may start with the famous 

 experiments of Pettenkoffer and Voit on equilibrium, which are given in 

 the following tables: 



In the first series of experiments meat only was fed. The nonnitrogenous 

 metabolism is calculated from the carbon excreted (cf. page 90) and is 

 estimated in terms of fat. 



In this and the following tables from Pettenkoffer and Voit, the carbon of proteid is 

 calculated by the ratio, N : C = 1 : 3.28. [This ratio was first determined by Eubner in 

 Voit's laboratory, but is generally attributed to Pfluger. ED.] 



