96 



PHYSIOLOGY 



CHAP. 



The total energy value of the diets tried by Hirschfeld, 

 Kumagawa, and Klemperer was, as Munk remarked, extremely 

 high, far more than is necessary for a person doing a moderate 

 amount of work. It might therefore be supposed that nitrogenous 

 equilibrium on a diet, poor in protein, is only obtained when an 

 excessively large number of calories is supplied at the same time. 

 This view was, however, disproved by Sive"n (1899). 



Sive'n experimented upon himself for several days with iso- 

 dynamic diets, which were gradually made poorer in protein and 

 correspondingly richer in non-nitrogenous substances. From the 

 following table it will be seen that he obtained nitrogenous 

 equilibrium on an extremely small quantity of protein, without 

 increasing excessively the sum total of calories. 



In a successive series of researches (1901), Siven reduced 

 from day to day the quantity of nitrogen introduced from 18 to 

 2*64 grms. The nitrogen discharged in the urine and the faeces 

 was 4*88 grms. on the fourth day, and 4*06 grms. on the seventeenth. 

 After increasing the daily quantity of nitrogen introduced to 4*02 

 grms., he obtained as an average of four days a loss of 4*30 grms. 

 of nitrogen, approaching, it will be seen, nitrogenous equilibrium. 



W. Caspari (1901) could not confirm upon himself the results 

 obtained by Siven, but that this was not an isolated case, as he 

 suspected, is proved by the earlier researches of Hirschfeld, 

 Kumagawa, and Klemperer. 



All these scientifically conducted experiments prove that the 

 adult man can maintain nitrogenous equilibrium on a diet con- 

 taining a much smaller quantity of protein than that usually 

 regarded as the average, and this he can do without being obliged 

 to add an excessive quantity of heat-producing substances of non- 

 nitrogenous origin in order to raise the total energy value of the diet 

 above the normal. Why have these facts not been taken into account 

 in the determination of the average diet best suited to the adult man 

 who does a moderate amount of muscular and nervous work ? 



