MAINTENANCE REQUIREMENTS OF MATTER 321 



of protein was given without non-nitrogenous nutrients it proved 

 entirely insufficient for this purpose and about three times as much 

 was required to attain protein maintenance, as the following table 

 shows : 



TABLE 58. EFFECT OF PROTEIN SUPPLY ON PROTEIN KATABOLISM OF 



DOG 



NITROGEN IN 



The results furnish also a striking illustration of the interesting rela- 

 tions between protein supply and protein katabolism which had been 

 demonstrated more than 30 years earlier by the classic experiments 

 of Bischoff and Voit (402), while rendering it evident that the quantity 

 of protein required to produce nitrogen equilibrium when fed alone is 

 very far from representing the minimum demand of the body. 



What is so strikingly true in the total absence of non-nitrog- 

 enous nutrients holds good also in less degree in case of their 

 relative deficiency. If a portion of the non-nitrogenous nu- 

 trients are withdrawn from a mixed ration, the protein katab- 

 olism usually increases. 



408. Effect of surplus of non-nitrogenous nutrients. If, 

 on the contrary, non-nitrogenous nutrients be added to a 

 ration, they tend to diminish the katabolism of protein. 



As regards rations deficient in energy, this is, of course, only 

 the converse of the statement of the preceding paragraph that 



