334 



HERMAN 0. MOSENTHAL 



of urea or non-protein nitrogen in the blood; these must be regarded as 

 contributing factors towards changes in the blood; in the last analysis 



TABLE 17 



THE NITROGEN BALANCE FOR THE WHOLE PERIOD is -f 69.1 GM. THE THEORETICAI 

 VALUE OF THE NON-PROTEIN NITROGEN OF THE BLOOD, CALCULATING FROM THE FIRST 

 OBSERVATION OF 29 MG. PER 100 c.c., SHOULD BE 119 MG., PROVIDED THE RETAINED 

 NITROGEN WERE CIRCULATING AS WASTE NITROGEN; THE ACTUAL VALUE is 27 MG. 

 (Mosenthal and Richards) 



of course it is the ability of the kidney to handle the waste products pre- 

 sented to it that is the controlling element in regulating the level of uri- 

 nary excretory products in the circulation (Mosenthal (a), 1914, Mosenthal 

 and Richards). 



By application of biochemical facts recently ascertained, the fate 

 of ingested nitrogen may at least be approximated from blood determina- 

 tions. It is known from the work of Marshall and Davis that urea is 

 evenly distributed throughout the body, except in certain tissues, as the 

 fat, bone, cartilage, teeth, outer layers of the skin, etc., which do not take 

 up urea. Since the greater part of the nitrogen of the food approxi- 

 mately 85 per cent is excreted as urea on a moderately high nitrogenous 

 diet, a substantial increase in the non-protein nitrogen of the blood would 

 be expected if the kidneys did not eliminate this substance sufficiently 

 rapidly to keep pace with its production. It is at the present time not 

 accurately known how the other nitrogenous products destined for uri- 

 nary excretion are distributed in the body. Many of these are evidently 

 stored in the tissues in much greater concentration than they are found in 



