322 HERMAN O. MOSENTHAL 



e.c. when taken after a 12 hour fast following a two or three day period 

 of low protein diet, whereas in the same group after they had eaten their 

 customary food for several days, the blood urea nitrogen taken at a cor- 

 responding time (12 hours after the last meal) was considerably higher 

 9.8 to 15.9 mg. per 100 c.c. of blood. The substances, other than the urea, 

 ordinarily determined in clinical tests, creatinin and uric acid, are not 

 as markedly affected by dietetic therapy. How effective a low protein, 

 high starch diet may be in reducing the non-protein nitrogen and urea in 

 the blood may be gathered from Table 5. In this case of chronic nephritis 

 the blood urea N was reduced from 126 mg. per 100 c.c. to 23. This can 

 not be accomplished in every case of like severity; in milder instances 

 it can be brought about very readily. 



TABLE 5 



THE UBEA NITROGEN is REDUCED MARKEDLY IN A CASE OF CHRONIC NEPHRITIS BY MEANS 

 OF A Low PROTEIN HIGH STARCH DIET 



It must be recognized that there are other influences besides the diet 

 and renal efficiency that control the level of the blood urea. There are 

 certain processes that may take place within the body, protein destruc- 

 tion, water loss resulting in inspissation of the blood or dilution of the 

 blood because of fluid retention which may modify the concentration of 

 urea in the blood (Schwartz and McGill, Mosenthal(a), 1914). In the 

 final analysis it must be faulty kidney action that is responsible for the 

 urea retention ; the factors considered above can only be regarded as con- 

 tributory causes. 



In chronic nephritis the blood urea rises slowly until a level of about 

 65 mg. of urea nitrogen per 100 c.c. has been reached ; subsequently it is 

 prone to increase with extreme rapidity (Mosenthal and Lewis). This 

 is due in part to the marked effect produced by even slight diminution in 

 renal function in kidneys that have already been extensively involved and 

 in part due to an increase protein destruction that accompanies extreme 

 oliguria or anuria, and a terminal state. In acute nephritis or the sud- 

 den onset of anuria the blood urea may rise with extreme rapidity. Thus 

 in a dog after nephrectomy (Table 10) the blood urea nitrogen rose to 

 232 in four days. The figure of 351 mg. of urea nitrogen per 100 c.c. of 



