370 HERMAN O. MOSENTHAL 



The above- dietary contains approximately 13.4 gm. of nitrogen, 8.5 

 gm. of salt, 1,760 c.c. of fluid, and a considerable quantity of purin ma- 

 terial in the meat, soup, tea and coffee. 



This method of carrying out the test was found to be rather laborious. 

 Later observations by Schlayer and Beckman, and Mosenthal(c) (1918) 

 showed that, except for certain minor differences, no real discrepancies 

 existed in the results obtained, whether the diet contained so-called diu- 

 retic substances (purins, sodium chlorid, etc.) or not. In fact Mosen- 

 thal (1918) demonstrated that variations in the volume of urine and 

 specific gravity occurred even when no food, but water only was taken, at 

 two hourly intervals, and the urine was collected every two hours. It ap- 

 pears that the kidney in excreting water acts much on the principle of a 

 syphon. It requires a certain amount of fluid to start a diuretic flow, 

 which, when once begun, continues, even after the excess of water elimi- 

 nated is greater than the amount of fluid taken, that has stimulated the 

 kidney to increased activity. It becomes obvious therefore that diet 

 is of minor importance in carrying out the test day for renal function. 

 Under the circumstances it appeared feasible to allow the patient to con- 

 tinue his or her normal diet (with the exception of forbidding food or 

 fluid after supper until the next breakfast) while the test was carried out. 

 This has an additional advantage inasmuch as the individual's reaction 

 to the usual diet and environment can be taken into consideration and any 

 abnormality in renal function may be met by intelligently directed thera- 

 peutic measures. The directions given the patient are these : 



DIRECTIONS FOR "TEST DAY FOR RENAL FUNCTION" 



Eat and drink what you are accustomed to but be sure that neither 

 food nor drink is taken after supper until the test is completed. Note . 

 time and approximate amounts of food and fluid taken at each meal. 



8.00 A.M. Void urine and discard the urine. 



8.00 A.M. Eat breakfast. 



10.00 A.M. Void urine and place all in a labeled bottle. 



12.00 noon Void urine and save as before. 



1.00 P.M. Eat lunch. 



2.00 P.M. Void urine and save as before. 



4.00 P.M. " " " " " " 



7.00 P.M. " " " " " 



7.00 P.M. Eat supper. 



10.00 P.M. Void urine and save as before. 

 All urine voided after 10.00 P.M. until 8.00 A.M. is to be placed in 



a bottle labeled 8.00 A.M. 



8.000 A.M. Void urine and place in the bottle labeled 8.00 A.M. 



