376 



HERMAN O. MOSENTHAL 



cause, an inability of the kidney to eliminate sufficient solids during the 

 daytime as to make the night an interval of comparative rest and in- 

 activity ; second, when edema exists and a period of elimination and poly- 

 uria has set in which persists day and night. The excess of water voided 

 at night occurs partly because there is a residue of solid material to be 

 excreted, partly because the power to concentrate the urine at higher 

 levels has been lost, and in other instances (eliminating edema) because 

 there is an excess of fluid furnished the kidney for excretion. Noc- 

 turnal polyuria usually (except in the patients who are in the process of 

 ridding themselves of edema) means that the patient is taking an amount 

 of food which his kidneys must excrete by an abnormal degree of 

 effort. By changing the diet to one of a lower level of protein (for it 

 is the end-products of protein, as well as the water and salts that are ex- 

 creted in the urine, whereas the substances resulting from the digestion 

 of carbohydrates and fats are excreted through other channels) the noc- 

 turnal polyuria is often set aside. 



Thus in a series of 21 patients (see Table 32) with nocturnal polyuria 

 on either a low or a moderately high protein diet there were 19 whose high 



TABLE 32 



COMPARISON OF NIGHT URINES IN CASES IN WHICH THERE WAS NOCTURNAL POLYURIA 

 (MORE THAN 750 c.c.) ON EITHER A HIGH OR Low PROTEIN DIET. IN EVERY IN- 

 STANCE A GREATER AMOUNT OF SOLIDS is ELIMINATED WITH THE LARGER VOLUME 

 OF NIGHT URINE, THUS INDICATING THAT IT is THE NECESSITY OF EXCRETION OF 

 SOLIDS THAT CAUSES A NYCTURIA 



