NORMAL COMPOSITION OF URINE 565 



upon to within ten per cent. It nevertheless is of value as serving to 

 show that titratable acidity of the urine, if added to the ammonia, or 

 protective basic output, is a real indication of the presence or absence 

 of acidosis. 



We have seen that the diurnal output of most of the nitrogenous 

 excreta is profoundly influenced by the diet. No normal composition 

 of the urine can therefore be formulated which is not subject to wide 

 fluctuations which are nevertheless within the limits of diversity which 

 may be exhibited by a single normal individual under varying dietary 

 conditions. The following may, however, serve to illustrate the com- 

 position to which the urine of a normal individual subsisting upon a 

 moderate and mixed diet would more or less closely approximate : 



% 



NORMAL COMPOSITION OF URINE. 



(Illustrative Analysis.) 



The following represents a normal twenty-four-hour sample of 

 urine of volume 1500 c.c. and specific gravity 1.010-1.015: 



Constituent. Weight in Approximate 



grams. percentage. 



Water . 1440.0 96.0 



Solids 60.0 4.0 



Urea 35.0 2.33 



Uric acid 0.75 0.05 



Hippuricacid 0.7 C.05 



Oxalic acid 0.015 0.001 



Aromatic oxy-acids 0.06 0.004 



Creatinine 1.0 0.07 



Thiocyanic acid (as KSCN) .... 0.15 0.01 



Indican 0.01 0.001 



Ammonia 0.65 0.04 



Sodium chloride 16.5 1.10 



Phosphoric acid (P 2 O 6 ) 2.5 0.15 



Total sulphuric acid 2.5 0.15 



Silicic acid 0.45 0.03 



Potassium (K 2 O) 2.5 0.15 



Sodium (Na 2 O) 5.0 0.30 



Calcium (CaO) 0.25 0.015 



Magnesium (MgO) 0.30 0.02 



Iron 0.005 0.0004 



REFERENCES. 



THE CARBONACEOUS WASTE-PRODUCTS: 



Pembrey: Jour. Physiol., 1901, 27, p. 66; 1903, 29, p. 195. 



Johansson: Skand. Arch.%. Physiol., 1901, 11, p. 273. 



Hdri: Pfliiger's Arch., 1909, 130, p. 112. 



Warburg: Ergeb d. Physiol., 1914, 14, p. 253. 



Krogh: The Respiratory Exchange in Animals and Man, London, 1916. 



MacLeod: Physiology and Biochemistry in Modern Medicine, St. Louis, 1918. 



Lusk: The Science of Nutrition, Philadelphia, 1919. 

 THE NITROGEINOUS WASTE-PRODUCTS: 



Abel and Muirhead: Arch. f. exp. Path. u. Pharm., 1893, 32, p. 467. 



Hopkins and Hope: Jour. Physiol., 1898-99, 23, p. 271. 



Kossel and Dakin: Zeit. f. physiol. Chem., 1904, 41, p. 321; 1904, 42, p. 181. 



Macleod and Haskins: Jour. Biol. Chem., 1905-6, 1, p. 319. 



