732 URINE. 



according to the nature of the food and is higher after a diet rich in carbo- 

 hydrates than after food rich in fat (PREGL, TANGL, LANGSTEIN and 

 STEINITZ, and others l ) . 



It is difficult to give a tabular view of the composition of urine on 

 account of its variation. For certain purposes the following table may be 

 of some value, but it must not be overlooked that the results are not 

 given for 1000 parts of urine, but only approximate figures for the quan- 

 tities of the most important constituents which are eliminated during the 

 course of twenty-four hours in a volume of 1500 cc. of urine. These 

 figures apply only to a diet which corresponds to VOIT'S standard figures, 

 namely 118 grams protein, 56 grams fat, and 500 grams carbodydrate 

 per day, and to a man of average weight. 



Daily quantity of solids = 60 grams. 



Organic constituents = 35 grams. Inorganic constituents = 25 grams. 



Urea 30.0 grams. Sodium chloride (NaCl). . . 15.0 grams. 



Uric acid 0.7 " Sulphuric acid (H 2 SO 4 ). ... 2.5 " 



Creatinine 1.5 " Phosphoric acid (P 2 O 5 ) 2.5 " 



Hippuric acid 0.7 Potash (K 2 O) 3.3 



Remaining organic bodies. .2.1 " Ammonia (NH 3 ) 0.7 



Magnesia (MgO) \ n Q 



Lime(CaO) / ' 8 



Remaining inorganic bodies 0.2 



Urine contains on an average 40 p. m. solids. The quantity ot urea is 

 about 20 p. m., and common salt about 10 p. m. 



The physico-chemical methods are being used in urinary analysis 

 even to a greater extent than in the analysis of other animal fluids. A 

 great number of cryoscopic determinations, but fewer conductivity deter- 

 minations, have been made. A constant relation between the values 

 found by physico-chemical methods and the analytical methods has been 

 sought, for example, between the freezing-point depression and the specific 

 gravity of the common salt and others; or attempts have been made to 

 find certain constants in the composition of the urine based upon the 

 results of various methods, and in this way to obtain an explanation as to 

 the mechanism of the excretion of urine in order to apply them for diag- 

 nostic purposes. The results obtained are, as is to be expected, so variable 

 and dependent upon so many conditions which cannot be controlled that 

 definite conclusions must be drawn with the greatest caution. In regard 

 to the value and usefulness of the various constants and relations which 

 are based upon theoretical considerations, the views are unfortunately 

 still too divergent. 



1 Pregl, Pfliiger's Arch., 75, which contains the earlier literature. Tangl, Arch. f. 

 (Anat. u.) Physiol., 1899, Suppl.; Langstein and Steinitz, Centralbl. f. PhysioL, 19. 



