772 URINE. 



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 carbohydrate 

 per day, and to a man of average weight. 



Daily quantity of solids = 55-70 grams. 



Organic constituents 35-45 grams. Inorganic constituents 20-25 grams. 



Urea 25-35.0 grams. Sodium chloride (NaCl) . 10-15.0 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 " 



Ammonia (NH 3 ) 0.7 " 



Magnesia (MgO) \ OR 



Lime (CaO) / ' ' ' ' U ' b 



Urine contains on an average 40 p. m. solids. The quantity of 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 determinations, 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 or the common salt content and others; or 

 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, opinions are unfortunately still too divergent and as the plan and 

 scope of this book do not allow of more detailed description of these facts we 

 must refer to larger works on the urine and diseases of the kidneys. 



V. CASUAL URINARY CONSTITUENTS. 



The casual appearance, in the urine, of medicinal agents or of urinary 

 constituents resulting from the introduction of foreign substances into 

 the organism is of practical importance, because such compounds may 

 interfere in certain urinary investigations; they also afford a good means 

 of determining whether certain substances have been introduced into the 

 organism or not. From this point of view a few of these bodies will be 

 spoken of in a following section (on the pathological urinary constituents). 

 The presence of these foreign bodies, in the urine, is of special interest 

 in those cases in which they serve to elucidate the chemical transformations 

 which certain substances undergo within the organism. As inorganic 

 substances generally leave the body unchanged, 1 they are of very little 



1 In regard to the behavior of certain of these bodies, see Heffter, Die Ausscheidung 

 korperfremden Substanzen im Ham, Ergebnisse d. Physiol., 2, Abt. 1. 



