388 PHYSIOLOGICAL CHEMISTRY. 



reverse of the above may be observed even though the urine has a 

 low specific gravity, a pale color, and is poor in solids. 



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 amounts of the most important constituents which 

 are eliminated in the course of 24 hours in a quantity of 1500 c.c. 



Daily amount of solids = 60 grms. 



Organic constituents = 35 grms. 



Urea 30 



Uricacid 0.7 



Creatinin 1.0 



Hippuric acid 0.7 



Remaining organic bodies 2.6 



Inorganic constituents. . = 25 grms. 



Sodium chloride (NaCl). 15.0 



Sulphuric acid (H 2 SO 4 ). 2.5 



Phosphoric acid (P a O).. 2.5 



Potash (K 2 O) 3.3 



Ammonia (NH 8 ) 0.7 



Magnesia (MgO) 0.5 



Lime(CaO) 0.3 



Remaining inorg. bodies 0.2 



Urine contains on an average 40 p. m. solids. The amount of 

 urea is about 20 p. m. and common salt about 10 p. m. 



V. Casual Urinary Constituents. 



The casual appearance in the urine of medicines or of urinary 

 constituents resulting from the introduction of foreign substances 

 into the organism is of practical importance, 'because such constit- 

 uents may interfere in certain urinary investigations and also 

 because thev 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 trans- 

 formations certain substances undergo within the body. As inor- 

 ganic substances generally leave the body unchanged, they are of 

 very little interest from this standpoint, but the changes which 

 certain organic substances undergo may be studied by this means 

 so far as these transformations are shown by the urine. 



The bodies belonging to the fatty series, though not without 

 exceptions, fall mostly into a combustion leading towards the end- 



