SEC. 1. COMPOSITION OF URINE. 



The healthy urine of man is a clear yellowish slightly fluorescent 

 fluid, of a peculiar odour, saline taste, and acid reaction, having a 

 mean specific gravity of 1*020, and generally holding in suspension a 

 little mucus. The normal constituents may be arranged in several 

 classes. 



1. Water. 



2. Inorganic salts. These for the most part exist in urine in 

 natural solution, the composition of the ash almost exactly cor- 

 responding with the results of the direct analysis of the fluid ; in 

 this respect urine contrasts forcibly with blood, the ash of which is 

 largely composed of inorganic substances, which previous to the 

 combustion existed in peculiar combination with proteid and other 

 complex bodies. In the ash of urine there is rather more sulphur 

 than corresponds to the sulphuric acid directly determined; this 

 indicates the existence in urine of some sulphur-holding complex 

 body. And there are traces of iron, pointing to some similar iron- 

 holding substance. But otherwise, all the substances found in the 

 ash exist as salts in the natural fluid. The most abundant and 

 important is sodium chloride. There are found in smaller quanti- 

 ties, calcium chloride, potassium and sodium sulphates, sodium, 

 calcium and magnesium phosphates, with traces of silicates. 

 Alkaline carbonates are frequently found, and nitrates in small 

 quantity are also said to be sometimes present. 



