I02 THE JOURNAL. OF PHARMACOLOGY. 



The quantity of phosphoric acid excreted under normal conditions de- 

 pends upon the quantity taken in with the food. (During periods of star- 

 ovatin the quantity eliminated is at its minimum.) Furthermore, upon 

 variations of body temperature, and upon the quantity of earthy bases, and 

 salts of alkali metals ingested. Pathologically the quantity of phosphoric 

 acid excreted is diminished in the case of most acute febrile diseases, in 

 case of certain nervous disorders, renal diseases, rhachitis, gout, and 

 chronic rheumatism. It may be increased in diabetes mellitis and menin- 

 gitis. 



Phosphates when eliminated in much increased quantity may give rise 

 to turbid urine, in which case the condition is described as phosphaturia. 

 Sometimes urine of this kind is clear when voided, but becomes turbid 

 after standing a few hours. The reaction of such urine is often alkaline, 

 or at most only slightly acid, or neutral. The sediment which appears is 

 composed chiefly of ammonio-magnesium phosphate (Triple phosphate). 

 The cause of this phenomenon is ascribed to a lack of acidity in the blood, 

 or to certain nervous disorders which affect the .secretory functions of the 

 kidneys. Phosphoric acid forms three kinds of salts, primary, secondary 

 and tertiary. Phosphates of the alkalies are all soluble in water. The pri- 

 mary salts (X H2PO4) impart an acid reaction, the secondary (X 2HPO4) 

 and the tertiary (X 3PO4) an alkaline reaction to the liquid. Of the phos- 

 phates of the alkali earths only the primary salts (X(P04H2)2) are solu- 

 ble in water, imparting an acid reaction. The secondary (X HPO4) and 

 the tertiary salts (X 3(P04)2) are difficultly or not at all soluble in water. 

 The solubility of the latter salts in urine is dependent upon the presence 

 of other salts, such as the primary alkali phosphates and sodium chloride. 

 If, therefore, urine becomes alkaline in reaction, spontaneously, or is ren- 

 dered so by the addition of alkalies, phosphate of calcium, phosphate of 

 magnesium, and ammonio-magnesium phosphate will separate out. Phos- 

 phates are precipitated by the following ; 



A. Silver nitrate in neutral solution. 



B. Magnesia mixture. 



C. Uranium salts in acetic acid solution. 



D. Ammonia molybdate in nitric acid solution. 

 K. Calcium and Barium chlorides. 



If a sample of urine is treated with solution of soda or potassa or am- 

 monia water, earthly phosphates will be precipitated, the alkali phos- 

 phates remaining in solution. The presence of the latter may then be 

 established, after removing the precipitate of earthy phosphates, by the 

 addition of magnesia mixture which will cause a white precipitate to form. 

 Or the filtrate, after first acidulating with acetic acid, may be treated with 

 solution of uranium acetate or nitrate, which will cause a yellow precipi- 

 tate to form. 



