22 



Phosphates are increased in the urine pathologically in 

 rickets; osteomalacia; osteoporosis; fractures; chronic rheu- 

 matism; diseases of the nervous system; and after great 

 mental strain and worry. Phosphates are decreased in renal 

 diseases and phthisis. 



Physiologically, variations occur chiefly from the character 

 of the food and drink ; in the horse there may be an increase 

 in the urinary phosphates after a large feed of oats, bran, oil- 

 cake, etc. Pathologically, they are increased during the active 

 changes in such bone diseases as spavin, ring-bone, splint, etc. 

 To a small amount of each urine add about half its 

 volume of nitric acid and then add two volumes of a 5% 

 solution of ammonium molybdate and boil. A canary 

 yellow ppt. (crystalline) of ammonium phospho-molyb- 

 date should appear in the omnivorous urine. In the 

 herbivorous urine the presence of so much organic mat- 

 ter renders the test unreliable; although a precipitate 

 may form it is not a typical or characteristic one for 

 phosphates in the urine of the horse, unless the organic 

 matter has been previously removed. 



To each of the urines add half its volume of am- 

 monia and allow it to stand. A precipitate of earthy 

 phosphates is formed, in the urine of man. Filter, add 

 enough nitric acid to give an acid reaction to the urines, 

 and test the filtrates with ammonium molybdate as 

 before. This method separates the earthy from the 

 alkaline phosphates. 



To a portion of the urines add half their volumes 

 of baryta mixture; a copious precipitate. Filter, add 

 nitric acid and test the filtrates with ammonium molyb- 

 date. No ppt. should occur as the baryta mixture pre- 

 cipitates the phosphates as well as the sulphates and 

 carbonates. 



Use a little of the magnesia mixture instead of the 

 baryta mixture. Filter, add a little nitric acid, and test 

 the filtrate with ammonium molybdate. (The magnesia 

 mixture is composed of magnesium sulphate 1 part, 

 ammonium chloride 1 part, ammonia water 1 part, and 

 distilled water 8 parts). 



