408 



PHYSIOLOGICAL CHEMISTRY 



sleep induced by potassium bromide or chloral hydrate (Mendel). It 

 is also increased after copious water drinking. A decrease in the 

 excretion of phosphates is at times noted in febrile affections, such as 

 the acute infectious diseases, in pregnancy, in the period during which 

 the fetal bones are forming, and in diseases of the kidneys, because of 

 non-elimination . 



The so-called "phosphaturias" many times represent decreased 

 acidity and not increased phosphate content of the urine. Such con- 

 ditions are, however, significant as indicating a possible tendency to the 

 formation of phosphatic calculi. 



EXPERIMENTS 



i. Formation of "Triple Phosphate." Place some urine in a beaker, render 

 it alkaline with ammonium hydroxide, add a small amount of magnesium sul- 



FIG. 129. "TRIPLE PHOSPHATE." (Ogden.) 



phate solution and allow the beaker to stand in a cool place over night. Crystals 

 of ammonium magnesium phosphate, "triple phosphate," form under these con- 

 ditions. Examine the crystalline sediment under the microscope and compare 

 the forms of the crystals with those shown in Fig. 129, above. 



2. Ammoniacal Fermentation. Stand some urine aside in a beaker for 

 several days. Ammoniacal fermentation will develop and "triple phosphate" 

 crystals will form. 



(a) Examine the sediment under the microscope and compare the crystals with 

 those shown hi Fig. 129. 



(b) Hold a glass rod dipped in concentrated hydrochloric acid near the 

 surface of the urine. Note the fumes of ammonium chloride. 



(c) Insert a strip of red litmus paper in the urine. Permit the paper to dry. 

 Note the gradual restoration of red color, due to volatilization of ammonia 

 (volatile alkali). Run a control test using 0.5 per cent Na 2 CO 3 (fixed alkali). 



3. Detection of Earthy Phosphates. Place 10 c.c. of urine in a test-tube and 

 render it alkaline with ammonium hydroxide. Warm the mixture and note the 

 separation of a precipitate of earthy phosphates. 



