23 



To portions of the urines add a few drops of acetic 

 acid and then a little 5% uranium nitrate solution, — a 

 yellow ppt. of uranium phosphate is formed. 

 The lime, magnesia, iron and other inorganic urinary 

 constituents are comparatively unimportant, and have no spe- 

 cial clinical significance. The tests for them are somewhat 

 complicated and are therefore omitted. 



Demonstration of Carbonates and COo in Urine. Carbon 

 dioxide exists in the urine to some extent in a free state. There 

 are also various carbonates present, especially in the herbivor- 

 ous urine. The amount is very variable and to a great extent is 

 dependent on the kind of food that is eaten ; large quantities of 

 vegetable foods determine an increase both in the combined and 

 in the free carbon dioxide. The carbonates may be broken up 

 .and COo given off by the application of heat or certain acids. 



Heat experiment. Fill a small flask about half full 

 of unfiltered herbivorous urine. Through the perforated 

 stopper of the flask pass some bent glass tubing con- 

 nected with a test tube containing lime water. Heat the 

 urine in the flask, and as it boils the CO, will pass over 

 into the test tube, and calcium carbonate will be formed 

 from the union of the gas with the lime. Repeat the ex- 

 periment with omnivorous urine. 



A simple proof of the presence of carbonates, or 

 CO2 jji the urine is to fill a Doremus Ureometer with 

 25 ce. of the unfiltered urine and introduce 1 cc. of nitric 

 acid. The larger part of the gas (CO,) rises and col- 

 lects in the upper portion of the ureometer. Compare 

 the amounts thus obtained in the urines of horse and 

 man. 



A simpler qualitative test is to add a few drops of 

 nitric or acetic acid to a little unfiltered urine in a test 

 tube. If effervescence occurs it is due to CO2 set free 

 from the carbonates by the acid. '• 



