122 Indianapolis Biochemical Meeting: Ahstracts [Sept 



3. Two hundred c.c. of nrine are used for analysis, I£ the 

 urine is just barely acid to litmus paper, as normal urine usually is, 

 10 drops of concentrated hydrochloric acid are added. 



If the urine is strongly acid, it may first be made just alkaline 

 by the addition of ammonia drop by drop and then just acid by 

 the addition of concentrated hydrochloric acid drop by drop. As 

 soon as the urine is alkaline, a precipitation of phosphates occurs. 

 As soon as it is made acid, the precipitate of phosphates disappears. 

 One or two drops of acid or ammonia should make the change 

 distinct. If this is not so, either because the urine is turbid or con- 

 tains very little calcium, litmus paper should be used to determine 

 the change. After the urine has been made just barely acid in this 

 way, 10 drops of concentrated hydrochloric acid (specific gravity 

 1.20) are added. 



4. Ten c.c. of 2^ per cent. oxalic acid Solution are next added. 



5. Eight c.c. of 20 per cent. sodium acetate Solution are added. 

 ^. The urine is allowed to stand over night at the room tempera- 



ture. 



7. The calcium Oxalate is filtered and washed free from 

 Chlorides with 0.5 per cent. ammonium Oxalate Solution, until free 

 from Chlorides. 



8. (a) The precipitate may then be dried, incinerated, heated in 

 the blast lamp to constant weight and weighed as CaO. {h) If 

 the precipitate is free from uric acid, the calcium Oxalate may be 

 determined by titration with Standard permanganate Solution instead 

 of by weighing. In this case the ammonium Oxalate from the 

 washing fluid is first removed from the precipitate by washing four 

 times with cold distilled water, filling the filter about two thirds 

 each time and allowing the wash water to drain completely. A hole 

 is then punched in the point of the filter. The calcium Oxalate is 

 washed through into a fiask, 10 c.c. of concentrated sulphuric acid 

 are added and the Oxalate titrated with Standard permanganate 

 Solution at a temperature of from 40° to 60° C. 



