430 EXCRETION 



albuminuria, is of considerable clinical importance. The following are the 

 standard tests which present no special difficulty except when traces only 

 are present. 



Heat Coagulation. Take a half test-tube of urine, boil, and add a drop 

 of dilute acetic acid. A white coagulum indicates the presence of albumin. 

 A faint cloudy appearance indicates traces. 



Nitric Acid Test. To 5 c.c. of strong nitric acid in a conical test-tube 

 add 10 or 15 c.c. of urine, pouring it gently down the inclined side of the glass. 

 Allow the glass to stand for a few minutes, when a white coagulum appears 

 just above the line of contact of the acid with the urine. This test, known 

 as Heller's test, will usually indicate the presence of traces of albumin. 



Picric Acid Test. Add picric acid to a sample of urine. A whitish 

 precipitate of albumin will appear at the line of contact, as in the preceding 

 test. 



Citric acid two parts and picric acid one part, when boiled with urine 

 will coagulate minute traces of the proteid. 



17. Detection of Sugar in the Urine. Trommels Test. The pres- 

 ence of sugar in the urine can usually be detected by Trommer's test, 

 which depends upon the reduction of copper sulphate in the presence of 

 strong alkali. Boil fresh Fehling's solution and add to it a few drops of 

 urine. When sugar is present a reddish-yellow precipitate of copper oxide 

 comes out. The test should be set away for a few minutes when, if only 

 traces of the reduction are present, a reddish-brown stain will appear on 

 the bottom of the test-tube. Uric acid, if present in excess, may produce 

 a slight precipitation of the copper. 



Fermentation Test. If sugars are present in the urine, they can be de- 

 tected by adding yeast to a fermentation tube filled with urine, the liberation 

 of carbon dioxide indicating the presence of sugar. Cane sugar does not 

 support the growth of yeast, so it forms an exception by this test. 



Phenyl-Hydrazin Test. Phenyl-hydrazin forms crystals of phenyl- 

 glucosazone. To 10 c.c. of urine in a small beaker add o.i of a gram of 

 phenyl-hydrazin hydrochloride and a double quantity of sodium acetate. 

 Heat in the water bath for 20 minutes. Upon cooling a deposit of yellow 

 crystals of phenyl-glucosazone takes place, if glucose is present. 



1 8. Quantitative Determination of Sugar in the Urine. Fill a 10 

 c.c. graduated pipet with freshly prepared Fehling's solution. Take 10 c.c. 

 of urine, measured with a dropping-pipet into a small beaker, and boil. 

 While continuing to boil, add Fehling's solution slowly and cautiously so 

 long as the color is discharged. The amount of Fehling's required to reduce 

 the sugar is a measure of the quantity of reducing sugar present i c.c. of 

 Fehling's being equivalent to 5 milligrams of dextrose. 



For the presence of blood pigments and other abnormal constituents of 

 the urine, the student is referred to special handbooks on the subject. 



