HO CHEMICAL PHYSIOLOGY. 



it by the contact-method of Heller (d.) The urine is below, 

 and the picric acid on the top. A rapidly-formed deposit at 

 the line of junction of the fluids indicates the presence of a 

 proteid ; the deposit is not dissolved by heat. N.B. Picric 

 acid precipitates all the forms of proteid which occur in 

 urine. It also precipitates mucin, but in this case the 

 deposit usually forms slowly, and after a time. If a person 

 be taking quinine, a haziness is obtained in the urine on 

 adding picric acid, but it disappears on heating. Dr. John- 

 son and Professor Grainger Stewart recommend it as one of 

 the most reliable tests for albumin we possess. 



(g.) Do the biuret reaction, which reacts with albumin, 

 albumose, globulin, and peptone. 



(h.) Metaphosphoric Acid completely precipitates albumin, 

 but it must be freshly prepared, and is difficult to keep. 

 Hence it is not satisfactory. 



(i.) Acidulated Brine, as suggested by Roberts, consisting 

 of a saturated solution of sodic chloride with 5 per cent, of 

 dilute hydrochloric acid (B.P. ), may be used, but it sometimes 

 gives a precipitate with normal urine. Nor is potassio- 

 mercuric iodide satisfactory. In cases of doubt use several 

 tests, especially 2 (6.), (c.), (e.), and (/) 



3. Dry Tests. 



(a.) Use the ferrocyanic pellets introduced by Dr. Pavy. 



(6.) Use the test-papers citric acid and ferrocyanide of 

 potassium introduced by Dr. Oliver. 



4. Globulinuria. Serum-globulin is present in nearly every albu- 

 minous urine. Procure such a urine. It gives the reactions 

 described under 2. 



(a.) Take a tall glass and fill it with water. Drop the 

 urine into the water, and observe if a milkiness is seen in 

 the water, indicating the presence of a globulin. This body 

 is not soluble in pure water, but in weak saline solutions 

 (Lesson L, 6), hence on diluting the urine it is precipitated. 



(6.) Test the urine by the contact method with a saturated 

 solution of magnesic sulphate. 



