EXAMINATION OF NORMAL AND ABNORMAL URINE. 467 



a few drops of solution of potassium ferrocyanide. In the presence of 

 even traces of albumin a turbidity is caused. This test is extremely 

 delicate, especially when modified so as to allow a few c.c. of diluted 

 acetic acid, to which a few drops of potassium ferrocyanide solution 

 had been added, to flow down the side of the test-tube containing the 

 urine. A decided turbidity at the point of contact of the two liquids 

 shows albumin. 



FIG. 43. 



Nitric acid test for urine. 



In case the addition of acetic acid to the cold urine should cause a 

 turbidity (which may be due to mucin) it must be filtered before add- 

 ing the potassium ferrocyanide. 



e. Metaphosphorie acid (glacial phosphoric acid) or trichlor-acetic 

 acid may be used for the detection of albumin by dropping a fragment 

 of either substance into a few c.c. of urine contained in a test-tube. 

 As the acids dissolve, a cloudy ring forms in the presence of albumin, 

 which is not dissolved on warming. 



/. Tanret's test is made by means of a solution containing of potassium iodide 

 3 32 grammes, mercuric chloride 1.35 grammes, acetic acid 20 c.c. in a sufficient 

 amount of water to make 100 c.c. For Millard's test is required a solution made 

 by mixing 2 parts of carbolic acid with 7 parts of glacial acetic acid and 22 

 parts of potassium hydroxide solution. Both solutions give on heating pre- 

 cipitates with albumin, even when present in very small quantity. 



In the above methods the manipulations and precautions are min- 

 utely described, in order to detect small quantities or even traces of 

 albumin. When albumin is abundantly present, there is no difficulty 



