EXAMINATION OF NORMAL AND ABNORMAL URINE. 391 



from green to blue, violet-red, and yellow or yellowish-green ; 

 while the appearance of the green at the beginning is indispen- 

 sable to prove the presence of bile, the presence of all the other 

 colors is not essential. 



The above test may be made in a somewhat modified form by 

 mixing the urine with a concentrated solution of sodium nitrate, 

 and pouring down the sides of the test-tube concentrated sul- 

 phuric acid, in such a manner as to form two distinct layers; 

 the colors are seen at the point of contact as above. 



If the urine be very dark in color, it should be diluted with 

 water before applying the above tests. 



Ultzmann's test for bile pigment is made by mixing 10 c.c. of 

 urine with 3 or 4 c.c. of potassium hydrate solution (1 in 3 of 

 water), and supersaturating with hydrochloric acid ; the mixture 

 assumes a beautiful emerald-green color. 



Pettenkofefs test for biliary acids is made by dissolving a few 

 grains of cane-sugar in urine contained in a test-tube, and add- 

 ing to it some concentrated sulphuric acid ; the liquid is at first 

 turbid, then becomes clear and almost simultaneously turns 

 yellow, then pale cherry-red, dark carmine-red, and finally 

 a beautiful purple violet. 



. As many substances (other than biliary acids) show a similar 

 reaction, it is often necessary to separate the bile acids by the 

 process described in connection with the consideration of bile 

 itself. 



Urinary deposits (sediments). When urine is allowed to stand 

 for a few hours, a deposit is frequently formed, consisting either 

 of solids which have been suspended in the urine, or of sub- 

 stances which are less soluble in cold urine (and are, therefore, 

 separated on cooling), or which are formed by chemical decom- 

 position. 



When such a deposit is to be examined, a few ounces of the 

 urine should be set aside for several hours in a tall, narrow, 

 cylindrical glass; when the sediment has collected at the bottom, 

 the supernatant urine may be removed by a siphon, or the sedi- 

 ment may be taken out by means of a pipette for examination. 



Sediments are either organized or unorganized. To the first 

 belong: mucus, blood, pus, urinary casts, epithelium, sperma- 

 tozoids, fungi, infusorise, etc. ; to the second belong: uric acid, 



