440 PHYSIOLOGICAL CHEMISTRY 



cause the observer to draw wrong conclusions. This ring, if composed 

 of resin acids, will dissolve in alcohol, whereas the albumin ring wiH not 

 dissolve in this solvent. 



Weinberger has shown that a ring closely resembling the albumin 

 ring is often obtained in urines preserved for a considerable time by 

 thymol when subjected to the nitric acid test. The ring is due to the 

 formation of nitrosothymol and possibly nitrothymol. If the thymol 

 is removed from the. urine by extraction with petroleum ether 1 previous 

 to adding nitric acid, the ring does not form. 



An instrument called the albumoscope (horismascope) has been de- 

 vised for use in this test and has met with considerable favor. The 

 method of using the albumoscope is described below. 



Use of the Albumoscope. This instrument is intended to facilitate 

 the making of "ring" tests such as Heller's and Roberts'. In making 

 a test about 5 c.c. of the solution under examination is first intro- 

 duced into the apparatus through the larger arm (see Fig. 135), 

 and the reagent used in the particular test is then introduced through 

 the capillary arm and allowed to flow down underneath the solution 

 under examination. If a reasonable amount of care is taken there is 

 no possibility of mixing the two solutions and a defi- 

 nitely defined white "ring" is easily obtained at the 

 zone of contact. 



2. Nitric Acid and Magnesium Sulphate Ring Test* 

 (Roberts). Place 5 c.c. of Roberts' reagent 2 in a test- 

 tube, incline the tube, and by means of a pipette allow the 

 urine to flow slowly down the side. The liquids should 

 stratify with the formation of a white zone of precipitated 

 albumin at the point of juncture. 



This test is a modification of Heller's ring test 

 and is rather more satisfactory than that test, since 

 the colored rings never form and the consequent 

 FIG. 135. ALBUMO- confusion is avoided. The albumoscope (see above) 

 may also be used in making this test. 



3. Spiegler's Ring Test Place 5. c.c. of Spiegler's reagent 3 in a test-tube, in- 



^ 1 Accomplished readily by gently agitating equal volumes of petroleum ether and the 

 urine under examination for two minutes in a test-tube before applying the test. 



8 Roberts' reagent is composed of i volume of concentrated HNO 3 and 5 volumes of a 

 saturated solution of MgSO 4 . 



3 Spieglers' reagent has the following composition: 



Tartaric acid 2O grams. 



Mercuric chloride 40 grams. 



Sodium chloride 5 o grams! 



Glycerol I00 grams . 



Distilled water , I00 o grams. 



