746 URINE. 



crystals, and it does not appear in urine previously diluted. A con- 

 fusion with resinous acids, which also give a whitish ring with this test, 

 is easily prevented, since these acids are soluble on the addition of ether. 

 Stir, add ether, and carefully shake the contents of the test-tube. If 

 the cloudiness is due to resinous acids, the urine gradually becomes clear, 

 and on evaporating the ether a sticky residue of resinous acids is obtained. 

 A liquid which contains true mucin does not give a precipitate with this 

 test, but it gives a more or less^strongly opalescent ring, which disappears 

 on stirring. The liquid does not contain any precipitate after stirring, 

 but is somewhat opalescent. If a faint, not wholly typical reaction is, 

 obtained with HELLER'S test after some time with undiluted urine, while 

 the diluted urine gives a pronounced reaction, the presence is shown of 

 the substance which used to be called mucin or nucleoalbumin. In this 

 case proceed as described below for the detection of nucleoalbumin. 



If the above-mentioned possible errors and the means by which they 

 may be prevented are borne in mind, there is hardly another test for 

 proteid in the urine which is at the same time so easily performed, so 

 delicate, and so positive as HELLER'S. With this test even 0.002 per 

 cent of albumin may be detected without difficulty. Still the student 

 must not be satisfied with this test alone, but should apply at least a 

 second one, such as the heat test. In performing this test the (primary) 

 proteoses are also precipitated. 



The reaction with metaphosphoric acid (see page 98) is very convenient 

 and easily performed. It is not quite so delicate and positive as HELLER'S 

 test. The proteoses are also precipitated by this reagent. 



Reaction with Acetic Acid and Potassium Ferrocyanide. Treat the 

 urine first with acetic acid until it contains about 2 per cent, and then 

 add drop by drop a potassium-ferrocyanide solution (1:20), carefully 

 avoiding an excess. This test is very good, and in the hands of experts 

 it is even more delicate than HELLER'S. In the presence of a very small 

 quantities of proteid it requires more practice and dexterity than HEL- 

 LER'S as the relative quantities of reagent, proteid, and acetic acid influence 

 the result of the test. The quantity of salts in the urine likewise seems 

 to have an influence. This reagent also precipitates proteoses. 



SPIEGLER'S Test. SPIEGLER recommends a solution of 8 parts mercuric 

 chloride, 4 parts tartaric acid, 20 parts glycerin, and 200 parts water as a very 

 delicate reagent for proteid in the urine. A test-tube is half filled with this 

 reagent and the urine is allowed to flow upon its surface drop by drop from a 

 pipette along the wall of the test-tube. In the presence of proteid a white ring is 

 obtained at the point of contact between the two liquids. The delicacy of this 

 test is 1 : 350,000. JOLLES 1 does not consider this reagent suited for urines very 

 poor in chlorine, and for this reason he has changed it as follows: 10 grams mer- 

 curic chloride, 20 grams succinic acid, 10 grams NaCl, and 500 cc. water. 



ROCK'S Test. Treat the urine either with a 20 per cent watery solution of 

 sulphosalicylic acid or a few crystals of the acid. This reagent does not pre- 

 cipitate the uric acid or the resin acids. 2 



As every normal urine contains traces of proteid, it is apparent that 

 very delicate reagents are to be used only with the greatest caution. For 



'Spiegler, Wien. klin. Wochenschr., 1892, and Centralbl. f. d. klin. Med., 1893; 

 Jolles, Zeitschr. f. physiol. Chem., 21. 



2 Phannaceut. Centralbl., 1889, and Zeitschr. f. physiol. Chem., 29. 



