790 URINE. 



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

 proteoses are also precipitated. 



The reaction with metaphosphoric acid 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 

 quantity 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 l 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. 



Reaction with sulphosalicylic acid. 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 precipitate the uric acid or the resin acids. (Rocn's 2 test.) 



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 

 ordinary cases HELLER'S test is sufficiently delicate. If no reaction is 

 obtained with this test within 2J to 3 minutes, the urine tested contains 

 less than 0.003 per cent of proteid, and is to be considered free from pro- 

 teid in the ordinary sense. 



The use of precipitating reagents presumes that the urine to be investi- 

 gated is perfectly clear, especially in the presence of only very little 

 proteid. The urine must first be filtered. This is not easily done with 

 urine containing bacteria, but a clear urine may be obtained, as suggested 

 by A. JOLLES, by shaking the urine with infusorial earth. Although 

 a little proteid is retained in this procedure and lost, it does not seem to 

 be of any importance (GRUTZNER, SCHWEISSINGER S ). 



The different color reactions cannot be directly used, esspecially in deep-colored 

 urines which contain only little proteid. The common salt of the urine has a 

 disturbing action on MILLON'S reagent. To prove more positively the presence 



^piegler, Wien. klin. Wochenschr., 1892, and Centralbl. f. d. klin. Med., 1893; 

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



2 Pharmaceut. Centralbl., 1889, and Zeitschr. f. anal. Chem., 29. 



'Jolles, Zeitschr. f. anai. Chem., 29; Grutzner, Chem. Centralbl., 1901, 1; 

 Schweissinger, ibid. 



