SUGAR IN URINE. 807 



added, and the mixture boiled in a test-tube until it measures 3 cc. After quickly 

 cooling warm again and then allow it to cool slowly. After 5-10 minutes beautifully 

 formed crystals are obtained even in the presence of only 0.02 per cent sugar. 

 According to the experience of HAMMARSTEN this modification, even in the presence 

 of 0.1 per cent sugar in concentrated urines, does not always give a positive reac- 

 tion. SALKOWSKI x has suggested an even more simple method. 



The value of the phenylhydrazine test has been considerably debated, 

 and the objection has been made that glucuronic acids also give a similar 

 precipitate. A confounding with glucuronic acid is, according to HIBSCHL, 

 not to be apprehended when the test is heated in the water-bath for a 

 long time (one hour). KTSTERMANN found this precaution insufficient, 

 and Roos states that the phenylhydrazine test always gives a positive 

 result with human urine, which coincides with E. HOLMGREN'S 2 and 

 HAMMERSTEN'S experience. This test only shows a non-physiological 

 quantity of sugar when a rather abundant crystallization is obtained from 

 a small quantity of urine (about 5-10 cc.) Too great a delicacy of this 

 test is not to be recommended. 



RUBNER'S test is performed as follows: The urine is precipitated with an excess 

 of a concentrated lead-acetate solution and the filtrate carefully treated with 

 enough ammonia to produce a flocculent precipitate. It is then heated to boiling, 

 when the precipitate becomes flesh-colored or pink in the presence of sugar. 



Polarization. This test is of great value, especially as in many cases 

 it quickly differentiates between glucose and other reducing, sometimes 

 levogyrate, substances, such as the conjugated glucuronic acids. In 

 the presence of only very little sugar the value of this test depends on 

 the delicacy of the instrument and the dexterity of the observer. As a 

 urine which shows no rotation or is actually faintly levorotatory, may 

 contain 0.2 per cent glucose or perhaps even more, this test must be 

 combined with the fermentation test if we are seeking very small amounts 

 of sugar. The sugar in these cases can be detected only by the use of a 

 very accurate and delicate instrument. This method is in many cases 

 not serviceable for the physician. If the urine is to be clarified and 

 partly decolorized by precipitation with lead acetate, it must be done in 

 acid solution with acetic acid. 3 



In the isolation of sugar and carbohydrates from the urine the benzoic-acid 

 esters may be prepared according to BAUMANN'S method. The urine is made 

 alkaline with caustic soda to precipitate the earthy phosphates, the filtrate treated 

 with 10 cc. of benzoyl chloride and 120 cc. of 10 per cent caustic soda solution 

 for every 100 cc. of the filtrate (REINBOLD 4 ), and shaken until the odor of benzoyl 



1 Neumann, Arch. f. (Anat. u.) Physiol., 1899, Suppl. See also Margulies, Berlin, 

 klin. Wochenschr., 1900; Salkowski, Arbeiter aus dem pathol. Inst., Berlin, 1906. 



* Hirschl, Zeitschr. f. physiol. Chem., 14; Kistermann, Deutsch. Arch. f. klin. 

 Med., 50; Roos, 1. c.; Holmgren, Maly's Jahresber., 27. 



3 See Grossmann, Bioch. Zeitschr., 1. 



4 Pfliiger's Arch., 91. 



