762 URINE. 



acid (30-per cent) saturated with sodium acetate, 2 drops of pure phenylhydrazine 

 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 beau- 

 tifully 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 reaction. SALKOWSKI * 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 HIRSCHL, 

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

 long time (one hour). KISTERMANN 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 HAM- 

 MARSTEN'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 cc.). Too great a delicacy of 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 dextrose 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 levo rotatory, may 

 contain 0.2 per cent sugar 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 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 of the same may be prepared according to BAUMANN'S msthod. 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 tho 

 odor of benzoyl chloride has disappeared. After standing sufficiently long the 

 ester is collected, finely divided, and saponified with an alcoholic solution of sodium 



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

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



2 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 Pfluger's Arch., 91. 



