806 URINE. 



alkaline during fermentation (alkaline fermentation), then the test 

 must be discarded. The vessel must be perfectly clean and strongly 

 heated before use. To make sure the urine may be boiled before fer- 

 mentation. 1 



If a good polariscope is at hand it must not be forgotten to control 

 the results of the fermentation by determining the rotation before and 

 after fermentation. The phenylhydrazine test also, in many otherwise 

 doubtful cases, gives good service in testing urines for sugar. 



Phenylhydrazine Test. Can be performed in the following manner: 

 20-25 cc. urine in a test-tube or in a beaker covered with a watch-glass 

 are treated with 1 gram phenylhydrazine hydrochloride and 2 grams 

 sodium acetate, and after solution of the salts it is warmed on the water- 

 bath for three-quarters of an hour. In the presence of sugar even dur- 

 ing the warming, a precipitate occurs, or in the presence of only a little 

 sugar, at least after the gradual cooling, a yellow, crystalline precipitate 

 forms. If the precipitate is very slight, it can be collected to advantage 

 by means of a centrifuge and investigated by aid of the microscope. 

 One finds at least a few phenylglucosazone crystals in the sediment 

 while the appearance of smaller or larger yellow platelets or strongly 

 refractive, brown globules is not indicative of sugar. In the presence 

 of large amounts of sugar in the urine a large quantity of the yellow 

 needles of phenylglucosazone or a mass of them are obtained. 



This reaction is very reliable, and by it the presence of 0.03 per cent 

 sugar can be detected (ROSENFELD, GEYER 2 ). In doubtful cases it is 

 necessary to investigate the nature of the precipitate. For this purpose 

 dissolve a large quantity of the crystals in hot alcohol, treat the filtrate 

 with water, and boil off the alcohol. Still better, the precipitate is 

 dissolved, according to NEUBERG, in some pyridine, and again precipi- 

 tated as crystals by the addition of benzene, ligroin, or ether. If the 

 characteristic yellow crystalline needles, whose melting-point (204- 

 205 C.) may also be determined, are now obtained, then this test is 

 decisive for the presence of sugar. It must not be forgotten that fructose 

 gives the same osazone as glucose, and that a further investigation is 

 necessary in certain cases, and also that the impure crystals of phen- 

 ylglucosazone have a much lower melting-point than the pure ones. 



The following modification by A. NEUMANN is simple, practical, and at the 

 same time sufficiently delicate. 5 cc. of the urine are treated with 2 cc. of acetic 

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



1 On the performance of the fermentation test and certain sources of error, see 

 Salkowski, Berlin, klin. Wochenschr., 1905 (Ewald-Festnummer), and Pfluger, Pfliiger's 

 Arch., 105 and 111. 



2 Rosenfeld, Deutsch. med. Wochenschr., 1888; Geyer, cited from Roos, Zeitschr. 

 f. physiol. Chem., 15. 



