826 URINE. 



for solutions of 1-11 per cent and has a disturbing action upon the deter- 

 mination of sugar by means of the polariscope. It is not precipitated 

 by basic lead acetate or by ammoniacal lead acetate, neither does it 

 ferment. On boiling with water ; especially in the presence of a mineral 

 acid, this acid decomposes into a-crotonic acid, which melts at 71-72 

 C., and water, CHH.CH(OH).CH2.COOH = H 2 O+CH 3 .CH:CH.COOH. 

 It yields acetone on oxidation with a chromic-acid mixture. 



Detection of Q-Oxybutyric Acid in the Urine. If a urine is still levo- 

 gyrate after fermentation with yeast, the presence of oxybutyric acid 

 is probable. A further test may be made, according to KULZ, by evaporat- 

 ing the fermented urine to a syrup and, after the addition of an equal 

 volume of concentrated sulphuric acid, distilling directly without cool- 

 ing, a-crotonic acid is produced, which distills over, and, after collect- 

 ing in a test-tube, crystals which melt at +72 C. separate on cooling. 

 If no crystals are obtained, shake the distillate repeatedly with ether and 

 let this spontaneously evaporate. The crystals which separate out 

 can be purified according to EMBDEN and SCHMITZ by redissolving in ether, 

 evaporating the chief part of the ether and precipitating with petroleum- 

 ether, which removes the volatile fatty acids and benzoic acid. 



The quantitative estimation is done by complete extraction of the 

 /3-oxy butyric acid by ether and determining the specific rotation. The 

 extraction can be done according to MAGNUS-LEVY l or according to 

 BERGELL. 2 Other methods of estimating 0-oxybutyric acid have been 

 suggested by DARMSTADTER, BOEKELMAN and BOUMA. S In regard to 

 the quantitative estimation we refer to EMBDEN and SCHMITZ . 4 



EHRLICH'S 5 Urine Test. Mix 250 cc. of a solution which contains 50 cc. of 

 HC1 and 1 gram of sulphanilic acid in one liter, with 5 cc. of a \ per cent solution 

 of sodium nitrite (which produces very little of the active body, sulphodiazo- 

 benzene). In performing this test treat the urine with an equal volume of this 

 mixture and then supersaturate with ammonia. Normal urine will become 

 yellow or orange after the addition of ammonia (aromatic oxyacids may after a cer- 

 tain time give red azo bodies which color the upper layer of the phosphate sediment) . 

 In pathological urines there sometimes occurs (and this is the characteristic 

 diazo reaction) a primary yellow coloration, with very marked secondary red 

 coloration on the addition of ammonia, and the froth is also tinged with red. 

 The upper layer of the sediment becomes greenish. The body which gives this 

 reaction is unknown, but it especially occurs in the urine of typhoid patients 

 (EHRLICH). Opinions differ in regard to the significance of this reaction. If 

 the urine is made alkaline with sodium carbonate instead of ammonia and treated 



1 See Hoppe-Seyler, Thierfelder's Handbuch, 8. Aufl., 619, and Geelmuyden, Ham- 

 marsten's Festschr., 1906. 



2 Zeitschr. f. physiol. Chem., 33. 



3 Darmstadter, ibid., 37; Boekelman and Bouma, see Maly's Jahresber, 31. 



4 See footnote 5, page 825. 



5 Ehrlich, Zeitschr. f. klin. Med., 5. See also Clemens, Deutsch. Arch. f. klin. 

 Med., 63 (literature). Kutscher and Engeland, footnote 1, page 758. 



