OXYPROTEIC ACID. 715 



tion with nitric acid. 1 The quantity of neutral sulphur is determined as the 

 difference between the total sulphur and the sulphur of the sulphate and ethereal- 

 sulphuric acids. The readily oxidizable part of the neutral sulphur is determined 

 by oxidation with bromine or potassium chlorate and hydrochloric acid (LEPINE, 

 JEROME 2 ). 



Sulphuretted hydrogen occurs in the urine only under abnormal conditions 

 or as a decomposition product. This compound may be produced from the 

 neutral sulphur of the organic substances of the urine by the action of certain 

 bacteria (FR. MULLER, SALKOWSKI 3 ). Other investigators have given hypo- 

 sulphites as the source of the sulphuretted hydrogen. The occurrence of hypo- 

 sulphites in normal human urine, which is asserted by HEFFTER, is disputed by 

 SALKOWSKI and PRESCH. 4 Hyposulphites occur constantly in cat's urine and, 

 as a rule, also in dog's urine. 



Antoxyproteic acid is a nitrogenous acid containing sulphur which 

 BONDZYNSKI, DOMBROWSKI, and PANEK 5 have isolated from human urine. 

 The composition of the acid was: C 43.21, H 4.91, N 24.4, S 0.61, and 

 O 26.33 per cent. A part of the sulphur can be split off by alkali. This 

 acid is soluble in water, is dextrorotatory, and is only precipitated from 

 concentrated solution by phosphotungstic acid. It does not give the 

 protein color reactions, but gives EHRLICH'S diazo reaction (see below). 

 The salts with the alkalies, barium, calcium, and silver are soluble in 

 water, and of these salts that with barium and, to a still higher degree, 

 the silver salt are soluble with difficulty in alcohol. The free acid and 

 its salts are precipitated by mercuric nitrate and acetate, and by this 

 last reagent even from solutions strongly acidified with acetic acid. Basic 

 lead acetate does not precipitate the pure acid. 



Oxyproteic acid is the name given by BONDZYNSKI and GOTTLIEB 6 

 to a nitrogenous acid containing sulphur and which they prepared from 

 human urine, which has recently been further studied by BONDZYNSKI, 

 DOMBROWSKI and PANEK. This acid contained C 39.62, H 5.64, N 18.08, 

 S 1.12, and O 35.54 per cent, and also contains sulphur which could be 

 split off. On cleavage it yields no tyrosine, nor does it give EHRLICH'S 

 diazo reaction, the xanthoproteic nor the biuret reaction. It gives a 

 faint indication of a MILLON reaction and is not precipitated by phos- 

 photungstic acid, hence it leads to an error in the PnvJGER-BoHLAND's 

 method for estimating urea. The acid soluble in water is precipitated by 

 mercuric nitrate and acetate in neutral solutions, but is not precipitated 

 by basic lead acetate. The salts of this acid are readily soluble in water 

 and more soluble in alcohol than the corresponding salts of antoxy- 

 proteic acid. 



1 See Abderhalden and Funk, Zeitschr. f. physiol. Chem., 58 and 59, which also 

 cites other methods. S3e Folin, Journ. of biol. Chem., 1. 



2 Jerome, Pfluger's Arch., 60. 



3 Fr. Miiller, Berlin, klin. Wochenscbr., 1887; Salkowski, ibid., 1888. 



4 Heffter, Pfluger's Arch., 38; Salkowski, ibid., 39; Presch, Virchow's Arch., 119. 

 13 Zeitschr. f. physiol. Chem., 4(J. 



3 Centralbl. f. d. med. Wissensch., 1897, No. 33. 



