ELIMINATION OF OXYPROTEIC ACIDS 145 



febrile infectious diseases, hepatic affections, the cachexia of 

 cancer and in the later stages of tuberculosis. In any such 

 condition an increased excretion of oxyproteic acids may be 

 told from the increase in the elimination of neutral sulphur, 70 

 which, as previously pointed out (v. Vol. I of this series, pp. 

 548-550, Chemistry of the Tissues), may serve as an index 

 for the former. The degree of complexity of the subject 

 may, however, be inferred from the fact that, according to 

 circumstances, now one, now another fraction of the oxy- 

 proteic acids may predominate in a given case. Thus in 

 tuberculosis a much greater amount of urochromogen is 

 excreted than in cancerous cachexia s. It is a well-known 

 fact that a practical significance is ascribed to the appear- 

 ance and disappearance of the Ehrlich diazo-reaction (now 

 known to be referable to urochromogen) in the matter of 

 prognosis of the course of tuberculosis. 71 



In considering the diazo-reaction 72 it should be observed 

 that besides urochromogen other substances may occur in 

 the urine which yield color reactions with the diazo-bodies, 

 as, according to Clemens, tyrosin (OH.C 6 H 4 .CH 2 .CH(NH 2 ). 

 COOH) and p-oxyphenylpropionic acid (OH.C 6 H 4 .CH 2 .CH 2 . 

 COOH) and p-oxyphenylacetic acid (OH.C 6 H 4 .CH 2 .COOH). 

 Kutscher and Engeland state that even in normal urine after 

 removal of the aromatic oxyacids by ether certain bodies 

 may remain which form red products with diazo-benzol- 

 sulphurous acid when in an alkaline soda solution. This 



N-C 



reaction apparently is peculiar to the imidazol nuclei, C c , 



70 Cf. M. Halpern, Centralbl. f. d. ges. Biol., 11, No. 2547, 1911 ; E. Salkow- 

 ski, Biochem. Zeitschr., 32, 356, 1911; cf. M. Weiss, Munchener med. 

 Wochenschr., 1911, No. 25. 



71 F. Kutscher, Sitzungsber. d. Ges. z. Bef. d. ges. Naturw., Marburg, 4, 83, 

 1908; abst. in Centralbl. f. Physiol., 22, 516, 1908; R. Engeland (Physiol. 

 Instit., Marburg), Miinchener med. Wochenschr., 1908, 1643; M. Weiss and 

 A. Weiss, Wiener klin. Wochenschr., 1912, No. 31. 



"Literature upon the Diazo-reaction in Urine: P. Clemens (Baumler's 

 Clinic, Freiburg), Deutsch. Arch. f. klin. Med., 63, 74, 1899. 

 10 



