582 



CHEMISTRY OF THE PROTEIDS 



CHAP. 



The melanins are not known to give special reactions ; they do 

 not give the reactions of albuminous substances. The dissociation- 

 products have been investigated by Zdanek and v. Zeynek, v. Zum- 

 busch, Nencki and Sieber, and Berdez. Neither bases nor phenol, 

 leucin, tyrosin, nor cystin could be found. Indol and skatol were 

 isolated by Hoppe-Seyler, 15 and Berdez and Nencki, and in addition 

 also formic and succinic acids and nitrites. These derivatives may, 

 however, be due to impurities. Spiegler's results have already been 

 alluded to. 



The melanins of tumours, when dry, form black, shiny masses; when 



1 J. Berdez and M. Nencki, Arch.f. experiment. Path. u. Pharm. 20. 346 (1885). 



2 K. A. H. Morner, Zeitschr. f. physiol. Chem. 11. 66 (1886); 12. 229 (1887). 



3 H. Hensen and Nolke, Deutsch. Arch.f. klin. Med. 62. 347 (1899). 



4 E. Zdanek and R. v. Zeynek, Zeitschr. f. physiol. Chem. 36. 493 (1902). 



5 M. Miura, Virchow's Archiv, 107- 250 (1887). 



6 J. Brandl and L. Pfeiffer, Zeitschr. f. Biol. 26. 348 (1890). 



7 0. Schmiedeberg, Arch.f. experiment. Path. u. Pharm. 39. 1 (1897). 



8 L. v. Zumbusch, Zeitschr. f. physiol. Chem. 36. 510 (1902). 



9 N. Sieber, Arch. f. exper. Path. u. Pharm. 20. 362 (1885). 



10 M. Nencki and N. Sieber, ibid. 24. 17 (1888). 



11 Abel and Davis, Journ. Exper. Med. 1. 361 (1896). 



12 J. Scherer, LieMg's Ann. 40. 1 (1841). 



13 H. Landolt, Zeitschr. f. physiol. Chem. 28. 192 (1899) ; here the older literature. 



14 H. Wolff, Hofmeisters Beitr. 5. 476 (1904). 



15 F. Hoppe-Seyler, ibid. 15. 179 (1891). 



