xi THE ALBUMINOIDS : AMYLOID 575 



pared by Tschermak, 1 Krawkow, 2 Ludwig, 3 Kostjurin, 4 Modrzejewski, 5 

 Cohn, 6 and Oddi. 7 They removed the other tissue constituents with 

 boiling water, dilute alkalies and pepsin + hydrochloric acid. 



Analyses 8 show a not inconsiderable amount of sulphur. Accord- 

 ing to Lubarsch (Krawkow) its percentage-composition is 



C H N S 



48-86-50-38 6'65-7'02 13-79-14-07 2'65-2'89 25'6-28'0. 



The dissociation -products are enumerated on p. 75, No. 51; the 

 tyrosin-content is therefore fairly high. Amyloid gives all the colour- 

 reactions of albumins, except the lead-sulphide reaction (Tschermak). 

 Neither Kiihne and Rudneff nor Cohn could obtain a carbohydrate, 

 but Oddi found in organs which had undergone the amyloid degenera- 

 tion chondro-sulphuric acid (see p. 542), which, under normal conditions, 

 is absent except in cartilage. Krawkow has further isolated chondro- 

 sulphuric acid from pure amyloid, but it is more firmly bound up in 

 amyloid than in the chondro-mucoid of cartilage, as it could not be 

 liberated by means of pepsin + hydrochloric acid, which converts the 

 amyloid into albumoses. According to Krawkow the staining reaction 

 with methyl-violet depends on chondro-sulphuric acid, but the latter 

 does not cause the staining with iodine. Amyloid should therefore be 

 classed amongst the glyco-proteids, but, as mentioned above, a carbo- 

 hydrate-radical has not yet been demonstrated. Cohn has shown that 

 Krawkow's view that amyloid is related to chitin is wrong. 



Amyloid is quite insoluble in cold water and in salt-solutions ; if 

 boiled for some days with water it is partially dissolved, according to 

 Kiihne and Rudneff; while if heated under pressure it dissolves more 

 readily (Tschermak). Coarse amyloid dissolves only with difficulty in 

 acids (Kiihne and Rudneff, and Krawkow), while finely divided amyloid 

 dissolves in 4 per cent HC1 and also in organic acids (Ludwig and 

 Tschermak). Digestive ferments also only attack very finely divided 

 amyloid readily, while with coarser complexes they have difficulty. 

 Amyloid dissolves readily in alkalies, in baryta water, and in ammonia, 



1 A. Tschermak, Zeitschr. f. physiol. Chem. 2O. 343 (1894). 



2 N. P. Krawkow, Arch. f. exper. Path. u. Pharm. 40. 195 (1897). 



3 E. Ludwig, Wiener med. Jahrbiich. 82. 183 (1886). 



4 S. Kostjurin, ibid. 82. 181 (1886). 



5 E. Modrzejewski, Arch.f. exper. Path. u. Pharm. 1. 426 (1873). 



6 R. Cohn, Zeitschr. /. physiol. Chem. 22. 153 (1896). 



7 Kuggero Oddi, Arch.f. exper. Path. u. Pharm. 33. 376 (1893). 



8 A, Tschermak, Zeitschr. f. physiol. Chem. 20. 343 (1894) ; W. Kiihne and 

 Rudneff, Virchow's Archiv, 33. 66 (1865); C. Schmidt, Liebig's Annalen, 110. 250 

 (1859) ; N. Friedreich and A. Kekule, Virchow's Archiv, 16. 50 (1859). 



