418 RETROGRESSIVE CHANGES 



in 1897 g-ave us the first ^ood idea of the composition of amyloid sub- 

 stance through his amplification of Oddi's®^ observation that amyloid 

 organs contain chondroitin-sulphuric acid, finding that amyloid is a 

 compound of protein with this acid, similar to nucleoprotein, which 

 is a compound of nucleic acid and protein. This work has received 

 general acceptance, although a later paper by Hanssen ®^ reports a 

 study of amyloid material isolated in pure condition from sago spleens 

 by mechanical means, which contained no chondroitin-sulphuric acid, 

 although the amyloid organs taken i)i toto do contain an excess of sul- 

 phur as sulphate. This important contradiction to prevailing ideas 

 has not, so far as I can find, been subjected to investigation by others, 

 with the exception of a casual remark by Mayeda ^^ that a prepara- 

 tion of amyloid which he had made did not yield sulphuric acid. 



Chondroitin-sulphuric acid, which has been studied especially hy jMorner and 

 hy Sclimicdeborg,8" has tlie formula C\sH^^NS0,7, accordin<T to tlie latter, and 

 yields on cleavage chondroitin and sulphuric acid, as follows: 



C,sHj,NSOiT + H,0 = CigHjjNO,, + USO, 



Kondo,88 however, gives it an empirical formula of Ci^HojNSOia, there being ap- 

 parently two equivalents of tlie base for each SO4 group. Levene and La Forge «' 

 have demonstrated that cliondroitin-sulphuric acid consists of sulphuric acid, 

 acetic acid, cliondrosamine wliich is an isomer of glucosamine, and glucuronic acid. 

 It unites with histones and forms a precipitates^ Chondroitin is a gummy sub- 

 stance which in turn may be split into acetic acid and a reducing substance, 

 chondrosin. Chondroitin-sulphuric acid is the characteristic component of car- 

 tilage, but it is also found in mucin (Levene), and in the walls of the aorta and 

 other elastic structures (Krawkow). It has also been found in a uterine fibroma 

 and in bone tissue by Krawkow, but could not be found in the parenchymatous 

 organs, normal and pathological, or in chitinous structures. Morner has also 

 found it in a chondroma. 



Chemistry of Amyloid. — Krawkow separated amyloid from nu- 

 cl('oi)rotein, to which it is most closely related, by dissolving both sub- 

 stances from the minced amyloid organs with ammonia, precipitating 

 with acid, and then taking up the amyloid with Ba(0H)2 solution, in 

 which the nucleoprotein does not dissolve. Amyloid thus isolated is 

 a nearly white powder, which is easily soluble in alkalies, but slightly 

 in acids, and is very resistant to pepsin digestion. The elementary 

 composition was found by Krawkow to be approximately as follows : 



C = 40-50% ; H = 6.65-7% ; N = 13.8-14% ; S = 2.65-2.!)% ; P in traces only. 



Quite similar analytic results have been obtained by Neuberg,"*^ 

 who coi-i'oboi'ated Krawkow 's finding of a body of apparently similar 



Si Ibid., 1894 (.'?.3), .377. 



sf. Biochem. Zeit., 1008 (13), 1S5. 



80 Zeit. phvsiol. Chem., 1000 (58), 475. 



87 Morner." Skand. Arch. Divsiol., 1880 (1). 210; Zeit. phvsiol. Ciiem., 1805 

 (20), 357, and 1807 (23), 311; Schniiedeberg, Arcli. exp. rath. u. rharm.. 1801 

 (28), 358. See also Levene and La Forge, Jour. Biol. Chem., 1013 (15), 60 and 

 155; 1014 (18), 123. 



88 Biochem. Zeit., 1010 (26), 116. 



89 Pons, Arch, internat. phvsiol., 1000 (8), 303. 

 00 Verb. Deut. Path. Gesell.", 1004 (7), 19. 



