x THE GLYCO-PROTEIDS : CHONDRO-MUCOID 543 



as to the composition of cartilage, as also an accurate description of 

 the chondro-mucoid, we owe to Morner, 1 who showed that cartilage, 

 apart from the cells enclosed in it, consists, firstly, of an albumoid, 

 which forms a trabecular network, and, secondly, of collagen and 

 mucoid, which fill the spaces between the trabeculse (compare with 

 p. 566). 



Chondro-mucoid shows the usual reactions of the mucins and 

 mucoids : it dissolves in alkalies to a neutral, thick fluid, and is 

 precipitated by acids. Most of the salts of the heavy metals cause a 

 precipitate, but the alkaloidal reagents do not ; tannic acid in particular 

 does not precipitate, even in the presence of salts. Chondro-mucoid 

 even prevents the precipitation of other albumins, such as gelatin, by 

 tannic acid, and this explains the older statements as to the non- 

 precipitability of chondrin, which is a mixture of chrondro-mucoid and 

 of gelatine. The colour-reactions are all positive ; ammonium sulphate 

 salts out. The percentage composition 1 of chrondro-mucoid corre- 

 sponds to that of the mucins ; the high sulphur-content, 2*42 per cent, 

 of which 1*8 per cent is due to chondro-sulphuric acid, is specially 

 noteworthy. By the action of acids, and even more readily by that 

 of alkalies, towards which it is very susceptible, it is dissociated, there 

 being formed an albuminate, albumoses, and peptones, a reducing 

 carbohydrate, and chondro-sulphuric acid. Fischer and Boedeker 

 prepared, already in 1861, a nitrogen-containing acid from cartilage; 

 afterwards Krukenberg 2 called this acid "Chondroitsaure," and described 

 it more fully. The acid was first prepared in a pure state by Morner, 

 who recognised it as a paired sulphuric acid, and who accurately 

 described its properties. Subsequently it was investigated by 

 Schmiedeberg 3 and Orgler and Neuberg. 4 The chondroitin-sulphuric 

 acid or, shortly, chondro-sulphuric acid, is a colloidal substance of 

 unknown constitution. If it be boiled for a short time with acids it 

 becomes decomposed into sulphuric acid and a remainder, which con- 

 tains no sulphur, and which Schmiedeberg called " chondroitin." It is 

 therefore a paired or ethereal-sulphuric acid. 



Chondroitin is a gum-like acid which, by further action of acids, 

 is converted into " chondrosin," an aminated polysaccharid. From this 

 latter Orgler and Neuberg prepared a hexosamin- or tetra-oxy-amino- 

 caproic acid, the exact configuration of which is still unknown. They 



1 C. T. Morner, Skandinav. Archivfiir Physiol. 1. 210 (1889). 



2 F. C. W. Krukenberg, Sitzungsber. der Wurzburger phys.-med. Ges. 1883 (reprint) ; 

 F. C. W. Krukenberg, Zeitschr.f. Biolog. 2O. 307 (1884). 



3 0. Schmiedeberg, Archiv f. experiment. Pathol. und Pharmak. 28. 355 (1891). 



4 A. Orgler and C. Neuberg, Zeitschr. f. physiol. Chem. 37. 407 (1903). 



