CARTILAGE. 403 



tissue the matrix here also consists essentially of water and some 

 mucinous substance. Whether or not this is identical with the so- 

 called chondromucoid, which can be obtained from the cartilage of 

 the adult animal, is not known. 



A general idea of the chemical composition of cartilage may be 

 formed from the following analyses, which are taken from His : " 



Costal cartilage Articular cartilage 



(human). from knee-joint (human). 



Water 67.67 per cent. 73,59 per cent. 



Solids 32.33 " " 26.41 " " 



Organic material .... 30.13 " " 24.87 " " 



Mineral salts 2.20 " " 1.54 



Analysis of the mineral salts has given the following results 

 (calculated for 1 00 parts of the mineral ash) : 



Sodium chloride 6.11 per cent. 22.48 per cent. 



Sodium sulphate 44.81 " " 55.17 " " 



Potassium sulphate 26.66 " " 



Sodium phosphate 8.42 " " 7.39 " " 



Calcium phosphate 7.88 \ u (( , u t( 



Magnesium phosphate . . . 4.55 J 



The organic constituents of the cartilaginous matrix are essentially 

 represented by chondroitin-sulphuric acid as such, and its compounds 

 with collagen and albumins. In addition, a small amount of soluble 

 albumins is found, as also a peculiar insoluble albuminous sub- 

 stance, which has been termed albumoid. Handel further found 

 0.2168 per cent, of glycogen, viz., much larger amounts than are 

 obtained from any of the other skeletal parts. 



Chondroitin-sulphuric Acid. This substance is a conjugate 

 sulphate, and, according to Schmiedeberg, has the composition 

 Ci 8 H 27 NO u .SO 3 . On hydrolytic decomposition it yields a hyalin, 

 chondroitin, which in turn gives rise to the formation of chondrosin. 

 The chondrosin, according to Schmiedeberg, can further give rise 

 to glucuronic acid and glucosamin. But this has been disproved 

 (Neubauer, Orgler-Neuberg). Neuberg obtained a substance on 

 hydrolysis of chondrosin, which was shown to be tetra-oxyamino- 

 capronic acid [C 6 H 7 O 2 (OH) 4 (NH 2 )]. This in turn is combined in 

 the chondrosin with a carbohydrate-like substance of unknown 

 composition. 



(1) C 18 H 27 NO U .S0 3 + H 2 = C I8 H 27 NO M + H^O, 



Chondroitin-sulphuric Choudroitin. 



acid. 



(2) C 18 H 27 NO U + 3H 2 = C 12 H 21 NO U + 3CH,.COOH 

 Chondroitin. Chondrosin. Acetic acid. 



(3) C I2 H 21 NO U + H 2 = C 6 H 7 2 (OH) 4 (NH 2 )+z 

 Chondrosin. 



Both chondroitin and chondrosin are monobasic acids. The latter 

 reduces Fehling's solution directly, while in the case of chondroitin 

 this occurs only after the substance has been decomposed. 



Chondroitin-sulphuric acid is an amorphous substance, and is 



