234 PHYSIOLOGICAL CHEMISTRY. 



The tissues described under the names mucous or gelatinous 

 tissues are characterized more by their physical than their chemical 

 properties and have been but little studied. So much, however, is 

 known, that the mucous or gelatinous tissues contain, at least in 

 certain cases, as in the acalephae, no mucin. 



The nmbilical cord is the most accessible material for the inves- 

 tigation of the chemical constituents of the gelatinous tissues. 

 The mucin occurring therein has been described on page 32. C. 

 TH. MoRtfER has found a mucoid in the vitreous humor which 

 contains 12.20$ nitrogen and 1.19$ sulphur. 



II. Cartilage. 



Cartilaginous tissue consists of cells and of a basic substance 

 originally hyaline, which, however, may become changed in such 

 wise that there appears in it a network of elastic fibres or connec- 

 tive-tissue fibrils. 



Those cells that offer great resistance to the action of alkalies 

 and acids have not been carefully studied. According to former 

 views, the basic substance was considered as consisting of a body 

 analogous to collagen, the so-called cJiondrigen, which under similar 

 conditions passes, like collagen, into a corresponding gelatine called 

 chondrin or cartilage-gelatine. The more recent investigations of 

 MOROCHOWETZ and others, but especially those of C. TH. MORNER, 

 have shown that the basic substance of the cartilage consists of a 

 mixture of collagen with other bodies. 



The tracheal, th^roideal, cricoidal, and arytenoidal cartilages 

 of full-grown cattle contain, according to MORNER, four consti- 

 tuents in the basic substance, namely, chondromucoid, cliondroitic 

 acid, collagen, and albumoid. 



Chondromucoid. This body, according to MORNER, has the 

 composition 047.30, H 6.42, N 12.58, S 2.42, 31.28 per cent. 

 Sulphur is in part loosely combined and may be split off by the 

 action of alkalies, and a part separates as sulphuric acid when 

 boiled with hydrochloric acid. Chondromucoid is decomposed by 

 dilute alkalies and yields alkali albuminate, peptone substance, 

 chondroitic acid, alkali sulphides, and some alkali sulphates. On 



