CARTILAGE. 4i:> 



Cartilage. 



The cartilages are invested with a peculiar membrane, the 

 perichondrium ; they are not so hard as bone, but are more 

 elastic and supple. They are usually divided into two classes, 

 the true and the fibrous cartilages. In addition to their re- 

 spective microscopic appearances, they present well-marked che- 

 mical differences. The true cartilages dissolve almost entirely 

 in water, and yield chondrin (see Introduction, p. 25). If, 

 however, the boiling is interrupted before the solution is per- 

 fectly effected, it will be found that the cells have remained 

 almost unchanged, and that only the basic substance has been 

 dissolved. Even when true cartilage is perfectly dissolved the 

 solution is somewhat turbid, owing, probably, to a partial change 

 in the cells. Fibrous cartilage, in which the cells form the 

 preponderating mass when continuously boiled for forty-eight 

 hours, yields only a small quantity of extract, which exhibits 

 all the ordinary reactions of chondrin, but does not gelatinize. 

 The inorganic constituents of cartilage form only a small portion 

 of their mass ; Fromherz and Gugert 1 found in the costal car- 

 tilage of a man aged 20 years, 3'402g of fixed salts, associated 

 in the following proportions : 



Carbonate of soda . .35-1 



Sulphate of soda . . 24-2 



Chloride of sodium . . 8-2 



Phosphate of soda . . 0-9 



Sulphate of potash . . 1-2 



Carbonate of lime . . 18-3 



Phosphate of lime . . 4'1 



Phosphate of magnesia . . 6'9 



Peroxide of iron and loss . 0'9 



In the corresponding cartilage of a woman aged 63 years, 

 the same salts were observed, but to a smaller amount : there 

 was also a larger amount of phosphate than of carbonate of lime. 



[The following analyses of cartilage are extracted from Von 

 Bibra's work: 



1 Schweiger's Journal, vol. 50, p. 187. 



