THE CARTILAGINOUS TISSUE. 157 



more or less flattened. Boiling, at first, crisps, but con- 

 tinued, reduces cartilage to jelly. This is said to be 

 true only of the articular cartilages, the others, having lit- 

 tle or no gelatin, are not dissolved. Drying makes this 

 tissue appear of a semi-transparent yellow color, dimin- 

 ishes its bulk, and destroys its elasticity. Cartilage con- 

 tains a great quantity of water, upon which depends its 

 properties of color, flexibility, volume, and elasticity, and 

 which, when impaired or lost, may be recovered by restor- 

 ing the water. Alcohol renders this tissue slightly opaque; 

 acids, concentrated, dissolve it. Chemical analysis makes 

 cartilage to consist of gelatin 44.5, phosphate of lime 0.5, 

 water 55. Maceration and putrefaction are resisted for a 

 longer time by this tissue than any other, except bone. 



The structure of cartilage appears to be homogeneous, 

 presenting, according to M. Beclard, neither " cavities nor 

 canals, nor areolas, nor fibres, nor Iamina3, nor blood ves- 

 sels, nor absorbents, nor nerves;" in a word, they seem to 

 be destitute of every thing like organization. It is never- 

 theless certain there must be a species of circulation an- 

 swering, at least, their mode of existence, as is evident in 

 cases of jaundice, when these parts are deeply tinged with 

 the yellow coloring matter of the bile, and in ossification 

 of this tissue the bony matter is deposited in the centre of 

 the cartilage, which could only be done by the circulation. 

 Mr. Bayle remarks that although the cartilaginous tissue, 

 at first sight, appears homogeneous, yet, on minute exam- 

 ination, small fibres may be discovered," and, when mace- 

 rated for a long time, assumes the appearance of a " cellu- 

 lar net-work." In the embryo cartilages are soft, mucous, 

 and transparent like jelly or glue. In the child they are 

 yet very transparent, soft, and slightly elastic, and in the 

 adult acquire the natural firmness, opacity, and all the 

 properties which especially distinguish them; while later, 

 in old age, they become more yellow, more opaque, less 

 flexible, less elastic, more brittle, dryer, contain less water, 

 and, in proportion, more earthy matter. Cartilage springs 

 from cells like all other tissues. These cells are called 



