THE SUPPORTING TISSUES. 



105 



them, and in still other cases it lines bony grooves in which 

 tendons of muscles glide. Such cartilage is pre-eminently 



'*HJ 



Fig. 49. WHITE FIBROUS CARTILAGE FROM AN INTERVERTEBRAL DISK. (After Schafer.) 



fitted for positions where strength and rigidity are required. 

 The cartilages shade off insensibly and without any sharp 

 line of demarkation into the connective tissues proper, that 



Fig. 50. TRANSITION FROM CARTILAGE. 

 a, through the intermediate form b, to connective tissue, 6, on the right. 



tissue which pervades all the organs of the body and is the 

 framework of every structure. 



Connective Tissues Proper. 



Of these connective tissues proper, two varieties occur. 

 The elastic is composed of thick, wavy, yellow elastic threads, 

 which frequently branch. This tissue is found in those parts 

 of the body where elasticity is desirable, as for instance, in 

 the walls of the arteries and veins, and is to a large extent 

 the prevailing tissue in the lung. The white fibrous tissue, 

 on the other hand, is composed of bundles of smaller, 

 straighter white threads possessing little or no elasticity. 

 This tissue is especially well exhibited in the tendons and 



