CHAPTER VI. 



THE CONNECTIVE SUBSTANCE GKOUP Continued. 

 CARTILAGE. 



CARTILAGE is divided into three prominent varieties : 1, 

 hyaline ; 2, fibrous ; and 3, elastic or yellow. There is, in 

 addition, a form called ossifying, which will be described in 

 connection with the development of bone. 



Hyaline cartilage is the tissue from which the bones of the 

 skeleton are first made ; it is also found in the articular and 

 costal cartilages, and in the cartilages of the larynx, trachea, 

 and bronchi ; possibly also in some of the nasal cartilages, and 

 in portions of the sternum. All of these tissues consist of a 

 solid material or matrix, in which are capsules which contain 

 the true cartilage corpuscles. 



The character of the intercellular substance determines the 

 particular variety. Thus, hyaline cartilage appears, under the 

 microscope, to be structureless and homogeneous. Fibrous 

 cartilage, on the other hand, has distinct lines of fibrillation 

 extending through it. Elastic cartilage is permeated by net- 

 works of elastic fibrils. 



Hyaline cartilage, though so-called because of its apparent 

 absence of structure, is now known to be less often structure- 

 less than has been supposed, for the researches of Tillmanns 

 have revealed distinct marks of fibrillation in some adult artic- 

 ular and costal cartilages. Soaking the tissue in a 10 per 

 cent, solution of common salt will dissolve out the cement sub- 

 stance and isolate fibrils, though the tissue has previously ap- 

 peared homogeneous. Staining with the picro-carminate of 

 ammonia (Ranvier's formula) will also demonstrate the fibrils. 



Each capsule is probably invested by a delicate membrane, 

 which is thicker in some instances than in others. Extending 



