en. vii STRUCTURK OK TIIK SUPPORTING TlSSfl-'S 



55 



granules, some of which arc often globules of fat. The solid 

 substance of the cartilage in which the cells lie, the matrix as 

 it is railed, shows no structure, but is a little different in nature 

 close round each cell from what it is farther ofF. The living 

 cells continue to live for some time after the cartilage is 

 taken from the animal, but when they die often shrink 

 a way from the matrix, 

 so that it is clearly 

 seen that they lie in 

 cavities in the solid 

 matrix. The cells 

 are often in pairs, 

 and in that case 

 each is somewhat 

 triangular or half- 

 moon shaped ; this 

 at once suggests 

 that they have been 

 ' formed by the divi- 

 sion of one cell. This 



Fic 22> _ Hyalinc cartihBe A , hin scclion highly 



magnified. 



in, matrix : a, group of two cartilage cells ; />, a group 

 IS actually the Case. of four cells ; <:, a cell; , nucleus. 



In the growth of the 



cartilage each cell divides into two cells, and the two new 

 cells as they grow themselves, become more and more 

 separated from each other by the formation of matrix between 

 them. These new cells will later on divide in a similar way, 

 so that a group of four, eight, or more cells which have all 

 sprung from one cell may be seen. 



Varieties of Cartilage. The matrix instead of being 

 clear and semi-transparent, hyaline as it is called, is sometimes 

 fibrous, and of this there are two varieties. So that there arc 

 three kinds of cartilage : 



1. Hyaline cartilage. 



2. Pibro - cartilage. In the matrix are masses of fine 



wavy parallel fibres. 



3. Elastic cartilage. - In the matrix is a close network 



of branched fibres, which make the cartilage especially 

 elastic. It is yellow in colour. 



Cartilage occurs in the following parts of the body of an 

 adult : 



