In this tissue the intercellular substance secreted by the cells is hard, and forms in the earlier stages of its development cases or cell walls for the cells. These cases subsequently increase in thickness, and become fused together into a homogeneous intercellular substance, where ultimately the areas belonging to the different cells can no longer be distinguished from one another, so that in the adult tissue there is a tough matrix of intercellular substance, in which the cells are scattered, apparently occupying small cavities. These cells preside over the nutrition of the tissue. The intercellular substance, which is quite homogeneous in common hyaline cartilage, is sometimes modified so as to resemble fibrous tissue, sometimes the fibrillar, and sometimes the elastic form being produced. (Figs. 31 and.

White fibro cartilage, showing cells (a) in capsules and fibrillar matrix (b).

Fig. 32. White fibro-cartilage, showing cells (a) in capsules and fibrillar matrix (b). (Cadiat).

Transverse section of a system of Havers, showing Haversian canal in centre.

Fig. 33. Transverse section of a system of Havers, showing Haversian canal in centre, with bone cells arranged around it in lacuna, which are connected by the delicate canaliculi. (Cadiat).