LECTURE III. 
CARTILAGE. 
Having described the principal fibrous structures, I 
pass on to consider the cellular tissues ; of these, car- 
tilage first claims our attention. This tissue possessing 
great elasticity and flexibility, enters largely into the 
formation of the vertebrate skeleton. It is usually white, 
or of a light grey colour, changing to a yellowish tinge 
after long immersion in spirit. Some animals, the carti- 
laginous fishes, for example, have a skeleton composed 
almost entirely of cartilage. In man, and the higher 
vertehrata, this tissue is employed more sparingly in the 
construction of the adult skeleton ; but in the foetal 
state the form of the skeleton is sketched out in car- 
tilage, which in the process of development is entirely 
converted into bone. 
Cartilage is usually" divided into two kinds, the per- 
