60 NORMAL HISTOLOGY. 



of a great variety of substances, and even by slight 

 exposure to the air. The most common change 

 which is noticed in them is a rapid shrinkage, such 

 as occurs when cartilage is exposed to the air or 

 treated with strong salt solutions, or any substance 

 which extracts water from the tissues. Under 

 these circumstances the cell becomes more coarsely 

 granular, it shrinks away from the capsule at certain 

 points, giving the edge of the cell a festooned ap- 

 pearance ; sometimes large, clear spheroidal spaces, 

 called vacuoles, appear in the cell-body, and finally 

 the cell shrinks to a shapeless mass in the centre or 

 at one side of the cavity, or retains its connection 

 with the capsule by one or more narrow irregular 

 projections from the shrunken mass. 



The basement or intercellular substance is not 

 the same in all cartilages, and, according to the 

 differences in its nature, cartilage is divided into 

 hyaline cartilage , fibre cartilage, fibro-elastic cartilage. 



In hyaline cartilage the intercellular substance is 

 homogeneous and transparent in thin layers, some- 

 what opalescent in thicker masses ; it is of firm 

 consistence, and contains at tolerably regular inter- 

 vals variously shaped cavities in which the cells 

 lie, exactly filling them. The layer of basement 

 substance which immediately surrounds the cells 

 possesses slightly different refractive power, and it 

 is this layer which constitutes the capsule above 

 mentioned. 



