ELEMENTS OF PHYSIOLOGY 



yet capable of bending under pressure. This purpose 

 is fulfilled by the elastic tissue called cartilage. A piece 

 obtained fresh from the animal is seen to be covered by a 

 thin fibrous membrane, which is reddish because it contains 

 blood vessels. When this membrane is stripped off, the 



cartilage shows no signs of red- 

 ness, that is, it contains no blood 

 vessels. A thin section of fresh 

 cartilage appears to the unaided 

 eye as uniform as a piece of 

 glass. Under the microscope 

 we see that it is not so, but that 

 scattered in its gen- 

 eral substance are nu- 



FIG. 39. - 



Lining 



cell is rounded and 

 nucleated (Fig. 43). They are often in pairs, 



and in that case adjacent sides are flat ; which 



. . 

 at once suggests that they have ciandCeiis. 



been formed by the division of Resting, f u ii of 



granules, after 

 activity ; lower 



FiG." 40. Six 



one cell. In the growth of car- granules> after 



tilage each cell divides into two cel , ls shrunk 



and contain- 



cells. These new cells later on ing few gran- 

 divide in a similar way, so that 

 a group of four or eight cells that have 

 all sprung from one cell may be seen. The 

 general substance between the cells is de- 

 FIG i TWO P ositecl by the cells and is called the inter- 

 Gastric Glands, cellular substance or the matrix. 

 simple tubular gg. Cartilage may be readily felt in the 



glands such as J J 



these may be nose (in what portion ?), ears, and windpipe. 



ifa It may contain an abundance of the yellow 

 r f th elastic fibers of connective tissue, in which 

 case it is very elastic, as in the ear ; or it 

 may have masses of white fibers, and may be unusually 



