CHAPTER VII 



STRUCTURE OF THE SUPPORTING TISSUES CAR- 

 TILAGE, CONNECTIVE TISSUE, AND BONE 



OBTAIN specimens of cartilage from the sternal ends of the 

 ribs of a rabbit, a sheep (or, better, still, a lamb), or from the 

 larynx. Cut the thinnest possible slices or sections, as such 

 slices are called, from a piece of cartilage with a razor. Put 

 a very small and thin fragment on a glass slide, add a drop or 

 two of water, and cover it with a thin glass cover slip, taking 

 care that no water gets on the outer side of the cover slip. 

 Examine the thinnest edge with a microscope. 



Cartilage. Cartilage (gristle) is tough but flexible, so that 

 it can be bent by pressure though only slightly ; it is also elastic, 

 that is, it returns to its original form when the pressure is removed. 

 In thin pieces it is semi-transparent and white or bluish-white 

 in colour. When a piece is obtained fresh from the animal it 

 is seen to be covered by a thin fibrous membrane which is 

 reddish because it contains blood-vessels, that is, the fibrous 

 membrane is vascular. This membrane can be readily stripped 

 off, and then the cartilage it covers shows no sign of redness, that 

 is, contains no blood-vessels, is not vascular. To the naked 

 eye it appears to be uniformly of the same substance through- 

 out, but examination with the microscope shows that scattered 

 in the general substance are numerous cells. Each cell 

 is oval or rounded in shape, and contains a round nucleus. 

 The cell, just as a colourless corpuscle does, consists of 

 cell substance, which is largely living material, containing 

 embedded in it, besides the nucleus, numerous minute 



