56 



MANUAL OF PIIYSIO1 OUY. 



easily separable. They swell and dissolve in boiling water, 

 yielding gelatine, which forms a jelly on cooling. 



In some parts of the body, however, a different kind of inter- 

 cellular substance is formed, which is highly elastic, does not give 

 gelatine on boiling, and is not affected by weak acids or alkalies. 

 This is spoken of as Yellow elastic tissue. It is sometimes found 

 alone forming an elastic band or ligament, but more commonly 



FIG 27. 



FIG. 28. 



FIG. 27. Coarse (a) and fine (b) yellow elastic fibres after treatment with strong acetic 

 acid. (Cadiat) 



FIG. 28. Elastic membrane from inner coat of aorta, and, below, mesh-work of elastic 

 fibres from a yellow ligament. (Cadiat.) 



mingled with fibrillar tissue to form the common connecting 

 medium which lies under the skin and between the various other 

 textures. 



In Cartilage 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 



