72 CONNECTIVE TISSUE CAETILAGE BONE 



syncytial network with a mucin-like substance in its vacuoles ; and finally 

 it becomes cellular and closely resembles cartilage.* 7 



The Perichondrium. The perichondrium is a dense fibrous mem- 

 brane which surrounds each individual plate of cartilage. It is continuous 

 with the surrounding connective tissue, and is well supplied with blood- 

 vessels and lymphatics ; it may also contain terminal nerve fibrils. 



The cartilage itself is an absolutely bloodless and nerveless tissue. 

 Neither are lymphatic channels demonstrable within the cartilage matrix. 



\ 



*** -5. -", -- '"^Ss'v ' 'L' '- '.,, 



Y**#"^$ -'':' -. '>:: 



"V3-. ...:(:"':.,; .- ;v--: *J^ -. ; ;... J* 



KKVr 



;. t . 



r 







'-/ 



-" - ..:-. ,; '-:... . 



FIG. 85. NOTOCHORDAL TISSUE. 



A, from pig embryo of 150 mm.; the syncytium contains many mucin-filled spaces. 

 X 800. B, from nucleus pulposus of an adult pig; the three cells shown are greatly 

 vacuolated. X 452. (After L. W. Williams, Amer. Jour. Anat., 8, 3, 1908.) 



After long maceration or artificial digestion the matrix assumes a granu- 

 lar or fibrous appearance, and small channels have been demonstrated 

 within it, which have been said to connect the various lacuna?; but it is 

 evident that these appearances were possibly the result of artificial de- 

 structive processes and could not therefore be considered as evidences of 

 the presence of such structure in living cartilage. 



BONE 



General. Bone is a firm calcareous tissue which is found only in 

 the skeletal system. In the flat bones it forms a double layer of fense 

 osseous tissue between which is a narrow space, bridged across at fre- 

 quent intervals and thus subdivided into a number of compartments, the 



