THE CEMENTUM. 

 Fig. 235. 



373 



Isolated human enamel prisms, after the slight action of hydrochloric acid. Magnified 300 diameters. 



(Kottiker.) 



tissues, and is chemically almost identical with bone. It consists 



of: 



Organic matter (osteine) .... 32.24 



Earthy matter 67.76 



Phosphate of Lime and Fluoride of Calcium 58.73 "| 

 Carbonate of Lime ..... 7.22 



Phosphate of Magnesia 99 [" 



Salts 82 J 



Cartilage (Osteine) 31.31 ) 



Fat . .93 i 32 '^ 



100.00 



Like bone, the cementum consists of lacuna? and pores, and the 

 intervening true osseous tissue. It rarely contains Haversian canals 

 and vessels; though it has peculiar canals analogous to the tubes 

 of the dentine, and other abnormal cavities. 



The osseous tissue may be granular, amorphous, sometimes trans- 

 versely striated, or laminated like bone. The lacunae essentially 

 resemble those of bone; but present great varieties of number, 

 form, and size (^W to even 7 ^ of an inch). The pores are unu- 

 sually numerous and long ( ? ^ of an inch); and often resemble 

 feathers and brushes. (Fig. 232, e.) 



