TEETH. 



[ 754 ] 



TEETH. 



may be displaced by liquids. By removing 

 the inorganic salts from a tooth with dilute 



Fig. 729. 



Ivory-tubes of a fane of a human tooth, a, inner 

 surface of the ivory, with few tubes ; b, their branches ; 

 c, their terminations in loops ; d, granular layer, con- 

 sisting of small ivorv globules at the boundary of the 

 ivory; e, lacunae of bone, one anastomosing with an 

 ivory-tube. Magnified 50 diameters. 



muriatic acid, and macerating the remaining 

 cartilage with acids or caustic alkalies until 

 it forms a pasty mass, the tubes may be 

 isolated from the basis. 



Fig. 730. 



Transverse section of the ivory-tubes, a, closely 

 aggregated ; 6, wider apart. Magnified 450 diameters. 



In sections made from fresh teeth, high 

 powers of the microscope (500 or 1000 

 diameters) being used, it is not difficult to 

 recognize, especially in the centre of the 



Fig. 731. 



Perpendicular section of the apex of a human incisor 

 tooth, a, pulp-cavity ; 6, ivory; c, curved contour lines 

 with interglobular spaces ; d, cement ; e, enamel, with 

 indications of the course of the fibres in various direc- 

 tions ; f, coloured stripes of the enamel. 

 Magnified 7 diameters. 



