172 MICROSCOPIC ANATOMY OF THE TEETH 



becomes detached without the action of an acid. According 

 to the author's observations the fibres of the Tomes' pro- 

 cesses spread out in a fan shape at the honeycomb region, 

 portions of the fibrillar process intermingling with those 

 that surround them, and he considers that a rearrangement 

 of the fibres takes place in the honeycomb region, resulting 

 in the formation of the strands which extend in marsupials 

 from the honeycomb throughout the whole width of the 

 forming enamel to the dentine. 



The forming enamel of marsupials and in a less degree 

 human enamel, when teased out in glycerine, shows that 

 the tissue is formed in distinct parallel laminae lying at right 

 angles to the surface. Longitudinal and transverse striae 

 are visible in the laminae, and large radial calcospherites 

 lie upon and between them. A regular deposit of small 

 calcified bodies of uniform size is also seen in the forming 

 enamel prisms. 



The large bodies are concerned in the formation of the 

 interprismatic material, while the smaller ones build up the 

 columns of the prisms. The persistence of these large 

 calcospherites in the interprismatic substance is shown in 

 certain cases of caries and erosion in completed human 

 enamel. Many of these bodies, however, split asunder 

 and break down into small granules. 



The clear bodies which are seen in the ameloblasts have 

 been described by several authors ; they are called by 

 Leon Williams the enamel globules, and he describes them 

 as ' passing down the ameloblasts and emerging from the 

 membrane beneath their inner ends ', the inner ameloblastic 

 membrane before described. On the enamel side of the 

 membrane these bodies, which are more or less regular in 

 size and shape, are arranged along the fibres of the forming 

 enamel and apparently become calcified as fine granules 

 which become fused into the small blocks which form the 

 calcified elements of the finished prisms. These blocks 

 and their constituent granules are seen in figs. 18 and 

 91. He speaks of these bodies being 'compressed into 

 disk-like shapes and sometimes partly or quite melted into 

 one another '. The interprismatic substance appears to 

 be formed independently of the prisms, and is produced 



