254 



FORMATION OF THE ENAMEL. 



The enamel is represented as being deposited in minute 

 'particles of a calcareous, crystalline character, neither very 

 compact, nor firm, but soon becoming solid and strongly 

 adhering to the surface of the ivory ; its fibres being per- 



pendicular to and 

 having a different 

 direction from 

 those of the ivory. 

 We select from 

 Mr. Nasmyth the 

 accompanying 

 figure, which 

 shows all the dif- 

 ferent structures 

 entering into the 

 composition of a 

 tooth, as the blood 

 vessels, pulp, cells 

 of pulp, their con- 

 version into den- 

 3 tine, enamel, and 

 cementum, at a 

 single glance, and 

 which we have 

 introduced here 

 at the close of 

 their description, 

 in order that a 

 proper estimate 

 may be formed of 

 this gentleman's 

 views of the mode 

 in which teeth are 

 formed. 



FIG. 72, 1 1 Blood vessels and capillaries of the pulp. 2 2 Cells in pro- 

 cess of conversion into ivory or dentine. 3 3 Line showing the transition of 

 these cells into the structure of dentine more clearly. 4 4 The dentine. 5 5 

 Enamel. 6 6 Cortical substance or crusta petrosa. 



