154 MICROSCOPIC ANATOMY OF THE TEETH 



processes do not show any minute fibrillar structure, but 

 certainly such structure appears to be indicated by the 

 photographs (figs. 86 and 87). 



Owing to the wide area of enamel which has only under- 

 gone partial calcification in early enamel germs of Macropus, 

 the prolongations of the Tomes' processes can be traced in 

 many sections all 'across this space to the dentine, and it 

 was no doubt these extensions of the Tomes' processes which 

 were described by Andrews, who was the first to draw atten- 

 tion to this fibrillar foundation of the calcified enamel ( 1 ) . 



FIG. 86. Developing tooth of Macropus. a. Ameloblasts ; t. Tomes' 

 processes spreading out into the forming enamel (e). (x 700.) 



As the ameloblasts are separated from the forming 

 enamel by a membrane, the inner ameloblastic membrane, 

 this must be pierced by the Tomes' processes, which are 

 processes of the ameloblast cell. 



It has been long known that a fenestrated membrane can 

 be detached from the surface of growing enamel by acids, 

 but in some of the author's preparations, where no acids 

 were employed, such a membrane is detached where the 

 enamel is slightly separated from the cells. It is difficult 

 to say whether this fenestrated membrane shown in fig. 88 

 was in contact with the ameloblasts or with the surface of 

 the forming enamel, but it certainly does not require the 

 action of an acid to bring it into view. 



A structure has been described in forming enamel which 



