8 5 



made out. The lower layer consists of very regular, tall, 

 columnar cells, the enamel cells. These cells are engaged 

 in depositing the enamel, consisting of prisms of a struct- 

 ureless substance. Above the enamel cells are found 2 to 

 3 layers of short columnar or polyhedral cells. Then there 

 is a layer of varying thickness composed of highly meta- 

 morphosed epithelial cells, seen in the form of flattened 

 plates or fibres, or spindle-shaped or star-shaped cells. 

 This layer constitutes the enamel pulp. The outer layer 

 is composed of two or three rows of flattened, irregular 

 cells in connection with the epithelium lining the mouth 

 cavity. 



In the dental papilla the cells of the peripheral part 

 have assumed a very regular arrangement, and are colum- 

 nar in shape. They constitute the layer of odontoblasts, 

 and are engaged in the deposition of dentine. The dentine 

 is quite deeply stained in eosin in this section. In it fine 

 canals can be made out, into which the processes of the 

 odontoblasts extend. The remaining portion of the dental 

 papilla shows the structure of embryonic connective tissue. 

 Make an outline sketch of the section as shown under low 

 power, and of one of the developing teeth as seen under 

 high power. 



