204 MICROSCOPIC ANATOMY OF THE TEETH 



pulp are well described and figured by Dr. Paul in a paper 

 contributed to the Odontological Society in 1899 (23). 



The development of the cells of the dental pulp is further 

 shown in figs. 118 and 119. 



The rounded cells are thus seen to become differentiated 

 into a definite layer of more or less cylindrical cells, the 

 odontoblasts, which surround the pulp and form the mem- 

 brana eboris of Waldeyer. These cells are larger and more 

 fully developed at the coronal portion of the tooth-pulp, and 

 smaller and less conspicuous in the fully formed root. 



FIG. 119. Large irregularly-shaped cells at pulp margin, a. Ameloblasts ; 

 p. pulp; 5. stratum intermedium. (x500.) 



Each odontoblast has a large round or oval nucleus and 

 the cell protoplasm, or cytoplasm, is finely granular. On 

 its dentine aspect it is somewhat flattened, and the dentinal 

 fibril, which is a continuation of its cytoplasm, slightly 

 tapers to its entrance into the dentinal tube (figs. 120 

 and 121). It has been described as not possessing a cell 

 wall, but this is highly improbable, and we must assume 

 tha/b the cell wall is of such extreme tenuity that it is not 

 observable in ordinary preparations. As, however, it has 

 beon shown by Hanazawa (10) that an outer layer to the 

 dentinal fibril is distinctly stainable by hsematoxylin within 



