328 MICROSCOPIC ANATOMY OF THE TEETH 



as the development of the root progresses, until when the 

 apical foramen is completely formed it only just reaches the 

 tip of the root (fig. 217). 



h~ 



FIG. 217. From a specimen in which the root was nearly completed. 

 The epithelial band (h.) only just turns round the root tip and does not 

 enter the pulp. h. Hertwig's sheath. 



FTG. 218. Hertwig's sheath (s.) around root 

 of molar. ( x 50.) 



There is thus every evidence that in man also the epithelial 

 sheath is the determining or moulding organ of the dentine 

 of the root, as claimed for the lower Mammalia by Von Brunn. 



Between the roots of a molar tooth not only is the sheath 

 seen in the neighbourhood of the dentine, but a band of 



