320 MICROSCOPIC ANATOMY OF THE TEETH 



the author has been able to detect as many as eight nuclei 

 in an individual cell, as shown in the description of Nasmyth's 

 membrane. 



The most striking point in these preparations is the great 

 abundance of epithelium, and this in a stage when the 

 enamel is completed and the tooth about to erupt ; they 

 also show that Nasmyth's membrane is attached at this 

 stage to the inner margin of the follicle, although in most 

 places its connexion is very slight and it is easily detached. 



FIG. 208. Mass of epithelium at inner margin of follicle. Some 

 portions of last-formed enamel still attached. ( x 150.) 



This point is further considered in describing Nasmyth's 

 membrane. 



The Sheath of Hertwig. Although it was long ago shown 

 that an epithelial investment of the whole tooth is found in 

 mammalian teeth, the real importance and significance of 

 this discovery has scarcely been sufficiently recognized. 



Not only is the enamel laid down by epithelial cells, but 

 the growing dentine, although a mesodermic product, is 

 also under the influence of an epithelial organ, the ' sheath 

 of Hertwig ', and, as will presently be shown, it would appear 

 that the conclusion of Von Brunn that where there is ' no 



