CHAPTER VIII 

 THE TOOTH FOLLICLE AND ITS CONNEXIONS 



IN the present chapter it is proposed to consider the 

 histology of the permanent tooth follicle and the sheath of 

 Hertwig, which is intimately connected with it. 



The Follicle. As shown in Chapter I, the tooth is enclosed 

 in a sac within the bony crypt of the jaw. This sac is com- 

 posed chiefly of connective tissue derived from the outer 

 layer of the mesodermic dentine papilla, and surrounds the 

 whole tooth, including the enamel germ. This extension 

 of the papilla is generally described as an upgrowth from 

 its margins, which is continued until it meets over the con- 

 tained tooth germ, thus completely enclosing it. Whether, 

 however, such upgrowth really -occurs is somewhat doubtful, 

 and Tomes considers it is more probable that the tissue 

 in which the dentine organ is formed has become ' more 

 pronounced ', that the follicle is in fact formed by a con- 

 densation of the connective tissue in the neighbourhood of 

 the tooth germ. 



The bony crypt of the temporary" teeth does not com- 

 pletely surround the tooth, but is open at the top, and is 

 more comparable to a deep groove than a closed crypt. 

 The follicle can be easily separated from the bony crypt 

 and from its attachment to the tissue of the gum, and 

 removed as a separate sac, the mucous membrane of the 

 gum remaining undisturbed, as explained in the chapter 

 on Development, p. 11. 



The dental follicle of the temporary teeth has been very 

 fully described by Magitot (8) in collaboration with Robin 

 and with Legros, (6) and the epithelial elements were first 

 fully investigated by these authors and by Malassez, the latter 

 having specially studied the remnants of the tooth-band in 

 connexion with the occurrence of epithelial tumours in the 

 depth of the jaws. 



Malassez (7) showed that independently of the epithelial 

 process, which develops into the enamel organ, the tooth-band 



