316 MICROSCOPIC ANATOMY OF THE TEETH 



necting bridges with the neighbouring teeth and with the 

 tooth-band become broken up, separated, and partially 

 absorbed ; but in many places these cells do not disappear 

 but proliferate within the connective tissue, and are found 

 in the different forms described by Malassez and Magitot. 

 Malassez described these cell proliferations in connexion 

 with the formation of tumours in the gum and periodontal 

 membrane, and did not fully recognize their true histological 

 and physiological significance ; but he was the first to show 

 that not only in the coronal part of the follicle but in the 

 periodontal membrane surrounding the root of the tooth 

 such epithelial remains are found. 



As will be shown later, the epithelial masses in the 

 periodontal membrane are also derived from the cells of 

 the upper part of the follicle, and although seen in fully 

 formed teeth only as separated groups of cells, are really 

 the remains of a continuous epithelial layer known as the 

 sheath of Hertwig, as was first pointed out by Von Brunn. 



The follicle of the permanent teeth just prior to eruption 

 does not appear to have been hitherto very fully described, 

 chiefly owing to the difficulty of obtaining suitable material 

 for the investigation. As Warwick James says : ' Previous 

 investigations into the histology of these remains have been 

 almost entirely restricted to foetal tissues ; after birth they 

 have been considered chiefly from the standpoint of patho- 

 logy ; ' and he further says : ' The authors ' (referred to 

 above) ' seem to imply that the primary connexion with the 

 epithelial tooth-band is lost, and that a secondary connexion 

 is established between the buds of the epithelium which 

 extend throughout the follicle.' Warwick James considers 

 that ' the proliferation and formation of buds indicates 

 a continuous growth, which continues with variable activity 

 until the eruption of the teeth takes place '. This process 

 certainly appears to occur in the follicle of the permanent 

 teeth, although Legros and Magitot state that ' all end by 

 being absorbed and disappearing ', and other authors, pro- 

 bably referring to this statement, have concluded that 

 nothing remains in the follicle prior to eruption but con- 

 nective tissue and tiny masses of epithelium, the so-called 

 glands of Serres. 



