270 MANUAL OF HISTOLOGY. 



growths towards the follicle, especially at that portion covered by the gum. 

 These interdigitate with the vascular tufts just referred to. 



We have already considered, in 116, the gelatinous non-vascular tissue 

 enclosed in the cellular tunic of the enamel organ, so that we refer the 

 reader again to what was there remarked. 



The dental germ ( f) appears to be formed of an undeveloped .connective- 

 tissue, of a finely granular dull mass, containing a multitude of roundish 

 nuclei and cells of like shape, or more or less fusiform. It is, moreover, 

 highly vascular, the capillaries being recognisable at a short distance from 

 its surface, forming numerous terminal loops (g, and fig. 258). Numerous 

 nerves are also formed in it subsequently, whose origin calls for more 

 accurate investigation, as also the question as to the occurrence of 

 lymphatic vessels. 



The dental germ is covered by delicate cells arranged in strata, now 

 more or less cylindrical, now of irregular figure (fig. 258, e ; 259). These 

 are the dentine cells or odontoblasts, whose nature and position in the per- 

 fect tooth has already been treated of in 151. They correspond to the 

 osteoblasts of Gegenbaur, which we have seen in the bony tissue ( 147). 

 These cells, taken as a whole, have been described as the "ivory or 

 dentine membrane." 



REMARKS. 1. These villous projections were first seen by English investigators 

 (Huxley, Cfoodsir, Todd, and Bowman, II. cc.), and then more accurately described 

 at a later date, principally by Robin and Magitot. 2. The epithelium on the outer 

 surface of the enamel organ was also first recognised by English observers (Nasmyth, 

 ffuxley) ; but the French have made it an object of closer study ; comp. Guillot, I. c., 

 Robin and Magitot (Journ. de la physiol., Tome 4, p. 71). 



155. 



The dental germ is now destined, with the odontoblasts, to produce 

 dentine. To this end the elements in question send out long filiform 



of a lmman molar tooth wi i incipient 

 ; * 8 - 



processes externally, which constitute the soft dental fibres of Tomes, 



already known to us from 151. Between them a homogeneous 



stance then makes its appearance, whose origin must be accepted as 



>emg similar to that of the intercellular matters of the connective-tissue 



