46 TOOTH-GERMS. 



pulp, is a physiological point of which a satisfactory 

 solution remains to be given.* 



* Of the development of teetli in the human fetus Monsieur 

 E. Magitot says (" Comtes Rendus," 1874) : "Seventh Week 

 The epithelial eminence and epithelial inflection of Kolliker 

 only may be seen at the edge of the jaw. The superior maxil- 

 lary and intermaxillary bones are not united, and the inferior 

 maxillary arch contains Meckel's cartilage only, without any 

 trace of bone. The epithelial bands (enamel-organs) are succes- 

 sively formed in the order of their designation. Ninth The 

 dentine bulb appears in juxtaposition with the downward ex- 

 tremity of the enamel-organ. This stage occurs nearly simul- 

 taneously for the whole series of temporary follicles. Tenth 

 The wall of the follicle detaches itself from the base of the bulb 

 and rises up its sides. Fifteenth The epithelial band begins 

 its transformation into an enamel-organ. The enamel-germ of 

 the first permanent molar may now be seen springing from the 

 epithelial inflection. Sixteenth The wall of the follicle is 

 closed. The epithelial band is broken, and the follicle thencefor- 

 ward has no connection with the surface epithelium. The epi- 

 thelial bands of the permanent teeth, which are derived from the 

 necks of the enamel-organ of the corresponding deciduous teeth, 

 appear. Seventeenth Appearance of the cap of dentine of the 

 central and lateral incisors ; also the bulb of the first permanent 

 molar. Eighteenth Appearance of the dentine caps of the first 

 and second molars ; also the wall of the follicle of the perma- 

 nent molar. Twentieth Right of the dentine caps of the cen- 

 tral incisor, lateral incisor, and canine, .059 ; first and second 

 molars, .039. Appearance of dentine organ of permanent teeth, 

 and inclosure of wall and rupture of band of first molar. Twenty - 

 fifth Dentine caps. .07, .054. The permanent follicle walls, 

 which appeared after the twenty-first week, have acquired a cer- 

 tain distinctness. Twenty-eighth Dentine caps, .093, .078. The 

 epithelial germs of the permanent follicles begin their transfor- 

 mation into enamel-organs; dentine cap first molar, .003 to .007. 

 TJdrty -second Dentine caps, .113, .093. The first permanent 

 molar cusps, which form upon the several apices of the dentine 

 organ, have coalesced. Thirty-sixth Dentine caps, .118, .109 ; 

 permanent molar, .004 to .039. Thirty-ninth Dentine caps, 

 .136, .118 ; permanent molar, .039 to .073. The permanent follicle 

 walls close. The dentine caps appear one month after birth." 



