46 TOOIH-GEKMS. 



pulp, is a pliYsiological point of which a satisfactory 

 soiution remains to be given. "^ 



* Of tlie development of teetli in the human fetus Monsieur 

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

 The epithelial eminence and epithelial inflection of Kolliker 

 only may be scan 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 — Tiie 

 dentine bulb appears in juxtaposition with the downward ex- 

 tremity'of sthe enamel -organ. This stage occurs nearly simul- 

 taneously for the whole series of temro.c:./ 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 2)ermnnent 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 tlie corresponding deciduous teeth, 

 appear. S^'venteenth — 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 mo^ar. Ticentieth—E.\o^\\t of the dentine caps of the cen- 

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

 molars, .089. Appearance of dentine organ of permanent teeth, 

 and inclosure of wall and rupture of l)and of first molar. Tirenti/- 

 jlfth — Dentine caps, .07, .054. The permanent follicle walls, 

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

 tain distinctness. 2\ceiity-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. 

 Thirty-sccoud — Dentine caps, .113, .093. The first permanent 

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

 organ, have coalesced. Thirti/sixth— Dentine caps, .118, .109; 

 permanent molar. .004 to .039. Th:'rt7/-ninth— -Dentine caps, 

 .136, .lis ; permanent molar, .039 to .07S. The permanent follicle 

 walls close. The dentine caps appear one month after birth.'* 



