PULPS AND SACS OF THE HUMAN TEETJI. 45 



On the Anterior Pcnnanent Molar Teeth. — The anterior 

 permanent molar is the most remarkable tooth in man, as it 

 forms a transition between the milk and permanent set. If 

 considered anatomically, it is decidedly a milk-tooth ; if 

 j)hysiologically, a permanent one. In a former part of this 

 paper, it was stated that the papilla and follicle of this tooth 

 were developed in a small portion of the primitive dental 

 groove, which remained open for that purpose till the fourth 

 or fifth month, while all the other permanent teeth were pro- 

 ductions, not from the primitive gioove, but from small 

 non-adherent portions of the secondary groove, which lay in 

 a level superior to the shut orifices of the sacs of all the milk- 

 teeth, and of the tooth in question — the first permanent molar. 

 In reference to its function, however, as the most eflBcient 

 gi'inder in the adult mouth, we must consider it as a permanent 

 tooth. It is a curious circumstance, and one which will readily 

 suggest itself to the surgeon, that, laying out of view the 

 wisdom-teeth, which sometimes decay at an early period from 

 other causes,* the anterior molars are the permanent teeth, 

 which most frequently give way first, and in the most sym- 

 metrical manner, and at the same time, and frequently before 

 the milk set. 



On the Tardy Development of the Superior Incisive Teeth. — 

 A reference to the first section of tliis paper will show that at 

 the ninth week, when the papillte of the superior incisives are 

 quite distinct, those of the inferior are- with difficulty recog- 

 nisetl. This is a fact which may be included imder a law 

 which will be more fully referred to afterwards — viz. that the 

 dentition of the upper precedes, and is always in advance of, 

 the same process in the lower jaw. A week or two later, 

 however, when the papillae of the inferior incisives are 

 imbedded and hid in deep follicles, those of the superior are 



* liell, Aiwt. .to. of the TalJi, p. 133. 



