TOMES, ON THE DENTAL TISSUES. 99 



of the cavities, by which means tlie teeth are allowed to come iu some 

 measure forward. In consequence of this absorj^tion it often happens, 

 that not only the socket of the corresponding temporary tooth, but that 

 of the tooth on each side is also opened to the permanent one. Absorption 

 now commences in the root of the temporary tooth, generally on that 

 part nearest its successor, and thus goes on by degrees as the latter 

 advances, until the root is completely removed, the crown at length falls 

 off, leaving room for the permanent tooth to supply its p>lace." 



Mr. Bell, however, rejects the idea that rriere pressure of 

 the one tooth against the other has anything to do with the 

 absorption of the first set ; an opinion that he would probably 

 have expressed even more strongly, had he observed the 

 shallow but perfect sockets which are formed when the tem- 

 porary teeth are shed before their successors are ready to 

 appear. This, however, must be a very common condition, 

 as I have in my own collection several specimens illustrating 

 the point. 



The fact was not overlooked, I think, by Hunter, although 

 his description is not very clear. He states at page 99 in his 

 'Natural History of the Teeth: ' " The new alveoli rise with 

 the new teeth, and the old alveoli decay in proportion as the 

 old teeth decay ; and when the first set falls out, the succeed- 

 ing teeth are so far from having destroyed by their pressure 

 the parts against which they might be supposed to push, 

 that they are still enclosed and covered by a complete bony 

 socket. From this we see that the cliange is not produced by 

 a mechanical pressure, but by a particular process in the 

 animal economy." 



But there is still a disposition on the part of many who are 

 intrusted with the treat/nent of teeth, to attribute the absorp- 

 tion of the roots of the one tooth to pressure occasioned by 

 the growth of its successor, and the development of the per- 

 manent may have something to do with the shedding of the 

 other. But this does not offer a satisfactory explanation of 

 all the circumstances attending the absorption of the fangs of 

 teeth. In the first place we sometimes meet with cases in 

 which the fangs of permanent teeth are as completely ab- 

 sorbed as those of the temporary organs. Then, again, the 

 fangs of temporary teeth, which have no successors, are also 

 absorbed. These circumstances, taken with the hitherto 

 overlooked fact, that with the waste of the temporary tooth 

 we have pretty genex'ally a corresponding development of 

 bone within the socket to be removed before the permanent 

 tooth appears through the gum, render the pressure theory 

 somewhat unsatisfactory. Another condition may be ad- 

 duced, tending also against that opinion, namely, that tem- 

 porary teeth occasionally maintaiii their place to the exclusion 



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