TOMES, ON THE DENTAL TISSUES. 101 



supj)()sed by Mr. J. Salter to be vvliat lias been described in the 

 paper before referred to as a lacunal cell.* 



Tlie part of a tooth which has the jjreatest power of resisting 

 absorption, is that in immediate contact with the pulp. We find 

 examples in which a thin shell of dentine surrounds that organ, 

 while that around it has been in great part taken away. This 

 is, however, eventually removed, and the pulp itself changes 

 its character, and becomes an absorbent organ, or makes way 

 for that which is. In a fortunate selection we may find sec- 

 tions showing in one part dentine which has been but recently 

 formed, with its modular outline and contiguous cells, capable 

 of developing dentine; in another part absorption in active 

 progress ; and in a third the deposition of bone on the surface 

 of the wasted dentine. In no instance, however, have I seen 

 dentine deposited upon the surface of that which has been 

 diminished by absorption. 



It would appear that tlie dentinal pulp, although its func- 

 tion may be changed into that of absorption, or its place be 

 taken by an absorbent organ, and this, again, changed to one 

 for the development of bone, is incapable of resuming under 

 any recognised circumstances its primary function of dentinal 

 development. In other words, that a portion of dentine wlien 

 removed by absorption, cannot be replaced ;| while in bone, 

 or cementum, the removal of a lost portion is of frequent occur- 

 rence. Sections taken from the teeth of adults seldom fail to 

 exhibit points where the cementum has been removed and 

 again added ; and very commonly the absorption has at points 

 extended a short distance into the dentine, and the lost parts 

 made good with cementum. Tliis condition may be observed 

 in perfectly sound teeth ; but in unsound ones, where the 

 cementum exceeds the normal amount, the removal and renewal 

 of tissue is still more marked. If the section be so made 

 as to give a view of the surface of the pulp cavity, we shall 

 probably find evidence of the pulp after the full develop- 



* Transactions of the Pathological iScciety, vol. vi., p. 169. 



t Since the manuscript was sent to the Editors of this Journal, I have 

 seen a papcir published in the last number of the Guy's Hospital Ileiiorts, 

 by Mr. J. Salter, ' On Intrinsic Calcification of the Permanent Tooth- 

 pulp.' Mr, Salter describes a section taken from a carious temporary 

 molar, which was removed from the moutli of a person aged 18 years. 

 The author states, that the " piilp was found converted into a mass of 

 crusta petrosa and dentine confounded together."' The drawing is beauti- 

 fully executed, and shows, by the usual indications, that the ]iulp-cavity 

 has been enlarged by absorption of its parietes. Judging from a view of 

 the engraving only, it would ajipeav that the tissue in contact with the 

 wasted dentine is cementum only, while the newly-developed dentine is 

 limited to the inner portion of the mass. If this view be correct, the 

 specimen would have served for the illustration of the present paper. 



