On the origin and development of the pulps and sacs of the human teeth / by John Goodsir.

  • Goodsir, John, 1814-1867.
Date:
[1840-?]
Catalogue details

Licence: Public Domain Mark

Credit: On the origin and development of the pulps and sacs of the human teeth / by John Goodsir. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    the latter reaches the base of the pulp the former disappears, and the interior of the dental sac assumes the villous vascular ap- pearance of a mucous membrane. This change is nearly com- pleted about the seventh or eighth month. Up to this period little change has taken place in the ten an- terior, or in the two posterior or great cavities of reserve. The ten anterior have been gradually receding from the surface of the gum, so as to be posterior, instead of inferior, to the milk sacs. The two or four anterior began about the fifth month to dilate at their distal extremities, across which a fold appears (which is the germ of the future pulp) lying in the direction of the cutting edge of the future tooth ; and at the proximal or acute extremities of the cavities two other folds, an anterior and a posterior appear. * These round off the undefined apices of the cavities, and are strictly analogous to the opercula of the milk follicles. The distal fold gradually acquires the appearance of a tooth pulp, while the proximal disappear by the obliteration of the little undefined space beyond them. The cavities of reserve have now become tooth sacs, and under this form they continue to recede from the surface of the gum, imbedding themselves in the submucous cellular tissue, which has all along constituted the external layer of the milk sacs, and in which the larger saccular vessels ramify before arriving at the true mucous membranes of the sacs. This implantation of the perma- nent, in the walls of the temporary tooth sacs, gives the former - the appearance of being produced by a gemmiparous process . from the latter.f The dental groove was originally imbedded in an alveolar groove. As the dental interfoUicular septa are developed in the ' Tliese two folds are strictly analogous to the opercula of the milk tooth sacs. They never attain, however, the same high developement as those of the latter, re- maining in a rudimentary state, apparently in consequence of the almost saccular condition of the cavities of reserve. The existence of these Inniinse in a rudimen- tary state proves, that, in the formation of the permanent teeth, there is a strict ad- herence to the law of follicular developement, even when, in man at least, there is no apparent necessity for it. ^ It was this imbedding of the permanent, in the walls of the temporary, tooth sacs which deceived Dr Blake, and led him to suppose that the former derived their ori- gin from the latter. Mr Fox supported the same view of the subject; and Mr Bell, in his own work, (Anatomy, &c. &c. of the Teeth, p. 61,) and more lately in his notes in Palmer's edition of Mr Hunter's Works, Vol. ii. p. 37, has strongly urged the same doctrine. Mr Bell has stated, that Mr Hunter's account of the manner in which the permanent teeth arc formed is exceedingly imperfect; but it is evident, that, if the account of the origin of these teeth given in the text be correct, Mr Hunter was not in error when he supposed both sets to be of independent origin. Mr Hunter was so correct a thinker, that he did not account the circumstance of contiguity to be a proof of dependence. He was apparently ignorant of the origin of botli scis, and in his usual cautious manner, when dacrihiiig structure^ makes no observation on the subject. The author of the Edinburgh Ditsector holds tiic same opinion as Mr Hunter on this subject; and in his excellent chapter on the teeth, although he doc« not disprove the opinions of Dr Blake and others, cautions the student against iupposing Mr Hunter to be incorrect on this subject.