Researches on the developement, structure and diseases of the teeth. / by Alexander Nasmyth.

  • Nasmyth, Alexander, 1789-1849
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Researches on the developement, structure and diseases of the teeth. / by Alexander Nasmyth. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    HISTORICAL INTRODUCTION. According to our author, the fluid of the follicular cavity differs in many respects from that of serous mem- branes, being more consistent and viscid, of a dark yellow colour, and possessing, moreover, peculiar properties, which Berzelius states to be owing to the presence of lactic acid. Blandin considers that the relation between the dental papilla and the tooth is not analogous to that existing be- tween primitive cartilage and bone; since the papilla does not ossify, any more than the papilla of a hair or a feather solidifies in order to produce those structures. He imagines that the tooth is secreted by the external surface of the papilla on which it rests ; that it takes the exact form of the latter, and increases in length and thick- ness in the same way as hair, feathers, and nails—that is to say, by the successive addition of layers internally to those already secreted. In regard to the production of the enamel, he allows that its origin is involved in great obscurity, and notices the conflicting opinions respecting it—Cuvier holding that it is produced by an immediate secretion from the inter- nal layer of the follicle, whilst Hunter states that it remains for some time dissolved in the fluid of the follicle, and afterwards crystallises on the ivory of the tooth ; and whilst others have held that it is also secreted by the pulp, and traverses the pores of the ivory in order to arrive at the surface. If any of these theories are adojited, it is difficult to explain why the root of the tooth, which, like the croAvn, is formed on the papilla in the cavity, and in the midst of the cavity of the follicle, should not be also covered with enamel. M. Delabarre has tried to solve tliis difficulty : he holds tliat the enamel is secreted ])y the internal layer of the follicle, but that this layer