Volume 1

[Report of the Council respecting the publication of A. Nasmyth's papers on the structure of the teeth].

  • British Association for the Advancement of Science. Meeting
Date:
[1841]
Catalogue details

Licence: Public Domain Mark

Credit: [Report of the Council respecting the publication of A. Nasmyth's papers on the structure of the teeth]. Source: Wellcome Collection.

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    epithelium generally, a nucleus is first [found] f formed*, and then a cell is formed around it. These cells are connected by a gelatinous substance, in¬ terspersed with minute granular bodies, which displays considerable elas¬ ticity, and which sometimes presents a fibrous appearance. The granules can be caused to disappear by compression. In certain parts of the epithelium of the calf, distinct fibres are observed to pass over the surface of the scales, and to connect them together, thus forming a very delicate net-work. On the surface of the body and of the mucous membranes of man and animals gene¬ rally, the superficial scales are thrown off by pressure from the cells beneath. But in some cases, as with frogs and efts, the epithelium-scales are removed in a continuous layer, and Mr. Nasymth is disposed to believe that it is the covering which, according to naturalists, is swallowed by the animal after having been shed. The cuticle and epithelium then are evidently organized [tissues] f bodies*. It would appear that they are formed from a fluid secretion, and that their various stages of development are as follows: 1st, the formation of nuclei and their corpuscles; 2nd, that of cells; 3rd, the growth of the latter effected by vital imbibition; 4th, their compression and gradual conversion into minute lamellae or scales. The cells seem to have within themselves a power of growth, and it remains for pathologists to deter¬ mine what share the derangement of this function has in the production of cutaneous diseases. Under certain modifications the epithelium certainly pre¬ sents vital phasnomena, among which may be mentioned the ciliary motions. Mr. Nasmyth concluded his paper by an especial description of the portion of the epithelium lining the cavity of the mouth. In the foetal subject, pre¬ vious to the extrusion of the teeth, it forms on the alveolar arch a dense pro¬ jecting layer, distinguishable from the surrounding membrane by its whiteness, and by superficial and waving ridges and sulci. The younger the subject, the greater is its thickness. It is made up of a mass of scales lying one above the other, and thus presents no resemblance to cartilage, though it has been generally classed as such. In the interior of its structure, where it cor¬ responds to the molar teeth, small vesicles may be frequently observed, vary¬ ing in size from one-fourth to one-eighth of a line in diameter. On micro¬ scopic examination, the [parietes] -f particles* of these are found to consist of attenuated scales, and their cavity to contain a fluid abounding in minute granules and cells. They are probably the “glands” described by Serres as intended for the secretion of the tartar. Larger vesicles are also found im¬ planted in the vascular mucous membrane, composed of a very delicate tissue, and containing a transparent fluid, which coagulates on the application of heat or acid. In this fluid float numerous globules and scales, similar to those of the epithelium generally. The internal or attached surface of the alveolar epithelium presents numerous fringed processes, which sink into the sub¬ stance of the subjacent mucous membrane. These are found to be composed of elongated scales. By immersion in water or diluted spirits of wine, these fringes are much enlarged, and their size, indeed, exceeds that of the dense epithelium itself. (B.)—Dr. Lloyd's Abstract of Mr. Nasmyth's Paper read before the Geolo¬ gical Section at Birmingham ; printedfrom a copy preserved by Dr. Lloyd. “ During the author’s microscopic researches on the structure of teeth, he was led to the discovery of the organized nature of the interfibrous substance which Purkinje, Frankel, Retzius, and Muller have regarded as structureless, * The words in italics are in the Athenaeum, but are not in the original manuscript,