Three memoirs on the developement and structure of the teeth and epithelium, read at the ninth annual meeting of the British Association for the Encouragement of Science, held at Birmingham in August, 1839 / by Alexander Nasmyth.

Date:
1841
Catalogue details

Licence: Public Domain Mark

Credit: Three memoirs on the developement and structure of the teeth and epithelium, read at the ninth annual meeting of the British Association for the Encouragement of Science, held at Birmingham in August, 1839 / by Alexander Nasmyth. Source: Wellcome Collection.

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

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    appearance. A few examples of this structural arrangement are seen [at PL C. 6,] in the diagrams marked “ Ivory deprived of earth,” Nos. 1 to 4, showing its appearance after the earthy matter has been removed. Among the gigantic remains which are brought under the consideration of the geologist, there is one which to me is particularly interesting—I allude to the tusk of the mammoth. As found in our museums, it will be observed to present a lami- nated, concentric structure, being apparently com- posed of layers gradually increasing in size from the centre to the circumference. These layers in numerous instances are separated from each other by considerable spaces. The experiments of Hunter on animals fed on madder also lead to the con- clusion that the structure of the teeth is actually laminated; and the workshop of the mechanic, called by Professor Leslie the School for Philoso- phers, furnishes numerous facts in support of the same position : for instance, the circumstance that ivory is found to possess considerable strength if cut parallel to the long axis of the tooth, and that it is weak if cut at right angles. If we suppose that ivory consists only of fibres surrounded by a structureless material, passing from the centre to the circumference, we must conclude that at right angles to their course it would be most diffi- cult of fracture ; but the contrary is the fact, as is exemplified by the natural separation of the lamellae of the tusk of the mammoth in a direction