Substance of a lecture on the functions of the mouth, and the structure of recent and fossil teeth / [Alexander Nasmyth].

  • Nasmyth, Alexander, 1758-1840
Date:
[1840]
Catalogue details

Licence: Public Domain Mark

Credit: Substance of a lecture on the functions of the mouth, and the structure of recent and fossil teeth / [Alexander Nasmyth]. Source: Wellcome Collection.

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    SUBSTANCE OF A LECTURE OK THE FUNCTIONS OF THE MOUTH, AND THE STRUCTURE OF RECENT AND FOSSIL TEETH. Delivered, at the Royal Institution, April 10, 1840, By A. NASMYTH, Esq. [From the London Medical Gazette.] Mr. Nasmyth delivered, at the Royal Institution, a very interesting lecture,— “ On the Functions of the Mouth, and the Structure of Recent and Fossil Teeth.’’ It comprehended a sketch of the process of assimilation, in the most extended sense of the term, as denoting that organic function by which anything whatever is converted into the nature or substance of another. The lecturer explained that it was to the .exercise of this function that all vital changes were to be referred, and that, were it paralyzed, the tide of life, which now holds on in one steady, undeviating, unremitting course, from the lowest vegeta¬ ble up to man, would instantly become stagnant. Nor is the organic world alone affected by its operation : the crust of the earth fulfils the office, as it were, of a general mouth and stomach to plants, from which their roots unceasingly derive nourishment; and the air contributes to animal assimilation by modifying the blood in the lungs, whilst, in plants, it acts in a similar manner on the juices in the leaves. Thus is every part of this globe pervaded, as it were, by the current of assimilation. With respect to the changes constantly taking place in the animal frame, Mr. Nasmyth strikingly remarked, that it is only after death has entirely re¬ moved the whole body from the sphere of vitality that any part of it assumes a cha¬ racter of permanency; but that then such is the indestructibility of some parts of that same animal structure, which, whilst living, had been undergoing incessant change, that they will be found to have en¬ dured through a lapse of countless ages, the extent of which the geologist alone can calculate, and to be altogether unaffected by the convulsions which, during that vast period, have rent the bosom of the earth in which they have been reposing. The lec¬ turer then proceeded to describe the mouth as the original and essential constituent of the assimilative apparatus, which, he said, even in its most perfect form, may be re¬ garded as merely a complicated extension of the buccal cavity, whilst, in its simplest form, it comprises nothing more than a rudiment of the latter. In the lowest classes of animals, however, it must be remembered, the different forms of the organization of the mouth are as peculiar to their respective species, as strictly adapted to the particular requisitions of the individual, and as typical of the whole system of the animal, as in the highest. The lecturer next gave a brief sketch of the organs of assimilation in their progress from their most elementary condition in the zoophyte to their most perfect in the mammalia. Wanting time to particularize their especial modifications in each class, he selected the mouths and teeth of aquatic and amphibious animals for more pro¬ minent consideration, shewing how they were in beautiful harmony with their pecu¬ liar requisitions. The mouths of the dol¬ phin, crocodile, shark, and lepisosteus, were exhibited as incomparable examples of machinery for seizing, holding, and dividing the‘bodies of their slippery prey. Indeed, the whole of this part of the dis¬ course was illustrated by a great variety of