On the structure of teeth, and the resemblance of ivory to bone, as illustrated by microscopical examination of the teeth of man, and of various existing and extinct animals / by Professor Owen.

Owen, Richard, Sir, 1804-1892.

Date:: [1838?]

Credit: On the structure of teeth, and the resemblance of ivory to bone, as illustrated by microscopical examination of the teeth of man, and of various existing and extinct animals / by Professor Owen. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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$c On the Structure of Teeth, and the resemblance of Ivory to Bone, as illustrated by microscopical examination of the Teeth of Man, and of various existing and extinct Animals. By Professor Owen, F.R.S. Mr. Owen commenced by showing, that he had availed himself of the advantage afforded by the British Association, viz. that in the com- munications brought before a sectional committee, a fuller and more detailed retrospect of the progressive steps which have led to any re- markable discovery, is not only permissible, but peculiarly congenial to its general views and objects; and he therefore entered into a full de- tail of the recent investigations, especially those of Purkinje, Muller, and Uetzius, on the intimate structure of the teeth, and particularly dwelt on the discoveries of the latter author, as regarded the structure of the human tooth. After describing the mode of arrangement of the particles of the earthy salts, which characterizes true bone, Professor Owen proceeded to state, that until a very recent period the analogy of tooth to bone was supposed to extend no further than related to the chemical composition of the hardening material, while the arrangement of this earthy constituent, as well as its mode of deposition during the growth of the entire tooth, were considered to be wholly different from that of bone, and to agree with the mode of growth of hair, and other so-called extra vascular parts, with which teeth in general closely cor- respond in their vital properties. He observed, that the supposed proofs of the laminated structure of teeth, derived from the appear- ances presented by the teeth of growing animals, fed alternately with madder and ordinary food, and by those which often occur during the progress of decomposition of certain teeth, which are then resolved into a series of concentric or superimposed laminae, were equally ap- plicable to true bone, and were quite unavailable in illustrating the point under consideration; and that the appearances presented by the superficies of vei’tical sections of teeth, viewed with the naked eye or a low magnifying power, were due, not to the intervals of separate and superimposed lamellae, but to the different refractions of light, caused by the parallel undulations or alternations of structure of minute tubes proceeding in a contrarj’^ direction to the supposed lamellae. This ap- parent lamellated structure, however, is not constant, nor equally plain in different teeth ; on the contrary, the fractured surface, or the polished section of the human ajid many other teeth, presents a silky or irides- cent lustre, which has attracted the attention of several anatomists. Pro- fessor Owen observed, that Malpighi, in whose works may be detected the germs of several important anatomical truths, which have subse- quently been matured and established, conceived that the teeth were composed of minute fibres reticularly interwoven ; and Leewenhoek, in vor.. VII. 1838. k$