The Dental cosmos . dfifty to two hundred pounds. It is more or less curved outwardand upward, gradually tapering fromthe base to the apex, and contains aconical cavity extending to varyingdistances from the base toward theapex (the pulp-chamber). The cross-section is round or slightly com-pressed (elliptical). The tusks are deeply implanted inthe intermaxillary bones, reaching tothe floor of the nasal cavity, the alve-olar portion having in the adult alength of one to one and one-halffeet. (See Fig. 5.) The pulp of the elephant-tusk isan organ of great size, scarcely to becompared with the pu
The Dental cosmos . dfifty to two hundred pounds. It is more or less curved outwardand upward, gradually tapering fromthe base to the apex, and contains aconical cavity extending to varyingdistances from the base toward theapex (the pulp-chamber). The cross-section is round or slightly com-pressed (elliptical). The tusks are deeply implanted inthe intermaxillary bones, reaching tothe floor of the nasal cavity, the alve-olar portion having in the adult alength of one to one and one-halffeet. (See Fig. 5.) The pulp of the elephant-tusk isan organ of great size, scarcely to becompared with the pulp of the humanteeth ; it extends in young animals farinto the free portion of the tooth,sometimes occupying as much asseven-eighths of the entire length ofthe tooth ; its shape in young teethapproaches that of the tusks, beingonly slightly less tapering. With the growth of the tusk the pulp not only gradually recedesfrom the apex, but it recedes faster than the whole tooth is shoved * Ostcographie (Elephas), p. Fig. 5.—Longitudinal section of a tuskwith its alveolus/j [a, alveolus; d, c, d,pulp ; e, nasal cavity. ( Part of a drawingafter Owen.) 344 THE DENTAL COSMOS. forward from the base, so that it actually diminishes in length, and inadult specimens may not extend as far as the border of the alveolus. I recently saw an enormous tusk, some eight feet in length, weigh-ing one hundred and sixty-six German pounds, which was practicallysolid throughout, the pulp-chamber comprising a cup-shaped cavityonly five and one-half inches deep. At the base of the tooth a constant production not only of dentineand cement, but also, at an equal rate, of pulp-tissue, takes place, sothat the whole tooth, pulp and all, is bodily pushed forward (or out)in the alveolus. At the same time the pulp-chamber is being graduallyfilled up by the deposition of ivory over the whole surface of the pulp Fig. 6.—Cross-section of a small nearly full tusk, showing the layer of cement, the narrowouter
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectdentist, bookyear1890
