File:The Dental cosmos (1890) (14799017813).jpg

Identifier: dentalcosmos3218whit (find matches)
Title: The Dental cosmos
Year: 1890 (1890s)
Authors: White, J. D McQuillen, J. H. (John Hugh), 1826-1879 Ziegler, George Jacob, 1821-1895 White, James William, 1826-1891 Kirk, Edward C. (Edward Cameron), 1856-1933 Anthony, L. Pierce (Lovick Pierce), b. 1877
Subjects: Dentistry Dentistry
Publisher: Philadelphia, S. S. White Dental Manufacturing Co
Contributing Library: Yale University, Cushing/Whitney Medical Library
Digitizing Sponsor: The College of Physicians of Philadelphia and the National Endowment for the Humanities

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Text Appearing Before Image:
ks (Fig. 3, A) had to all appearance not yet brokenthrough the gums, and the point shows no signs of use whatever. Thistusk is 14.5 cm. long, 10.0 cm. in circumference at the base, wherethe wall is as thin as paper, and hollow to within 5.0 cm. of the apex.It possesses a double point, or rather the point resembles two teats,of which one is considerably shorter than the other. Except near thebase, it is enveloped in a thin sheath of a substance which, on micro-scopic examination, proved to be cement. The sheath is ruptured invarious places, and near the point a piece is broken out, revealingon its under surface a thin layer of enamel. At the base of the tooththe cement is wanting, or, in other words, has not yet been formed. We find, accordingly, that the permanent tusk of the elephant at thetime of eruption is provided with a coating of cement over its wholesurface (excepting at the base, where the dentine forms somewhat ^ANATOMY AND PATHOLOGY OF THE TUSKS OF THE ELEPHANT. 34I Fig. 3.
Text Appearing After Image:
Fig. 3.—A pair of very young permanent tusks of the elephant. Tusk A shows the pointunworn, covered with an external layer of cement which is broken away at a. Tusk B pro-jected over an inch beyond the gums, and is considerably worn at the point; both the cementandenamel have shelled off at a, exposing the ivory; at b the enamel is still preserved. Thedotted line represents the probable form of the point at the time of eruption. Nat. size. earlier than the cement), and that this coating at the apex of the toothis separated from the ivory by a thin layer of enamel. The left tusk (Fig. 3, B) reached about an inch beyond the gums 342 THE DENTAL COSMOS. and was considerably worn at the point, so as to expose both theenamel and the dentine. On this tusk the relation of the three tissuesis still more easily seen, and is of course the same as that revealed inthe opposite tusk. I have found the same relation of the three tissues on the points ofother tusks in my possession ; a cross-section

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