File:Dental cosmos (1893) (14592546648).jpg

Identifier: dentalcosmos3518whit (find matches)
Title: Dental cosmos
Year: 1893 (1890s)
Authors: White, J. D McQuillen, J. H. (John Hugh), 1826-1879 Ziegler, George Jacob, b. 1821 White, James William, 1826-1891 Kirk, Edward C. (Edward Cameron), 1856-1933 Anthony, Lovick Pierce, 1877-
Subjects: Dentistry
Publisher: Philadelphia : S. S. White Dental Manufacturing Co
Contributing Library: The College of Physicians of Philadelphia Historical Medical Library
Digitizing Sponsor: The College of Physicians of Philadelphia and the National Endowment for the Humanities

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cceeded in discovering the so-calledreserve cells described by Waldeyer and others. Those authors weredoubtless deceived by sections oblique and not sufficiently thin. Count Spee proved first that the young enamel is stained black byosmic acid ; also in the enamel-cells there are found, after treatmentwith osmic acid, here and there a few black globules, which must be ii94 THE DENTAL COSMOS. regarded as the first products of the change of the enamel-cells intothe ground-substance of the enamel (Fig. 4, SEi). Young enamelhas about the appearance of a honeycomb. In the depressions thereare processes of the enamel-cells, the so-called Tomess processes(Fig. 4, T). In the enamel-cells, as in the odontoblasts, those endsof the cells which point toward the enamel are changed into enamel ;the opposite end of the cell, which contains the nucleus, continues togrow by taking up new nutriment, up to the time when the enamelceases to form. The last curious horny product of the enamel-cells Fig. 5.
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Fig. 5.—Human foetus (30 cm. long). First milk incisor. Frontal section through lower jaw.D.K, dentine germ; Od, odontoblasts; K, bone of the alveoli ; SE.a, outer, SE.i, inner enamelepithelium ; S.P, enamel-pulp; Z.F, dental furrow; Af.E, epithelium of the jaw; Z.L, dentalridge ; E.L, reserve ridge for the reserve tooth; V.B, connecting bridge ; Jl.ii, second incisorcut along its periphery. 300 diam. is the enamel cuticle. The young enamel is first an organic matrixrich in salts of lime, exactly like the uncalcified dentine. As soon asthe proper calcification begins, the salts of lime are deposited first inthe prolongation of Tomess processes, and form thin prisms whichare surrounded by a large amount of an organic cementing substance.Also, this substance calcifies by degrees, and so the prisms growthicker. Finally there remain only faint traces of a cementing sub- HISTOGENY AND HISTOLOGY OF BONY AND DENTAL TISSUES. II95 stance between the enamel-prisms. In teeth in which the ename

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