Human physiology (Volume 2) . sh fluid is observed to bepoured out from the inner surface, which is soon consolidated intoa dark, chalky substance, and afterwards becomes white and hard. At birth, the coronas of the incisors are formed; those of thecanine are not completed; and the molares have only theirtubercles. The root or fang is formed last of all. As ossificationproceeds, the corona of the tooth presses upon the gum, a portionof the follicle being interposed, which is gradually absorbed aswell as the gum ; and the tooth issues. The age at which the teeth make their appearance varies. Oc
Human physiology (Volume 2) . sh fluid is observed to bepoured out from the inner surface, which is soon consolidated intoa dark, chalky substance, and afterwards becomes white and hard. At birth, the coronas of the incisors are formed; those of thecanine are not completed; and the molares have only theirtubercles. The root or fang is formed last of all. As ossificationproceeds, the corona of the tooth presses upon the gum, a portionof the follicle being interposed, which is gradually absorbed aswell as the gum ; and the tooth issues. The age at which the teeth make their appearance varies. Occa-sionally, children have been born with them, whilst in other casesthey have not pierced the gum until after the period we are con-sidering. Generally, the middle incisors of the lower jaw appearabout the seventh month, and subsequently those of the upperjaw ; next the inferior and superior lateral incisors in succession ;then the first lower molares, and the first upper; next the inferior vol. n. — 44 518 AGES. Fig. 1. Front view of the temporary 279. and superior canine teeth, successively; and, lastly, the second molares of eachjaw. The ap-proximate timesof their appear-ance are thusestimated byMr. From five toeight months,the four centralincisors. From sevento ten, the fourlateral incisors. From twelveto sixteen, thefour anteriormolares. From four-teen to twenty,the four canine. From eigh-teen to thirty-six, the fourposterior The subjectof the intimateanatomy anddevelopment ofthe teeth hasbeeninvestigat- o. Central incisor. 6. Lateral incisor, c. Canine, d. First molaris. ed of late yearse. Second molaris. , J ?> by many ob-servers, whose contributions are well worthy of perusal. Amongstthe most important are those of Frankel, Raschkow, Retzius, Ar-nold, Goodsir,c Owen, and Nasmyth ;d and a recent writer has » The Anatomy, Physiology, and Diseases of the Teeth, Lond. 1829. See, also,Dr. Ashburner, Lectures on Dentition, Med.
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