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9 exceeds all other bony fubftances. When this mucous matter has formed itfelf into a vitreous confidence, the root of the tooth begins immediately to oflify, and is foon completely formed ; it now cuts the membrane that enclofes it, and the one that covers the focket, and foon after the gum : the teeth then begin to ap pear as we behold them white and beautiful. Of the Eruption of the Teeth. Children at their entrance into this world have ge nerally no teeth : cafes have occurred, however, where two, three, or four of the incifores have been found, but this very feldom happens. The ufual period for the firft of the teeth of infants is in the fifth, appearance fixth or eight month after their birth ; the two fmall in cifores in the maxillary inferior firft make their appear ance, the large incifores of the maxillary fuperior fol lowing them nearly at the fame time ; in a few weeks they are followed by two others by the fide of the firft in the under jaw, and fhortly after the other two in the upper jaw. — When the child is eleven or twelve months old the lower canini appear, and in a few days after the upper canini likewife ; the latter generally produc ing in their eruption much greater pain than the for mer. — When children are about eighteen or twenty months old, the two fmall molares in the under jaw make their appearance, and fhortly after the other two in the upper jaw : about the age of two years the one at each fide of other four fmall molares appear, their predecefiors ; thefe conftitute what is called the milk teeth; no more appearing until about the fixth — This arrangement, however, is not always ex year. act, for we fometimes fee the fmall molares fhoot forth before the canini. At about the age of fix years, four other molares appear adjoining thole preceding them ; between the eleventh and twelfth year four more and in the feventeenth or molares likewife appear, four others ; the whole number making eighteenth year