Page:Natural History (1848).djvu/149

Rh year, the third set come gradually forward as the jaw lengthens, not only to fill up this additional space, but also to supply the place of the second set, which are, during the same period, gradually worn away, and have their fangs absorbed. From the beginning of the sixth to the end of the ninth year, the fourth set of grinders come forward to supply the gradual waste of the third set. In this manner, to the end of life, the Elephant obtains a set of new teeth, as the old ones become unfit for the mastication of its food.

"The milk-grinders consist each of four teeth, or damine; the second set of grinders of eight or nine lamine; the third set of twelve or thirteen; the fourth set of fifteen, and so on to the seventh or eighth set, when each grinder consists of twenty-two or twenty-three: and it may be added, that each succeeding grinder takes at least a year more than its predecessor, to be completed."

As each tooth advances, only a small portion pierces the gum at once; one of twelve or fourteen laminæ, for instance, shews only two or three of these through the gum, the remainder being as yet imbedded in the jaw; and in fact the tooth is complete at its fore part, where it is required for mastication, while behind it is still very incomplete; the laminæ are successively perfected as they advance. The molar of an Elephant can never, therefore, be seen in a perfect state; for if it is not worn in front, the back part is not fully formed, and is without fangs; and when the structure of the hinder portion is perfected, the front part is already gone.

If the reader will glance at the section of an Elephant’s skull, represented at page 131, he will see an illustration of these processes: the first