The general mass of it is made up of very minute granules; but, imbedded in this matrix, are innumerable bodies,

In the Grotto d'Arcès, a human jaw-bone and teeth have been found imbedded with Elephas primigenius, Ursus spelaeus, Hyaena spelaea, and other extinct animals, under layers of stalagmite.

THE PARATHYROIDS Sometimes imbedded within the substance of the thyroid in the neck, sometimes placed directly behind it upon the windpipe, are four tiny glands, each about the size of a wheat seed, the parathyroids.