one
found at the very beginning of life upon earth. This problem brings us
to the threshold of astronomy; for the base of limestone is metallic in
character, susceptible therefore of fusion, and may have formed a part
of the materials of our earth, even in an incandescent state, when the
worlds were forming. But though this investigation as to the origin of
lime does not belong either to the naturalist or the geologist, its
suggestion reminds us that the time has come when all the sciences and
their results are so intimately connected that no one can be carried on
independently of the others. Since the study of the rocks has revealed a
crowded life whose records are hoarded within them, the work of the
geologist and the naturalist has become one and the same; and at that
border-land where the first crust of the earth was condensed out of the
igneous mass of materials which formed its earliest condition, their
investigation mingles with that of the astronomer, and we cannot trace
the limestone in a little coral without going back to the creation of
our solar system, when the worlds that compose it were thrown off from a
central mass in a gaseous condition.

When the coral has become in this way permeated with lime, all parts of
the body are rigid, with the exception of the upper margin, the stomach,
and the tentacles. The tentacles are soft and waving, projected or drawn
in at will; they retain their flexible character through life, and
decompose when the animal dies. For this reason the dried specimens of
corals preserved in museums do not give us the least idea of the living
corals, in which every one of the millions of beings composing such a
community is crowned by a waving wreath of white or green or
rose-colored tentacles.

As soon as the little coral is fairly established and solidly attached
to the ground, it begins to bud. This may take place in a variety of
ways, dividing at the top or budding from the base or from the sides,
till the primitive animal is surrounded by a number of individuals like
itself, of which it forms the nucleus, and which now begin to bud in
their turn, each one surrounding itself with a numerous progeny, all
remaining, however, attached to the parent. Such a community increases
till its individuals are numbered by millions, and I have myself counted
no less than fourteen millions of individuals in a coral mass of Porites
measuring not more than twelve feet in diameter. The so-called cor