a home in such deep waters is
genial has established itself. How it happens that such a being, which
we know is immovably attached to the ground and forms the foundation of
a solid wall, was ever able to swim freely about in the water till it
found a suitable resting-place, I shall explain hereafter, when I say
something of the mode of reproduction of these animals. Accept, for the
moment, my unsustained assertion, and plant our little Coral on this
sloping shore some twelve or fifteen fathoms below the surface of the
sea. The internal structure of such a Coral corresponds to that of the
Sea-Anemone: the body is divided by vertical partitions from top to
bottom, leaving open chambers between, while in the centre hangs the
digestive cavity connecting by an opening in the bottom with all these
chambers; at the top is an aperture which serves as a mouth, surrounded
by a wreath of hollow tentacles, each one connecting at its base with
one of the chambers, so that all parts of the animal communicate freely
with each other. But though the structure of the Coral is identical in
all its parts with that of the Sea-Anemone, it nevertheless presents one
important difference. The body of the Sea-Anemone is soft, while that of
the Coral is hard. It is well known that all animals and plants have the
power of appropriating to themselves and assimilating the materials they
need, each selecting from the surrounding elements whatever contributes
to its well-being. The plant takes carbon, the animal takes oxygen, each
rejecting what the other requires. We ourselves build our bones with
the lime that we find unconsciously in the world around us; much of our
nourishment supplies us with it, and the very vegetables we eat have,
perhaps, themselves been fed from some old lime strata deposited
centuries ago. We all represent materials that have contributed to
construct our bodies. Now Corals possess, in an extraordinary degree,
the power of assimilating to themselves the lime contained in the salt
water around them; and as soon as our little Coral is established on a
firm foundation, a lime deposit begins to form in all the walls of its
body, so that its base, its partitions, and its outer wall, which in
the Sea-Anemone remain always soft, become perfectly solid in the Polyp
Coral and form a frame as hard as bone. It may naturally be asked
where the lime comes from in the sea which the Corals absorb in such
quantities. As far as the living Coral