



Produced by Amy E. Zelmer





CORAL AND CORAL REEFS

by Thomas H. Huxley

[1]


THE subject upon which I wish to address you to-night is the structure
and origin of Coral and Coral Reefs. Under the head of "coral" there are
included two very different things; one of them is that substance which
I imagine a great number of us have champed when we were very much
younger than we are now,--the common red coral, which is used so much,
as you know, for the edification and the delectation of children of
tender years, and is also employed for the purposes of ornament for
those who are much older, and as some think might know better. The other
kind of coral is a very different substance; it may for distinction's
sake be called the white coral; it is a material which most assuredly
not the hardest-hearted of baby farmers would give to a baby to chew,
and it is a substance which is to be seen only in the cabinets of
curious persons, or in museums, or, may be, over the mantelpieces of
sea-faring men. But although the red coral, as I have mentioned to you,
has access to the very best society; and although the white coral is
comparatively a despised product, yet in this, as in many other cases,
the humbler thing is in reality the greater; the amount of work which is
done in the world by the white coral being absolutely infinite compared
with that effected by its delicate and pampered namesake. Each of these
substances, the white coral and the red, however, has a relationship to
the other. They are, in a zoological sense, cousins, each of them being
formed by the same kind of animals in what is substantially the same
way. Each of these bodies is, in fact, the hard skeleton of a very
curious and a very simple animal, more comparable to the bones of such
animals as ourselves than to the shells of oysters or creatures of that
kind; for it is the hardening of the internal tissue of the creature, of
its internal substance, by the deposit in the body of a material which
is exceedingly common, not only in fresh but in sea water, and which
is specially abundant in those waters which we know as "hard,"
those waters, for example, which leave a "fur" upon the bottom of a
tea-kettle. This "fur" is carbonate of lime, the same sort of substance
as limestone and chalk. That material is contained in solution in sea
water, and it is out of the sea water in which these coral creatures
live that they get the lime which is needed for the forming of their
hard skeleton.

But now what manner of creatures are these which form these hard
skeletons? I dare say that in these days of keeping aquaria, of
locomotion to the sea-side, most of those whom I am addressing may have
seen one of those creatures which used to be known as the "sea anemone,"
receiving that name on account of its general resemblance, in a rough
sort of way, to the flower which is known as the "anemone"; but being
a thing which lives in the sea, it was qualified as the "sea anemone."
Well, then, you must suppose a body shaped like a short cylinder, the
top cut off, and in the top a hole rather oval than round. All round
this aperture, which is the mouth, imagine that there are placed a
number of feelers forming a circle. The cavity of the mouth leads into
a sort of stomach, which is very unlike those of the higher animals,
in the circumstance that it opens at the lower end into a cavity of the
body, and all the digested matter, converted into nourishment, is thus
distributed through the rest of the body. That is the general structure
of one of these sea anemones. If you touch it it contracts immediately
into a heap. It looks at first quite like a flower in the sea, but if
you touch it you find that it exhibits all the peculiarities of a living
animal; and if anything which can serve as its prey comes near its
tentacles, it closes them round it and sucks the material into its
stomach and there digests it and turns it to the account of its own
body.

These creatures are very voracious, and not at all particular what they
seize; and sometimes it may be that they lay hold of a shellfish which
is far too big to be packed into that interior cavity, and, of course,
in any ordinary animal a proceeding of this kind would give rise to a
very severe fit of indigestion. But this is by no means the case in the
sea anemone, because when digestive difficulties of this kind arise he
gets out of them by splitting himself in two; and then each half builds
itself up into a fresh creature, and you have two polypes where there
was previously one, and the bone which stuck in the way lying between
them! Not only can these creatures multiply in this fashion, but they
can multiply by buds. A bud will grow out of the side of the body (I am
not speaking of the common sea anemone, but of allied creatures) just
like the bud of a plant, and that will fashion itself into a creature
just like the parent. There are some of them in which these buds remain
connected together, and you will soon see what would be the result of
that