Evening star., 1902-01-29
HOW CORAL INSECTS BUILD
a PReBLEN THAT Long WAS A
reSER TO NArTRsrasrS.
The ISOLATION offered by Darwiu
seventy S~srs Ago Now Conn
monty Accepted.
from the St. Louis Giobe-Demoocrat.

From the ST. Louis Globe e-Dcmoccrat-
Among all the varied productions OF living
nature none can perhaps vie in respect OF
interest with those of the coral animal
From our boyhood's days we have been ac-
customed to read OF coral islands. but II is
to be feared that many of the descriptions
given of these structures In the tales WE
pered over In our youth must be ranked
more successful ventures in the Isne OF
fiction than in that of actual science. Yet
the scientific side of the story of coral Is
quite as wondrous In its way as anything
which the fertile brain OF the story writer
is able to conceive.
Every one is familiar, from a visit TO a
natural history museum. with the general
appearance Of coral. There are, of course,
very many different species OF structures
included under this common name. We see
great masses Of stony hardness assuming
fantastic shapes. and constituting IN their
delicate description and may assume the
form OF miniature organ pipes, while the
RED coral itself, so much valued for the
manufacture of articles of jewelry, repre-
serts the opposite extreme from the coarse
hmy masses referred TO. 1 may explode at
the outset an erroneous idea regarding the
red coral. This coral il practically confined
te Inc mediterranean sea and grows IN a
formed OF red coral exist is a piece of pure
hction, and those coraIs which more cspe-
cially concern us here the builders of
reefs are represented by the coarse stony
masses familiar in museums, but also often
used I'm the construction of grottoes and
ferneries.
Not nm Old Discovery.
1t is not so very long ago In the history
of science that coral was discovered TO be
the work of an animal. The ancients re-
garded coral. and especially the led coral,
which they knew best, as the work of the
marine plant. Latin poets tell as OF the
coral plant, which is soft I'm is native
waters. but becomes hard when drawn up
from the sea and exposed to the action of
the air. young French student. Peyson-
mel discovered the fact that coral ~as a
substance represented by the secretion of
an animal He described accurately enough
the Kind of animal which makes coral. He
compared this animal to the sea anenone
winch we find in every rocky hollow around
our own coasts. In so doing he was p..Y--
fectly correct, for the coral animal is realty
a Kind of insect and familiar denizen OF
the seaside.
There is, however. this difference between
the latter and the coral animal The for
nier, as a rule, is a single animal. the COR
aus are usually compound. That is to say
one coral animal gives rise to another by a
process OF budding, and in this way a mass
OF coral is seen to be the work not OF one
animal. but of many hundreds of thousands
produced as a kind of colony in the way
just described Ii is this power of increase
by budding which enables corals TO con-
struct reefs of great magnitude Possessing
Wnat is practically unlimited power Of
increase, they succeed in producing enpr-
NOUS masses of rocky substance, and .e
must not forget that every coral animal has
the power of producing eggs Each egg
which comes to full development settles
down, gives origin to one coral animal and
as this In turn buds like its forefathers, a
new COLONY is thus
Carbonate of Lime.
Regarding coral itself. We find that SUBJ
stance to be represented by hard carbon
ate of lime. The matter which we find ac-
cumuiated in boilers and kettles I'm hard
water districts nearly as possible repre-
sents the coral substance. The material for
making this hard secretion, the possession
of which also constitutes another difference
from the sea anemone is obtained from the
sea water. Carbonate of lime exists in So
luton IN the water, and the coral animals
absorbing this material from the sea, build
II up In the form of their hard parts either
within or without their bodies. In this WAY
when the coral animals themselves die they
leave behind them what a poet has wei
called 'the imperishable masonry of the
sea-" The power of budding is not of
course. limited to corals. We are familiar
enough with it in the case of plants, but
many other animals besides corals grow
into colonies by the budding process
Corals can also add to the number in a
colony through another process, namely
simple division of the body. We see how
the body simply divided in two gives rise to
two individuals, and thus adds to the nu-
merfcai strength of the mass. The condi-
uons under which corals live and grow are
very simple. They may be summed up fn
the words-a certain heat and certain
death. The question Of heat naturally set
ties the range of the corals in space; that
is determines their geography in the exist
ing earth The reef-building corals do not
flourish in seas where the water is below GO
degrees or thereby of Fahrenheit. 1t will
therefore be seen that IL is only In tropical
regions where we may expect to find the
fullest development of coral life.