Year: 1873

Sponge, these hard parts are made up of
horny hair-like threads, or tubes, which
extend in every direction, and which are
so closely woven together and interlaced,
that they form very fine network; this
Sponge is very soft and elastic and even
after severe pressure, takes its original
shape when released. Other kinds are
sitter and firmer in texture, and this
stiffness is owing to very minute crystals,
or particles of earthly matter which are
scattered through the horny portions.
and help to make up the framework.
These minute crystals are called spicule,
or little spikes, and in some kinds of
Sponge they are pure flint, or quartz; in
other kinds they are limestone. These
little spikes are not always of the same
form; the flint crystals are usually nee
dle-shaped, but the limestone crystals are
sometimes needle-shaped, sometimes club
shaped, sometimes sharp at one end and
knobbed at the other like little pins,
sometimes pronged or forked, and some
times they are made up of three or four
spines all of the same length. In some
kinds of Sponge the horny portion is so
loosely woven, and the spicule are so
scattered that the frame work is very
fragile, and crumbles on the slightest
pressure.


A living Sponge consists then of a
frame work, or skeleton, every portion
of which is covered by a soft, jelly-like
substance, which is in fact the united
bodies of an immense number of minute
animals. All over the. surface of the
Sponge are holes, or openings, varying in
size from the smallest pores to those
large enough to allow the insertion of a
finger. Channels run in every direction
! through the mass of Sponge, and connect
with the larger openings of the surface
and, when living, the Sponge is all the
time taking in water through the minute
| pores of the outside, and this water, after
having found its way to every part, flows
| along the channels and is forced out in
little jets at the large openings. Air and
food are brought in with the water which
enters at the pores, and waste matter is
carried out of the large holes. The tube
like structure of the Sponges, and the
absorbing and ejecting Of water seemed
to the people who lived long ago, so much
like the cellular structure of the lungs,
and the inhaling and exhaling of air,
that they gave to these curious objects
the name of Sea-Lungs.


Sponges increase by means of Young
these are first seen to be little yellowish
points in the substance of the parent
they increase in size, soon become de.
tached, and are carried out with the
streams Of water that flow from the
larger openings. The young Sponges, at
first, are not fixed to one spot like the
parent, but they are little soft oval
creatures which float and swim about in
the water, by means of the ella with
which one end of the body is furnished
/ After while they select, or seem to
select spot favorable to their growth
apparently stunning the light-become
attached, and grow gradually into shape
like that of the parent.


Sponges are useful to man in many
ways. and they have been of service to
him from very ancient times Aristotle
tells US that they were used to line the
brazen armor that the Greeks wore in
battle; for the Sponge placed between
i the armor and the skin served to render
less stunning the blows received. They
have also been used for hundreds OF
years for cleaning purposes. The ancient
Greeks and Romans used no table-cloths
but after meals washed their tables with
wet Sponges. The Sponge is of use to
artists in painting and to physicians and
surgeons in healing the sick and wound.
ed, and recently it has been used in the
manufacture of mattresses.


In some.of the islands of the warm seas
almost the whole occupation of the in
habltants is diving for Sponges which
grow in the waters around these islands
even the women and childaen learn to
dive. The men often descend far below
the surface of the water, thus exposing
themselves to the attacks of fierce, hun.
cry fishes, and with no weapons of de
tense except the knife which they carry
with them to be used in detaching the
Sponges from the rocks and from the
bottom of the sea.


But the story of the Sponges will MOI
be complete unless those are mentioned
which are found imbeded in the rocks o
our own and other countries. These are
called Fossil Sponges; they lived many
thousand years ago, when the places
where they now are found were covered
by the ocean, and where the rocks in
which they occur were soft sand and muo
which now forms the bottom of the ocean
and although three hundred or more
kinds of living Sponges are now known
none of these are exactly like the Sponge
which lived and grew in the old ocean Sc
many thousand years ago.


Almost every one has seen the minera
called flint, which was once so necessary
in gun locks, and which, before matches
were invented, was used with steel fol-
kindlng fire. Masses or nodules of this
mineral are found in chalk and in lime
stone, and strange as it seems, many O
these hard flint nodules were once living
Sponges growing in the sea- This is
known to be true from the fact that thin
slices Of flint have been examined by
means of the microscope, and they have
revealed the structure of the Sponge
and particles of Sponge not yet hardened
have been found inside the 1intI