WHAT IS A SPONGE?
Before entering upon the great subject of water and ice--two of the most
tremendous factors in world-building--let us consider a small matter, so
far as its permanent effects are concerned, yet one which enters largely
into the comfort and health of mankind, and which, though an animal, may
be discussed where it belongs--under "Water."
There are few things more familiar about the ordinary household than a
piece of sponge, and yet, perhaps, there are but few things about which
there is so little known. The sponge had been in use many, many years
before it was given a place in either the animal or vegetable kingdom.
The casual observer, because he saw it attached to a rock, jumped to the
conclusion that it was of vegetable origin. But after being kicked back
and forth, so to speak, from one kingdom to the other, even by what are
called well-educated people, it has finally been received into the
family of animals; a dignity in which the sponge itself seems to take
but little interest.
The sponge is found in the bottom of the sea; at no very great depth,
however. It is usually attached to a rock or some other substance and it
is due to this fact chiefly that it has been classed as a vegetable. At
least one scientist has attempted to give it a place between the two
kingdoms, but this only adds confusion without giving any satisfactory
explanation of its origin. It seems to belong to a very low order of
animal life. It breathes water instead of air, but probably, like many
other water animals, it absorbs the oxygen from the air which is more or
less contained in the water. There is a process of oxidation going on
within the sponge in a manner somewhat as we find it in ordinary animal
life, and like the animal it expels carbon dioxide. All this, however,
is carried on apparently without any lungs or any digestive organs, or
in fact any of the organs that are common to the animals of the higher
order. The sponge, however, as we see it in our bathrooms, is only the
framework, bony structure, or skeleton of the animal.
The sponge is exceedingly porous and readily absorbs water or any fluid
by the well-known process of capillary attraction. The sponge fiber is
very tough and is not like anything known to exist in the vegetable
kingdom. The substance analyzes almost the same as ordinary silk, which
all know is an animal product. If we burn a piece of sponge it exhibits
very much the same phenomena as the burning of hair or wool, and the
smell is very much the same.
The structure of a piece of sponge when examined under a microscope is a
wonderfully complicated fabric. Under the microscope it shows a network
of interlacing filaments running in every direction in a system of
curved lines intersecting and interlacing with each other in a manner to
leave capillary openings.
It is a wonderful structure, and one that a mechanical engineer could
get many valuable lessons from. It will stand a strain in one direction
as well as another. There are no special laminations or lines of
cleavage; it is very resilient or elastic, and readily yields to
pressure, but as readily comes back to its normal position when the
pressure is relieved. If we examine the body of a sponge we shall notice
that there are occasional large openings into it, but everywhere
surrounded by smaller ones. If we should capture a live sponge and place
it in an aquarium with sea water, where we could study it, we should
find a circulation constantly going on, and that water was constantly
sucked in at the smaller openings all over the outside of the sponge and
as continuously ejected from the large openings. This process
constitutes what corresponds in the higher order of animals to both
respiration and blood circulation, combined. The sponge feeds upon
substances that are gathered up from the sea water, and breathes the air
contained in the same, so that it breathes, eats, and drinks through the
same set of organs.
When we first capture a live sponge from the sea it has a slimy, dirty
appearance, and is very heavy. The sponge is found to be filled with a
glutinous substance that is the fleshy part of the animal. It is very
soft and jelly-like, and after the sponge is dead it is readily squeezed
out, by a process which is called "taking the milk out," which leaves
simply the skeleton, the only useful part as an article of commerce.
This fleshy substance, in life, has somewhat the appearance and
composition of the white of an egg.
The mechanical process by which the sponge takes its nourishment is
exceedingly interesting. There are small globe-shaped cells with
openings through them that are lined with little hairlike projections
that move in such a manner as to suck the water in at one side of the
cell and push it out at the other. These little fibers are technically
called "cilia." We might describe them as little suction pumps that are
located at many points in the sponge, all acting conjointly to produce a
circulation through the finer openings or capillary vessels and finally
discharging into the larger chambers which carry off the residue. If we
should analyze the water as it is sucked into the sponge and that which
issues from it through the larger openings, we should find a difference
between the two. The expelled water would contain more or less carbon
dioxide.
There are many different varieties of sponge, and, while they all
possess certain characteristics in common, they are still very different
in many respects. Some of them are large and coarse, while others are
exceedingly soft and velvety. What is called a single sponge is a colony
of animals rather than a single animal; at least they are so regarded by
zooelogists. This can hardly be true if we regard the sponge itself as a
part of the animal. If the sponge is simply regarded as the house in
which the animal lives then it becomes a great tenement with numerous
occupants. But it is a tenement upon which the life of the sponge
depends, and is a part of it.
The sponge could not breathe without the fibrous structure in the cells
containing the machinery for producing the circulation. It will be seen
that the sponge, while it is an animal, is of the very simplest variety,
so far as its organs are concerned. True, its framework is very
complicated, but the organs for sustaining the life of the animal are
the simplest possible. The little self-acting pumps pull the water into
the sponge through the smaller openings, where it appropriates the food
substance from the water and where a chemical action takes place which
builds up the fleshy substance of the animal, and then expels the
residue which is not needed to support its life.
Simple as it is, however, as a mechanical structure, the life and growth
of the sponge is as mysterious as that of the most highly organized
animal or even the soul of man. We can study out the structure of a
plant or animal; we can analyze it and tell what are the elements of
which it is composed; we can describe the mechanical operations that are
carried on and the chemical combinations that take place, but no man has
ever yet solved the mystery of life, even in the lowest form--whether
animal or vegetable.
The sponge, whether considered as a single or compound animal, has the
power to reproduce itself, and here the mystery of life is as much
hidden as it is in God's highest creation. It has been stated that every
sponge contains a large number of separate cells which carry on the
operation of circulation and respiration, and may be likened to the
heart and lungs of an animal of a higher creation. Zooelogists claim that
each one of these cells represents a separate animal, living in a common
structure. However this may be, it is an interesting fact that the
sponge has the power of secreting ova that grow in large numbers in
little sacks until they have reached a certain stage of progress, when
they are expelled from the mother sponge and turned adrift in the great
ocean to struggle for their own existence. These eggs do not differ much
in their structure and composition from an ordinary hen's egg, except
that there is no shell, only a skin provided with little fibers called
cilia, that project from it, and by the movement of these the embryo
sponge is able to propel itself through the water. It thus lives until
it has reached a certain stage of development, when it seeks out a
pebble or rock, to which it attaches itself at one end--preparation for
which has been made by its peculiar structure during its life when it
was free to float around through the water. It is now a prisoner and
chained to the rock it has selected for the foundation of its home.
Having no longer any use for the little cilia, which enabled it to swim
through the water, it now loses them. Here is a beautiful illustration
of how nature provides for the necessities of the smallest things, and
how when the necessity that demanded a certain condition passes by the
condition passes with it. The embryo begins to show a fibrous
development, which is the beginning of the framework of a new sponge.
Evolution goes on, every step of which is as mysterious as a miracle,
until the growing thing is a full-grown sponge, equipped with the means
for respiration, circulation, feeding, digestion, and reproduction.
Sponges grow in the bottom of the sea at different depths. They are
obtained by divers who make a business of gathering them. The best
sponges are called the Turkish sponge, which are very soft and velvety,
and may be bleached until they are nearly white by subjecting them to
the action of certain acids. The divers become very expert, but they do
not have the modern equipments of a diving suit. The Syrian divers in
the Mediterranean go down naked with a rope attached to their waists and
a stone attached to the rope to cause them to sink, together with a bag
for carrying the sponges. They have trained themselves until they can
remain under water from a minute to a minute and a half, and in that
time can gather from one to three dozen sponges. The ordinary depth to
which they descend is from eight to twelve fathoms. But a very expert
diver will go down as far as forty fathoms. The better class of sponges
are said to grow in the deeper waters. The coarse inferior sponges are
called the Bahama sponge. This sponge is of a peculiar shape, growing
more like a brush, with long bristly fiber.
The trade in sponges is quite large. The consumption in Great Britain
alone amounts to about $1,000,000 per annum.
The sponge as an animal possesses many advantages over his more
aristocratic neighbor, man. He breathes but he has no lungs, and
therefore cannot have pneumonia. He digests his food, but he has no
stomach, and therefore never has dyspepsia, gastritis, or any of the
many ailments that belong to that much abused organ. He has no
intestines, and therefore cannot have appendicitis or Asiatic cholera or
any of the long train of diseases incident to those complicated organs.
He has no nervous system--oh, happy sponge!--therefore he cannot have
nervous prostration, hysteria, or epilepsy. He has no use for doctors,
and therefore has no unpleasant discussions with his neighbors about the
relative merits of the different schools of medicine. If he has any
predilections in the way of "pathies" we should say that he is a
hydropath. While he is a great drinker, he is not at all convivial--he
drinks only water, and takes that in solitary silence. He sows all his
wild oats when he is very young, while he has the freedom to roam at
will. He soon tires of this, however, for he selects the rock that is to
be the foundation of his future home and there settles down for life,
"wrapt in the solitude of his own originality." He is not troubled with
wars or rumors of wars. His eyes are never startled or his nerves shaken
by the scare headlines of yellow journalism. The one sensation of his
life, if sensation he ever has, is when a great ugly creature of some
Oriental clime comes down to his home and tears him away from his native
rock, carries him to the surface, and there literally "squeezes the life
out of him." He finally dies of the "grip," and here he sinks to the
level of his more aristocratic neighbor.
But there is another side to our philosophy. If the sponge is exempt
from all these ills that we have enumerated it is because he is
incapable of suffering and is therefore incapable of enjoyment. Those
beings that have the ability to suffer most have also the ability to
enjoy most. The higher the type of civilization the greater
possibilities it offers for real enjoyment--also for real misery. This
being true, it should be the aim of highly civilized people to eliminate
as far as possible those things that make for misery, and cultivate
those things that make for happiness in the highest and best sense.