The People's vindicator. [volume] (Natchitoches, La.) 1874-1883, 1880-10-30
The Life Of a Sponge.

a living marine sponge is not very easy ;
t'ut The fresh water sponges are common
enough, and will answer our purpose
just as we'll. They may be procured in
almost any slow.ilowing river. and are
adherent to twigs and similar objects
that have remained in the water for some
length of time. Take one of these
sponges, the smaller the better, and
place it in a glass vessel. A common
watch-glass will answer the purpose ad-
mirably. Presently distinct currents
will be perccp,iblc in the water, especi-
ally if 4 little carmine or indigo be dis
solved in it. Prus,ian blue is poisonous,
but the "blue" used by the laundress is
safe enough. Carmine, however, is, in
my opinion, better than any blue tint,
as it is prettier in general effect, and the
particles are SO transparent that they do
not become opaque when collected to-
gether. When the currents are fairly
established the magnifying glass will ex-
hibit wonderful phase Of animal life.
The whole of the surface Of the sponge
is covered with little prominences, hay
ING at the tip Of each tolerably large
aperture. Through this hole the colo,cd
water pours outward with q steady rush,
causing the currents which have made
themselves visible. But how did these
colored particles, which rush out with
such force, get into the sponge at all? A
more powerful lens will solve the prob
lem. The whole of the surface is stud
ded with innumerable little holes, pierre
inc through the gelatinous membrane,
and admitting the water into the inte.
rioro the sponge. A section oithe sponge
will show that, these little holes lead
into canals which travel in every direc-
ton through the substance Of the sponge
and finally lead to the large apcrturcs
through which the water is elected.
Every now and then the current will
stop, and all the tiny oritices are closed,
without evena mark to show where
they had been. Presently it begins
again, and then it will be seen that the
former orifices are not reopened, but
that fresh aperturcs are developed as
they are wanted. ~, - '...r a !,
Now we may ask ourselves how these
larger apertures are kept open, and to
answer the question we must call chem
istry to our aid. In some spongcs we
can use the blow-pipe; but as a general
rule some strong acid or alkali will de-.
stroy the whole of the animal matter.
If the. residuum be examined with the
microscope, q vast number Of CLASSY
spicules will be seen, varying in shape,
size and color with the kind Of sponge.
Some of them look exactly as ii they
were, made of pink and white sugar
candy, and all children to whom l have
shown them have expressed regret at
their inability to eat such tempting OBJ.
jects. t,E,J ,e.i7ai' - :.
Those of the ordinary sponge have
the most striking resemblance to the
''crow's-feet," or .'caltrops," which
were once used to impede the progress
Of cavalry. 1t is said that these spiculm
vary according to the substance on
which the sponge is fixed, as we'll as in
the species; but l have had no oppor.
tunity of testing this theory, and con.
tent myself with mentioning it. The
structure of the ordinary marine and
fresh-water sponges having been care
fully studied, biologists set about the
very necessary task Of classifying them.
Considering the nature of the subject,
this was no easy task, and almost as
many systems were promulgated as
there were biologists to write about
them. .,t