Curiosities of Animal Life [pp. 232-239]

Curiosities of Animal Ltife..
which we call digestion. You may
turn a hydra inside out and it will
get along just as well as it did before,
and swallow its prey with just as good
an appetite. The French naturalist
Trembley was the first to notice this
remarkable fact. With the blunt end
of a small needle he pushed the bottom of the sack through the body and
out at the mouth, just as you would
invert a stocking. He found that the
animal righted itself as soon as it was
left alone; so he repeated the operation, and this time made use of persuasion, in the form of a bristle run
crosswise through the body, to induce
the victim to remain inside out. In
the course of a few days its interior
and exterior departments were thoroughly reorganized, and it ate as if
nothing had happened. Trembley
next undertook to engraft one individual upon another! For this purpose
he crammed the tail of one deep down
into the cavity of another, and, in order
to hold them in their position, stuck a
bristle through both. What was his
surprise to find them, some hours
afterward, still spitted upon the bristle, but hanging side by side instead of
one within the other! How they had
got into such a position he could not
imagine. He arranged another pair,
and on watching them the mystery
was solved. The inner one first drew
up its tail and pushed it out through
the hole in the outer one's side where
the bristle entered. Then it pulled
its head out after the tail, and sliding
along the spit completely freed itself
from its companion. This it repeated as often as the experiment was
tried in that way. It then occurred
to M. Trembley that if the inner
hydra were turned inside out. so as to
bring the stomachs of the two animals
in contact, union would take place
more readily; and so it provedt The
little creatures seemed much pleased
with the arrangement, and made no
attempt to escape. In a short time
they were united as one body, and enjoyed their food in common.
It was perhaps only natural to ex
peet that animals which care so little
about their individuality that two specimens can be turned into one, would
be equally ready to multiply themselves by the simple process of being
cut to pieces. In other words, you
may make one lhydra out of two, or
two out of one, just as you please.
M. Trembley divided them in every
conceivable manner. He cut them
in two, and, instead of dying one half
shot out a new head and the other
developed a new tail. Ile sliced them
into thin rings, and each slice swam
away, got itself a set of tentacles,
and grew into a perfectly formed individual. He split them into thin
longitudinal strips, and each strip reproduced what was wanting to give it
a complete body. Some he split only
part way down from the mouth, and
the result was a hydra, like the fabled
monster, with many heads. The famous cat with nine lives is nothing
to these little zoophytes. They seem
sublimely.indifferent not only to the
most fearful wounds, but even to disease and, we are tempted to add, decomposition itself. A part of the body
decays, and the hydra simply drops it
off, like a worn-out garment, and lives
on as if it had lost nothing.
If it can do all this, we need\ not
wonder that it can reproduce its kind
by budding. Indeed, after we have
seen a living creature split itself up
into a dozen distinct individuals any
other process of generation must seem
tame by comparison. At certain seasons of the year very few hydras can be
found which have not one, two, or three
young ones growing out of their bodies.
The budding begins in the form of a
simple bulging from the side of the
parent, something like a wart. This
is gradually elongated, and after a time
tentacles sprout from the free end, and
a mouth is formed. The young is
now in a condition to seek its own
prey. Its independence is finally accomplished by a constriction of the
base of the new body at the point
where it is attached to the old stock,
until finally it cuts itself off. Before
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