are nothing but plants very transparently
disguised under the semblance of animals!—
that they are only one of the "motile" forms
of a protean vegetable, Protococcus pluvialis,
the primitive rain-water grain, which has
the power of passing alternately from a still
to an active condition of life. If this be true,
we feel less indignant at the voracity of the
overgrown rotifer, who is only indulging in
a hearty meal of salad, instead of engulfing
whole shoals of innocent creatures; the insatiable
carnivore is tamed down to a grazer on
aquatic vegetation,—to the temper of a
hippopotamus, in short. But the anti-animal
theory for the Euglenas and others, though
supported by high authority, and very possibly
true, is still rejected by a considerable
body of obstinate sceptics who regard the
novel doctrine as heretical.

The second party of watermen who figure
on our stage—and the expression is scarcely
a metaphor; for the microscope has a stage as
well as a theatre; not to mention that all the
world's a stage, whereon all the insects and
animalcules are merely players, each playing
many part—our second party are akin to
the first. The Euglena's relation, who has
been alluded to, looks like a small ovate leaf
together with its footstalk, that had fallen
into the water, and had suddenly become
animated, swimming hither and thither with
a rolling and revolving motion. But instead of
being cylindrical and contractile, it is flat and
scale-like,—slightly twisted as a withered
leaf might be,—retaining its form after death,
and even after the loss of its internal green
colouring-matter. It has the bright red spot
towards its anterior extremity, which in this
case looks less like a real eye that that of its
fish-like cousin. Its thread of a whip, of
extremest fineness, is difficult to catch sight
of, even with the best of instruments. Our
present friend, named Phacus pleuronectes,
or side-swimming lentil, shows you how thin
he is when you look at him edgewise. He is
figured by Hogg as the flask-animalcule;
but it is as clear that he is nearly an empty
flask as it is doubtful whether we have the
slightest clue to his private memoirs. As he
is never observed to hold the least intercourse
or connection with his fellows; as no indication
of contractility has been perceived in the
disks, or globules, or vesicles, contained in his
interior; and as no food, foreign body, or
coloured substance has ever been seen to
enter what might be called his stomach; it is
impossible to form any clear idea, either of
the functions performed by his organisation,
or of the nature of his constitution as a living
individual. Perhaps he is not an animal at
all, though his long slender whipthong is
assumed to be a proof that he is.

If a prize were offered to the naturalist
who should invent a living creature, on the
condition of devising the most unthought-of
form for an animal intended to inhabit a
liquid and a muddy medium, he would
scarcely have the hardihood to propose such
a strange, yet such a charming little monster
as my pet, whom I call the corkscrew-worm,
but who was christened by Ehrenberg,
Spirillum undula; spirillum meaning a goat's
beard, the name is not inapt. There are
several Spirillums; namely, undula, volutans,
plicatile, and tenue. Future observers,
perhaps, may find reason to consider them as
different stages of the same species. To
form some idea of what they are like, without
actually seeing them, cut off a ringlet of
stiff-curling hair that makes two or three
turns; endow each hair with the rigidity of
iron-wire ; separate them; animate them;
and set them darting through the water,
screw-like, in all directions, with a velocity
which the eye can scarcely follow, and you
have the Spirillum volutans magnified. If
there were any moderate-sized existing shellfish,
say six inches long and half-an-inch
thick, with the same form, proportions, and
mode of locomotion as the Spirillum has, it
would be a most formidable submarine
projectile for a ship's bottom to encounter;
especially as these water-rockets fly, not
singly, but in multitudinous coveys. They
would be enough to sink another Russian
fleet. The Spirillums are of equal thickness
at each end. There is no perceptible evidence
of head or tail, or other appreciable organisation.
In fact, they appear to have no real
tail, but to be double-headed serpents twisted
into an inflexible curve; they move
backwards or forwards, therefore, with equal
ease; they have no difficulty in wheeling
about or putting themselves in a position
perpendicular to the side of glass on which
they are swimming. They run races together,
as it were, and stop from time to
time to take breath, or water; but by what
mechanical agency all this is effected, we
must be content to remain in ignorance till
the next grand improvement in microscopes
takes place. Spirillums can neither contract
their screw closer, nor extend themselves
into a straight line; they remain as rigid
after death as they were during life; nor can
any division of parts or articulations (to be
relied on) be seen under the highest magnifiers.
They look like black, opaque, or
transparent wavy lines, according as they are
a little without or within the focus. All
that can be received with certainty is, that
their screw-like shell, instead of being round
like a wire, is flat, like the blade of a knife,
with the thickest part of the blade next to the
axis of the screw. The inventor of the screw-
propeller for steamboats, therefore, had been
forestalled in his patent long ago. Here
is a despised, I may say an unknown
little animal, which flashes through the
water at an incredible rate; who screws
himself deep into the mud when bad weather
comes, and who screws himself out again as
easily when fine weather returns, by simpler