and more efficient mechanism than that which
is contrived to propel Leviathans from
continent to continent. I am never tired of
watching the freaks of my merry neighbours,
the corkscrews; the more so as the game
they are playing is an insoluble puzzle. The
dullest looker-on continues to gaze at the
marvellous locomotion, whose means the eye
cannot perceive nor the mind divine.

Another fellow-inhabitant, which those who
behold it for the first time regard as a realised
incredibility—a thing they dare not describe
to their friends, for fear of being considered
long-bow drawers—is the walking-stick
worm (Vibrio bacillus). Myself thought I
was the victim of an optical delusion, till
repeated examination gave me convincing
proof of the presence, not of visionary phantoms,
but of real, moving material bodies. In
the field of the microscope, nothing is seen at
first; then, by looking sharp, catching a
favourable ray of oblique light, and hitting
the exact focus of your object-glass, multitudes
of living wands are seen traversing the
circle in all directions. They are stiff, with
a slightly undulatory motion, which causes a
slow steady progress in a straight line, either
backwards or forwards, for it seems all one
to them. There is no indication of head or
tail; they are all of the same apparent thickness,
but of very various lengths. No organs
are perceptible; but I fancy I can see the
symptoms of short articulations along the
whole of their length, as if a scolopendra or
forty-foot had caught a bad cold, which had
given it a stiff-neck and a lumbago in the
back. Of their food and generation nothing
is known. It is probable that if a walking-
stick worm is broken in two, the divided
portions become distinct individuals. It is
even possible that its reproduction may take
place by the separation and subsequent
growth of each several joint. But this is
only a guess at a mystery.

After one more remarkable denizen has
shown himself, we will take leave of our
little companions for the present. The nirnble-
thimble (to give it a familiar nick-name)
whose crystal body, furnished with a moveable
fringe at the end where a lady would
insert her finger, is an advanced stage of
the creature better known as Vorticella
infusionum—the little-eddy of infusions—and
every stagnant ditch is a cold infusion of
vegetable and animal matters. Some individuals
are longer and more cylindrical in
their shape than others, in which case they
look like glass pint-pots, without handles
to them. In its youth, we (at home) call
this Vorticella the night-cap animal, while it
is described in books as the bell-flower animal
and the bell animalcule. But, the
vivacious night-cap, instead of a tassel at the
top, is furnished with a long string which,
in the larger individuals, is visibly flat like
a ribbon. By the further end of the ribbon
it moors itself to some object of larger
dimensions, and commences fishing for its
prey, by vibrating the circle of bristles with
which the edge of the night-cap is fringed.
The action of this fringe,—a rapid waving
to and fro which the eye cannot follow
when at its plenitude of vigour,—causes an
irresistible whirlpool by which every minute
object within its influence is brought to the
yawning mouth of the cap. Whatever special
senses the night-cap may or may not
possess, it is gifted with extreme sensibility;
at the slightest provocation, or at no
provocation at all, it suddenly contracts the long
ribbon into a spiral screw, and is instantly
drawn, with a snatch and a spring, to its
retreat and its place of anchorage. It may
be compared, therefore, to a captive balloon,
wherein the aeronaut has the power of
instantly shortening the string that holds it
to the ground; or it may be likened to a
living paper-kite, which can fly under water
in whatever direction it pleases, at the end
of a string which is also itself alive.
Microscopic anatomists inform us that the string
or foot-stalk of the Vorticella contains no
trace of muscular fibre, but that its rapid
power of contraction and relaxation is due
to the contractibility of the tissue lining the
inside of the string, which is tubular, a
property with which it appears to be
specially endowed. At the same time that the
string is contracted into a screw, the fringe
of the night-cap is drawn tight close, and
it is converted into a globular bag. The
bell-animalcule takes alarm at the slightest
disturbance. If you put a drop of water
containing Vorticellas on your microscope
slide, you must often wait several seconds
before they will take courage to show
themselves after their forcible abduction from the
bottle in which you keep them. A somewhat
paradoxical fact is, that very young
bell-animalcules attach their stems to
substances which expose them to violent and
almost constant agitation; I have seen a
large little family settled on the tail of a
living tadpole, and another on the bivalve
shell of a Cypris, a lively little crustacean,
—the largest about the size of a mustard-
seed,—which is always restlessly rushing
through the water. However, should they
change their minds, they can at any time
lose hold of their turbulent quarters, and
swim away freely, dragging their tails behind
them, in search of some more comfortable
situation. By-and-by, a fringe of cilia or
bristles sprouts round the point whence the
ribbon proceeds; the ribbon is cast off, like
a tadpole's tail, as no longer wanted, and
the liberated night-cap takes to a roving
existence in the shape of the cylindrical
nimble-thimble, whom we have seen bustling
and jostling through crowded congregations
of Euglenas and whole companies of
corkscrew Spirillums.

And is this the whole list of our
unsuspected neighbours ? Ah, no! not by