The Invisible World
Revealed by the Microscope
Thoughts on Animalcules
A fact not less startling than would be the realisation of the
imaginings of Shakespeare and of Milton, or of the speculations of
Locke and of Bacon, admits of easy demonstration, namely, that the
air, the earth, and the waters teem with numberless myriads of
creatures, which are as unknown and as unapproachable to the great
mass of mankind, as are the inhabitants of another planet. It may,
indeed, be questioned, whether, if the telescope could bring within
the reach of our observation the living things that dwell in the
worlds around us, life would be there displayed in forms more
diversified, in organisms more marvellous, under conditions more
unlike those in which animal existence appears to our unassisted
senses, than may be discovered in the leaves of every forest, in the
flowers of every garden, and in the waters of every rivulet, by that
noblest instrument of natural philosophy, the Microscope.
Larva of the Common Gnat.
- The body and head of the larva (magnified).
- The respiratory apparatus, situated in the tail.
- Natural size.
To an intelligent person, who has previously obtained a general
idea of the nature of the Objects about to be submitted to his
inspection, a group of living animalcules, seen under a powerful
microscope for the first time, presents a scene of extraordinary
interest, and never fails to call forth an expression of amazement
and admiration. This statement admits of an easy illustration: for
example, from some water containing aquatic plants, collected from a
pond on Clapham Common, I select a small twig, to which are attached
a few delicate flakes, apparently of slime or jelly; some minute
fibres, standing erect here and there on the twig, are also dimly
visible to the naked eye. This twig, with a drop or two of the water,
we will put between two thin plates of glass, and place under the
field of view of a microscope, having lenses that magnify the image
of an object 200 times in linear dimensions.
Upon looking through the instrument, we find the fluid swarming
with animals of various shapes and magnitudes. Some are darting
through the water with great rapidity, while others are pursuing and
devouring creatures more infinitesimal than themselves. Many are
attached to the twig by long delicate threads, several have their
bodies inclosed in a transparent tube, from one end of which the
animal partly protrudes and then recedes, while others are covered by
an elegant shell or case. The minutest kinds, many of which are so
small that millions might be contained in a single drop of water,
appear like mere animated globules, free, single, and of various
colours, sporting about in every direction. Numerous species resemble
pearly or opaline cups or vases, fringed round the margin with
delicate fibres, that are in constant oscillation. Some of these are
attached by spiral tendrils; others are united by a slender stem to
one common trunk, appearing like a bunch of hare-bells; others are of
a globular form, and grouped together in a definite pattern, on a
tabular or spherical membranous case, for a certain period of their
existence, and ultimately become detached and locomotive, while many
are permanently clustered together, and die if separated from the
parent mass. They have no organs of progressive motion, similar to
those of beasts, birds, or fishes; and though many species are
destitute of eyes, yet possess an accurate perception of the presence
of other bodies, and pursue and capture their prey with unerring
Thoughts on Animalcules.
Hair, Greatly Magnified.
- Hairs of the Bat.
- Of the Mole.
- Of the Mouse.