Were we in search of design in nature, or an illustration of the wonders
of the microscope, no better example could be suggested to us than the
form and structure of a fly. Its tiny body is even more wonderful than
the body of a man. Take, for instance, its marvellous power of walking.
It can walk anywhere or anyhow, setting every principle of gravitation
at defiance by promenading head downwards along the ceiling, or skipping
up and down the glittering window-pane, pursuing objects that to us are
quite invisible. How is the feat accomplished? What peculiarity has its
little foot that the daring acrobat can keep itself suspended in that
dizzy and foolhardy position? The microscope gives us the answer. The
foot consists of two pads covered with innumerable short hairs, and
these hairs are hollow, having trumpet-shaped mouths filled with gum.
This gum becomes so hard when exposed to the air, that it will not
dissolve in water, so that at every step the fly glues itself to the
ceiling, and there it would remain unless it knew how to lift its feet.
It lifts them in a slanting direction while the gum is still moist, just
as you would remove a moist postage stamp by taking hold of one corner
and gently drawing it back. And think of the creature's eye. It can
observe everything in four-fifths of the circle round it, so that to
compete with a fly we would require two more pair of eyes, one at the
side and another at the back of our head. But in no sense can we
compete with these aerial nomads. They have three sets of brain instead
of one. They have wings, which we have not. They have six legs instead
of two; and their proboscis or trunk is as far beyond that of an
elephant "as a railway engine is beyond a wheelbarrow."
As seen under a powerful microscope, the structure of a common fly is a
perfect marvel of design, and it may well excite our curiosity and call
forth our admiration. It points us to the greatness and wisdom of Him
whose works are as perfect in the tiniest insect as in the brightest
star, whose power is as manifest in the humblest sea-shell as in the
huge leviathan that makes the ocean its playground--
"All are but parts of one stupendous whole,
Whose body Nature is, and God the soul."