buried to a
considerable depth beneath accumulated castings lie dormant, until at
some future time they are accidentally uncovered and germinate.

[Illustration: A WORM CASTING FROM SOUTH INDIA. (Natural Size.)]

Worms are poorly provided with sense-organs, for they cannot be said
to see, although they can just distinguish between light and darkness;
they are completely deaf, and have only a feeble power of smell; the
sense of touch alone is well developed. They can, therefore, learn
little about the outside world, and it is surprising that they should
exhibit some skill in lining their burrows with their castings and
with leaves, and in the case of some species in piling up their
castings into tower-like constructions. But it is far more surprising
that they should apparently exhibit some degree of intelligence
instead of a mere blind, instinctive impulse, in their manner of
plugging up the mouths of their burrows. They act in nearly the same
manner as would a man, who had to close a cylindrical tube with
different kinds of leaves, petioles, triangles of paper, etc., for
they commonly seize such objects by their pointed ends. But with thin
objects a certain number are drawn in by their broader ends. They do
not act in the same unvarying manner in all cases, as do most of the
lower animals; for instance, they do not drag in leaves by their
foot-stalks, unless the basil part of the blade is as narrow as the
apex, or narrower than it.

* * * * *

When we behold a wide, turf-covered expanse, we should remember that
its smoothness, on which so much of its beauty depends, is mainly due
to all the inequalities having been slowly levelled by worms. It is a
marvellous reflection that the whole of the superficial mould over any
such expanse has passed, and will again pass, every few years through
the bodies of worms. The plough is one of the most ancient and most
valuable of man's inventions; but long before he existed the land was
in fact regularly ploughed, and, still continues to be thus ploughed
by earth-worms. It may be doubted whether there are many other animals
which have played so important a part in the history of the world, as
have these lowly organized creatures. Some other animals, however,
still more lowly organized, namely, corals, have done far more
conspicuous work in having constructed innumerable reefs and islands
in the great oceans; but these are almost confined to the trop