The Press., 1906-07-04
WORK OF THE WORMS
THEIR IMPORTANT PART IN THE HIS
TORY OF THE WORLD.

Preserved by Them - Some of the
Pecul1ar1tles of the Senses of the
EarthwOrms.
The common earthworm, despised by
man and heedlessly trodden underfoot,
fulhlls a part In nature that would
seem incredible but for the facts re-
vealed by the patient and long cQntin-
ued researches of Darwin. Worms"
says Darwin, ''have played more i'm.
portant part in the history Of the world
than most persons would at first sup
pose" Let us follow Darwin and see
how this apparently insignificant crea-
ture has changed the face Of nature.
We will first consider the habits and
mode Of life Of the earthworm. As
every one knows, the worms live In
burrows In the superficial layer Of the
ground. They can live anywhere in
a layer Of earth, provided it retains
moisture, dry air being fatal to them.
They can, on the other hand, exist sub
merged in water for several months.
They live chiefly in the superficial
mold less than a foot below the sur!
face, but in long continued dry wealth
er and in very cold seasons they may
burrow to a depth Of eight feet. The
burrows are lined by thin layer OF
earth, voided by the worms, and end
| in small chambers in which they can
turn around.
The burrows are formed partly by
pushing away the earth, but chiefly by
the earth being swallowed. Large
quantities of earth are swallowed by
the worms for the sake Of the decOm-
posing vegetable matter contained IN
it. on which they feed. The earth
thus swallowed Is voided in spiral
heaps, forming the worm castings. In
this case the worm obtains food and at
the same time excavates its burrows.
In addition to the food thus obtained
half decayed leaves are dragged into
the burrows, mainly for food, but also
to plug the mouths of the burrows for
the sake Of protection. Worms are
also fond of meat, especially fat. They
will also eat the dead bodies of their
relatives. They are nocturnal in hab-
it, remaining, as rule, in the burrows
during the day and coming out to feed
at night.
The earthworm has no eyes, but is
affected by strong light if exposed to it
for some time. 1t has no sense Of
hearing, but is sensitive to the vibra-
sensitive to touch. There appears to
be some sense Of smell, but this is linn
tied to certain articles Of food, which
are discovered by the worm when
buried in earth, in preference to other
bodies not relished. The worm appears
to have some degree of intelligence
from the way in which it draws the
leaves into it's burrows, always judg-
ing which is the best end to draw them
in by. This is remarkable in so lOwly
organized an animal, being a degree of
intelligence not possessed by many ami
mails Of more complex organization.
For instance, the ant can often be seen
dragging objects along traversely in
stead Of taking them the easiest way.
AS we have seen, vast quantities Of
earth are continually being passed
through the bodies Of worms and void
ed on the surface as castings. When
in an acre of ordinary land suitable for
them to live in is $1,000 we can imag-
inc the great effect which they must
have on the soil.
They are, in fact, continually blowing
the land. At one part Of the alimentary
canal Of the worm is giZzard, or hard
muscular organ, capable Of grinding
food into fine particles. 1t is this giZ-
Yard which is the main factor In tritu-
rating the soil, and it is aided by small
stones swallowed with the earth, which
act as millstones.
In consequence Of the immense
amount Of earth continually being
brought to the surface by worms it Is
not difficult to understand how objects,
such as stones, rocks, etc., lying on the
surface will in course of time become
gradually buried in the ground. Owing
to the burial Of stones and other objects
by the action of worms ancient monu-
ments, portions Of Roman villas and
other objects Of antiquity have been
preserved. These have been gradually
buried by the worms and SO preserved
from the destructive effect Of rain and
wind. Many Roman remains were
studied by Darwin and traces Of the
action Of worms found, to which action
their preservation was mainly due. The
sinking of the foundations of old build
lngs is due to the action Of worms, and
no building is safe from this unless the
foundations are laid lower than the
level at which the worms can work
namely, about eight feet below the sur
face.
Another useful effect produced by
worms is the preparation Of the soil for
the growth of seedlings. By their agen-
cy the soil is periodically sifted and ex-
posed to the air and in this way is able
to retain moisture and absorb soluble
substances of use for the nutrition Of
plants.