The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1895-12-14
Earthworms as Workers.
c. +. Marshall. NJ D., B. Sc, F. X. c. s. in
knowledge.


man and heedlessly uodden under foot,
fulfils part in nature that would seem
incredible but for the facts revealed by the
patient and long continued researches OF
Darwin. Worms, says Darwin. ''have
PLAYED Il more important part IN the hlsto-
~ of the world than most persons would
at first suppose. Let us follow Darwin
and see how this apparently insignificant
creature has changed the face of nature.
We will first consider the habits and mode
of life of the earthwom. As every one
knows. the worms live III burrows in the
superficial layer of the ground. They can
live anywhere in layer OF earth provided
it retains moisture. dry air being fatal to
them. They can un the other hand. eN-
list submerged in water for several months
They live chiefly in the superficial mould
less than foot below the surface. but IN
long. continued dry weather and IN very
cold seasons they may burrow to 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 push
ing away the earth, but chiefly by the
earth being swallowed. Large quantities
of earth are swallowed by the worms for
the sake Of the decomposin@ vegetable
matter contained in it. on which they feed.
The earth thus swallowed is voided III spiral
heaps. forming the worm castings. In
this way the worm obtains food and at the
same time excayates 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 noe
turnal in habit. remaining, as Il rule. IN
the burrows during the day and coming
out to feed at night.
The leaves dragged into the burrows are
moistened by fluid secreted by the worm,
Of digestive nature, and the food is thus
partly digested before being swallowed.
The digestive fluid of the earthworm re-
sembles the pancreatic juice of higher ant
mails, and only acts when alkaline. Va
rious acids are produced by decaying vege
table matter. and similar changes occur in
the leaves swallowed by worms Now if
some of this acid was not neutrallzed. dl-
gestion could not take place, because the
digestive fluid is alkaline. This is avoided
L Il e
the calciferous glands, opening into the
elementary canal These glands secrete
carbonate of lime. which neutralizes the
acids generated in the decaying leaves.
The earthworm has no eyes, but is at
fected by strong light if exposed to it for
some time 1t has no sense Of hearing.
but is sentitive to the vibrations Of sound
The whole body is sensitive to touch.
There appears to be some sense Of smell
but this is limited to certain articles of
food, which are Dissolved by the worm when
buried in earth, in preference to other
bodies not relished. The worm appears
10 have some degree of intelligence from the
way in which it draws the leaves into its
burrows, always Judging which is the best
end to draw them in by. This is remark
able in so lowly organized an animal, being
Il degree of intelligence not possessed by
many animals of more complex organlza
zion. For instance, the ant can often be
seen dragging objects along transversely.
instead of taking them the easiest way.
As we have seen, vast quantities Of
earth are continually being passed through
the bodies OF worms and voided on the
surface as castings. When it is stated
that the number of worms in an acre Of ordi
nary land, suitable for them to live in, is
30, 600, we can imagine the great effect
which they must have on the soil. They
are in fact, continually ploughing 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 gizzard which is the main factor
in triturating the soil, and it is aided by
small stones swallowed with this earth
which act as millstones The earth is thus
continually passing through the mill formed
bv the gizzards of worms, and is reduced
to fine mould Again, from the collapsing
of the old burrows the mould is in constant
slow movement, and its particles rubbed
together. Fresh surfaces are thus exposed
to the action of the carbonic acid In the
soil and to the human acids, agents which
act in the destruction of stones and rocks.
Moreover, the acid produced in the diges-
tive tract of the worms is not all neutral
lied. for the castings have an acid reac-
ton. and this acid acts further in the dis
Indignation of rocks.
Thus all the mould covering ii field
passes every few years through the bodies
of worms, and the same fragments are
probably swallowed and brought to the sur
face many times over in the course Of cen
turtles. Changes are also produced in the
lopes of hills by the flowing down of moist
castings and the rolling down Of dry ones
thus reducing the slope of the hills by &C
cumulations at the bottom. The casting
are also blown repeatedly in one direction
by the prevalent winds, Now as laye
of earth one-fifth of an inch thick, or tel
tons by weight. has been calculated IL
many places to be brought annually to tn
surface per acre, if only a small part o
this flows down every inclined surface, o
is blown repeatedly by the wind in on
direction, it is easy to see that grea
change may be produced in the surface 0
the land in the course of ages.
In consequence of the immense amour
of earth continually being brought to tn
surface by worms, it is not difficult to nn
derstand how objects such as stones, rocks
&c, lying on the surface, will in course {
time become gradually buried in the grount
The worms, undermining the stones, brin
up the earth to the surface, and so rail-
the ground round the edge of the stone ii
the latter SIMS and is eventually buried