The National tribune., 1881-12-24

To name a plant, or an insect, Or a bird, or a
quadruped rightly, is one step towards an aceur-
ate knowledge Of it, though it is not the knowl-
edge itself 1t is the means, and not the end in
natural history as in every other science.
DARWIN ON EARTH-WoRMs.- -" Worms pre-
pare the ground in an excellent manner for the
growth of fbrous-rooted plants and for seedlings
OF all kinds. They periodically expose the mould
to the air, and sitt it so that no stones larger
than the particles which they can swallow are
left in it. They mingle the whole intimately
together, like gardener who prepares fine soil
for his choicest plants. In this state it is well
fitted to retain moisture and to absorb all sOlu-
able substances we'll as for the process of nitri
fcatiop. The bones of dead animals the harder
parts of insects, the shells of land molluscs
leaves, twigs, &c, are before long all buried be-
meath the accumulated castings of worms, and
are thus brought in a more or less decayed state
within reach Of the roots of planus. Worms
likewise drag an infinite number OF dead leaves
and other parts OF plants into their burrows
partly for the sake of plugging them up and
partly as food.
The leaves which are dragged into the bur
rows as tood after being torn into the finest
shreds partially digested, and saturated with
the intestinal and urinary secretions are COM
mingled with much earth. This earth forms the
dark-colOred, rich humus which almost every
where covers the surface of the land with a fairly
well-detined layer or mantle. Won Hensen placed
two worms in q vessel IS inches in diameter
which was filed with sand, on which fallen leaves
We're strewed, and these were soon dragged into
their burrows to depth of ) inches After about
six weeks an almost uniform layer Of sand
inches IN thickness was converted into humus
by having passed through the alimentary canals
OF these two worms 1t is believed by some per
sons that wOrm-burrows which often penetrate
the ground almost perpeudicularIy to a depth of 5
or feet, materially aid in its drainage, notwith-
standing that the viscid castings piled over the
mouths OF the burrows prevent or check the rain
water from directly entering They allow the
air to penetrate deeply into the ground. They
also greatly facilitate the downward passage of
roots of moderate size; and these will be nourished
oy the humus with which the burrows are lined |
Many seeds owe their germinaton to having been
covered by castings; and others, buried to a con-
siderable depth beneath accumulated castings lie
dormant, until at some future time they are ac-
;identally uncovered and germinate.
Worms are poorly provided with sense
organs, for they cannot be said to see. although |
hey can just distinguish between light and |
darkness; they are completely deaf and have
,nly feeble power of smell; the sense of touch
llone is well developed They can therefore
earn little of the outside world and it is surprs
ng that they should exhibit some skill in lining
heir burrows with their castings and with leaves,
md in the case of some species in piling up their
astings into tower-like constructions But # is
ar more surprising that they should apparently
Exhibit some degree of intelligence instead of
mere blind instructive impulse, in their manner
If plugging up the mouths of their burrows.
they act In nearly the same way as would a
nan who had to close a cylindrical tube with
ifferent kinds of leaves, petioles, triansles of
'aper, &c, for they commonly seize such objects
y their pointed ends. But with thin obie cts a
ertain number are drawn in by their broader
nds They do not act in the same unvaryinc
laGner in all cases, as do most OF the lower ami
lals; for instance, they do not drag in leaves by
heir tootstalks unless the basal part Of the blade
as narrow as the apex, or narrower than it is
When We behold wide, turf covered ex-
anse, We should remembe that it's snoothness
u which so much ofits beauty depends, is mainly