The Formation of Vegetable Mould Through the Action of Worms: With Observations on Their Habits — John Shaqi
The Formation of Vegetable Mould Through the Action of Worms: With Observations on Their HabitsDarwin, Charles
Science
The Formation of Vegetable Mould Through the Action of Worms: With Observations on Their Habits
Darwin, Charles
Earthworms; Humification; Soils
In the first place 227 withered leaves of various kinds, mostly of
English plants, were pulled out of worm-burrows in several places. Of
these, 181 had been drawn into the burrows by or near their tips, so that
the foot-stalk projected nearly upright from the mouth of the burrow; 20
had been drawn in by their bases, and in this case the tips projected
from the burrows; and 26 had been seized near the middle, so that these
had been drawn in transversely and were much crumpled. Therefore 80 per
cent. (always using the nearest whole number) had been drawn in by the
tip, 9 per cent. by the base or foot-stalk, and 11 per cent. transversely
or by the middle. This alone is almost sufficient to show that chance
does not determine the manner in which leaves are dragged into the
burrows.
Of the above 227 leaves, 70 consisted of the fallen leaves of the common
lime-tree, which is almost certainly not a native of England. These
leaves are much acuminated towards the tip, and are very broad at the
base with a well-developed foot-stalk. They are thin and quite flexible
when half-withered. Of the 70, 79 per cent. had been drawn in by or near
the tip; 4 per cent. by or near the base; and 17 per cent. transversely
or by the middle. These proportions agree very closely, as far as the
tip is concerned, with those before given. But the percentage drawn in
by the base is smaller, which may be attributed to the breadth of the
basal part of the blade. We here, also, see that the presence of a
foot-stalk, which it might have been expected would have tempted the
worms as a convenient handle, has little or no influence in determining
the manner in which lime leaves are dragged into the burrows. The
considerable proportion, viz., 17 per cent., drawn in more or less
transversely depends no doubt on the flexibility of these half-decayed
leaves. The fact of so many having been drawn in by the middle, and of
some few having been drawn in by the base, renders it improbable that the
worms first tried to draw in most of the leaves by one or both of these
methods, and that they afterwards drew in 79 per cent. by their tips; for
it is clear that they would not have failed in drawing them in by the
base or middle.
Public-domain text, read in full here on John Shaqi.
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