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
The petioles of _Robinia pseudo-acacia_ vary from 4 or 5 to nearly 12
inches in length; they are thick close to the base before the softer
parts have rotted off, and taper much towards the upper end. They are so
flexible that I have seen some few doubled up and thus drawn into the
burrows of worms. Unfortunately these petioles were not examined until
February, by which time the softer parts had completely rotted off, so
that it was impossible to ascertain whether worms had gnawed the bases,
though this is in itself probable. Out of 121 petioles extracted from
burrows early in February, 68 were imbedded by the base, and 53 by the
apex. On February 5 all the petioles which had been drawn into the
burrows beneath a Robinia, were pulled up; and after an interval of
eleven days, 35 petioles had been again dragged in, 19 by the base, and
16 by the apex. Taking these two lots together, 56 per cent. were drawn
in by the base, and 44 per cent. by the apex. As all the softer parts
had long ago rotted off, we may feel sure, especially in the latter case,
that none had been drawn in as food. At this season, therefore, worms
drag these petioles into their burrows indifferently by either end, a
slight preference being given to the base. This latter fact may be
accounted for by the difficulty of plugging up a burrow with objects so
extremely thin as are the upper ends. In support of this view, it may be
stated that out of the 16 petioles which had been drawn in by their upper
ends, the more attenuated terminal portion of 7 had been previously
broken off by some accident.
Public-domain text, read in full here on John Shaqi.
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