The sole conjecture which I can form why worms line their
winter-quarters with little stones and seeds, is to prevent their
closely coiled-up bodies from coming into close contact with the
surrounding cold soil; and such contact would perhaps interfere
with their respiration which is effected by the skin alone.
A worm after swallowing earth, whether for making its burrow or for
food, soon comes to the surface to empty its body. The ejected
earth is thoroughly mingled with the intestinal secretions, and is
thus rendered viscid. After being dried it sets hard. I have
watched worms during the act of ejection, and when the earth was in
a very liquid state it was ejected in little spurts, and by a slow
peristaltic movement when not so liquid. It is not cast
indifferently on any side, but with some care, first on one and
then on another side; the tail being used almost like a trowel.
When a worm comes to the surface to eject earth, the tail
protrudes, but when it collects leaves its head must protrude.
Worms therefore must have the power of turning round in their
closely-fitting burrows; and this, as it appears to us, would be a
difficult feat. As soon as a little heap has been formed, the worm
apparently avoids, for the sake of safety, protruding its tail; and
the earthy matter is forced up through the previously deposited
soft mass.
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