the intersected chambers. I found at Abinger in Surrey two burrows
terminating in similar chambers at a depth of 36 and 41 inches, and these
were lined or paved with little pebbles, about as large as mustard seeds;
and in one of the chambers there was a decayed oat-grain, with its husk.
Hensen likewise states that the bottoms of the burrows are lined with
little stones; and where these could not be procured, seeds, apparently
of the pear, had been used, as many as fifteen having been carried down
into a single burrow, one of which had germinated. {108} We thus see how
easily a botanist might be deceived who wished to learn how long deeply
buried seeds remained alive, if he were to collect earth from a
considerable depth, on the supposition that it could contain only seeds
which had long lain buried. It is probable that the little stones, as
well as the seeds, are carried down from the surface by being swallowed;
for a surprising number of glass beads, bits of tile and of glass were
certainly thus carried down by worms kept in pots; but some may have been
carried down within their mouths. 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. The mouth of the same
burrow is used for this purpose for a considerable time. In the case of
the tower-like castings (see Fig. 2) near Nice, and of the similar but
still taller towers from Bengal (hereafter to be described and figured),
a considerable degree of skill is exhibited in their construction. Dr.
53