particles, for sharply angular bits of flint and of other hard rocks were
often found in their gizzards or intestines. On three occasions sharp
spines from the stems of rose-bushes were thus found. Worms kept in
confinement repeatedly swallowed angular fragments of hard tile, coal,
cinders, and even the sharpest fragments of glass. Gallinaceous and
struthious birds retain the same stones in their gizzards for a long
time, which thus become well rounded; but this does not appear to be the
case with worms, judging from the large number of the fragments of tiles,
glass beads, stones, &c., commonly found in their castings and
intestines. So that unless the same fragments were to pass repeatedly
through their gizzards, visible signs of attrition in the fragments could
hardly be expected, except perhaps in the case of very soft stones.
I will now give such evidence of attrition as I have been able to
collect. In the gizzards of some worms dug out of a thin bed of mould
over the chalk, there were many well-rounded small fragments of chalk,
and two fragments of the shells of a land-mollusc (as ascertained by
their microscopical structure), which latter were not only rounded but
somewhat polished. The calcareous concretions formed in the calciferous
glands, which are often found in their gizzards, intestines, and
occasionally in their castings, when of large size, sometimes appeared to
have been rounded; but with all calcareous bodies the rounded appearance
may be partly or wholly due to their corrosion by carbonic acid and the
humus-acids. In the gizzards of several worms collected in my kitchen
garden near a hothouse, eight little fragments of cinders were found, and
of these, six appeared more or less rounded, as were two bits of brick;
but some other bits were not at all rounded. A farm-road near Abinger
Hall had been covered seven years before with brick-rubbish to the depth
of about 6 inches; turf had grown over this rubbish on both sides of the
road for a width of 18 inches, and on this turf there were innumerable
castings. Some of them were coloured of a uniform red owing to the
presence of much brick-dust, and they contained many particles of brick
and of hard mortar from 1 to 3 mm. in diameter, most of which were
plainly rounded; but all these particles may have been rounded before
they were protected by the turf and were swallowed, like those on the
bare parts of the road which were much worn. A hole in a pasture-field
had been filled up with brick-rubbish at the same time, viz., seven years
ago, and was now covered with turf; and here the castings contained very
many particles of brick, all more or less rounded; and this
brick-rubbish, after being shot into the hole, could not have undergone
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