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shows how effectually carbonate of lime neutralises the intestinal
acids。 When worms were kept in pots filled with fine ferruginous
sand； it was manifest that the oxide of iron； with which the grains
of silex were coated； had been dissolved and removed from them in
the castings。
The digestive fluid of worms resembles in its action； as already
stated； the pancreatic secretion of the higher animals； and in
these latter； 〃pancreatic digestion is essentially alkaline； the
action will not take place unless some alkali be present； and the
activity of an alkaline juice is arrested by acidification； and
hindered by neutralization。〃 ｛27｝ Therefore it seems highly
probable that the innumerable calciferous cells； which are poured
from the four posterior glands into the alimentary canal of worms；
serve to neutralise more or less completely the acids there
generated by the half…decayed leaves。 We have seen that these
cells are instantly dissolved by a small quantity of acetic acid；
and as they do not always suffice to neutralise the contents of
even the upper part of the alimentary canal； the lime is perhaps
aggregated into concretions in the anterior pair of glands； in
order that some may be carried down to the posterior parts of the
intestine； where these concretions would be rolled about amongst
the acid contents。 The concretions found in the intestines and in
the castings often have a worn appearance； but whether this is due
to some amount of attrition or of chemical corrosion could not be
told。 Claparede believes that they are formed for the sake of
acting as mill…stones； and of thus aiding in the trituration of the
food。 They may give some aid in this way； but I fully agree with
Perrier that this must be of quite subordinate importance； seeing
that the object is already attained by stones being generally
present in the gizzards and intestines of worms。
CHAPTER IIHABITS OF WORMScontinued。
Manner in which worms seize objectsTheir power of suctionThe
instinct of plugging up the mouths of their burrowsStones piled
over the burrowsThe advantages thus gainedIntelligence shown by
worms in their manner of plugging up their burrowsVarious kinds
of leaves and other objects thus usedTriangles of paperSummary
of reasons for believing that worms exhibit some intelligence
Means by which they excavate their burrows； by pushing away the
earth and swallowing itEarth also swallowed for the nutritious
matter which it containsDepth to which worms burrow； and the
construction of their burrowsBurrows lined with castings； and in
the upper part with leavesThe lowest part paved with little
stones or seedsManner in which the castings are ejectedThe
collapse of old burrowsDistribution of wormsTower…like castings
in BengalGigantic castings on the Nilgiri MountainsCastings
ejected in all countries。
In the pots in which worms were kept； leaves were pinned down to
the soil； and at night the manner in which they were seized could
be observed。 The worms always endeavoured to drag the leaves
towards their burrows； and they tore or sucked off small fragments；
whenever the leaves were sufficiently tender。 They generally
seized the thin edge of a leaf with their mouths； between the
projecting upper and lower lip； the thick and strong pharynx being
at the same time； as Perrier remarks； pushed forward within their
bodies； so as to afford a point of resistance for the upper lip。
In the case of broad flat objects they acted in a wholly different
manner。 The pointed anterior extremity of the body； after being
brought into contact with an object of this kind； was drawn within
the adjoining rings； so that it appeared truncated and became as
thick as the rest of the body。 This part could then be seen to
swell a little； and this； I believe； is due to the pharynx being
pushed a little forwards。 Then by a slight withdrawal of the
pharynx or by its expansion； a vacuum was produced beneath the
truncated slimy end of the body whilst in contact with the object；
and by this means the two adhered firmly together。 ｛28｝ That under
these circumstances a vacuum was produced was plainly seen on one
occasion； when a large worm lying beneath a flaccid cabbage leaf
tried to drag it away； for the surface of the leaf directly over
the end of the worm's body became deeply pitted。 On another
occasion a worm suddenly lost its hold on a flat leaf； and the
anterior end of the body was momentarily seen to be cup…formed。
Worms can attach themselves to an object beneath water in the same
manner； and I saw one thus dragging away a submerged slice of an
onion…bulb。
The edges of fresh or nearly fresh leaves affixed to the ground
were often nibbled by the worms； and sometimes the epidermis and
all the parenchyma on one side was gnawed completely away over a
considerable space； the epidermis alone on the opposite side being
left quite clean。 The veins were never touched； and leaves were
thus sometimes partly converted into skeletons。 As worms have no
teeth and as their mouths consist of very soft tissue； it may be
presumed that they consume by means of suction the edges and the
parenchyma of fresh leaves； after they have been softened by the
digestive fluid。 They cannot attack such strong leaves as those of
sea…kale or large and thick leaves of ivy； though one of the latter
after it had become rotten was reduced in parts to the state of a
skeleton。
Worms seize leaves and other objects； not only to serve as food；
but for plugging up the mouths of their burrows； and this is one of
their strongest instincts。 They sometimes work so energetically
that Mr。 D。 F。 Simpson； who has a small walled garden where worms
abound in Bayswater； informs me that on a calm damp evening he
there heard so extraordinary a rustling noise from under a tree
from which many leaves had fallen； that he went out with a light
and discovered that the noise was caused by many worms dragging the
dry leaves and squeezing them into the burrows。 Not only leaves；
but petioles of many kinds； some flower…peduncles； often decayed
twigs of trees； bits of paper； feathers； tufts of wool and horse…
hairs are dragged into their burrows for this purpose。 I have seen
as many as seventeen petioles of a Clematis projecting from the
mouth of one burrow； and ten from the mouth of another。 Some of
these objects； such as the petioles just named； feathers； &c。； are
never gnawed by worms。 In a gravel…walk in my garden I found many
hundred leaves of a pine…tree （P。 austriaca or nigricans） drawn by
their bases into burrows。 The surfaces by which these leaves are
articulated to the branches are shaped in as peculiar a manner as
is the joint between the leg…bones of a quadruped； and if these
surfaces had been in the least gnawed； the fact would have been
immediately visible； but there was no trace of gnawing。 Of
ordinary dicotyledonous leaves； all those which are dragged into
burrows are not gnawed。 I have seen as many as nine leaves of the
lime…tree drawn into the same burrow； and not nearly all of them
had been