the formation of vegetable mould-第6部分

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matter　and　were　quite　filled　with　free　calciferous　cells。　　A　great　
enlargement　in　one　direction　of　several　oval　pipes　would　give　rise　
to　the　lamellae。

Besides　the　free　calciferous　cells　in　which　no　nucleus　was　visible；　
other　and　rather　larger　free　cells　were　seen　on　three　occasions；　
and　these　contained　a　distinct　nucleus　and　nucleolus。　　They　were　
only　so　far　acted　on　by　acetic　acid　that　the　nucleus　was　thus　
rendered　more　distinct。　　A　very　small　concretion　was　removed　from　
between　two　of　the　lamellae　within　an　anterior　gland。　　It　was　
imbedded　in　pulpy　cellular　matter；　with　many　free　calciferous　
cells；　together　with　a　multitude　of　the　larger；　free；　nucleated　
cells；　and　these　latter　cells　were　not　acted　on　by　acetic　acid；　
while　the　former　were　dissolved。　　From　this　and　other　such　cases　I　
am　led　to　suspect　that　the　calciferous　cells　are　developed　from　the　
larger　nucleated　ones；　but　how　this　was　effected　was　not　
ascertained。

When　an　anterior　gland　contains　several　minute　concretions；　some　of　
these　are　generally　angular　or　crystalline　in　outline；　while　the　
greater　number　are　rounded　with　an　irregular　mulberry…like　surface。　　
Calciferous　cells　adhered　to　many　parts　of　these　mulberry…like　
masses；　and　their　gradual　disappearance　could　be　traced　while　they　
still　remained　attached。　　It　was　thus　evident　that　the　concretions　
are　formed　from　the　lime　contained　within　the　free　calciferous　
cells。　　As　the　smaller　concretions　increase　in　size；　they　come　into　
contact　and　unite；　thus　enclosing　the　now　functionless　lamellae；　
and　by　such　steps　the　formation　of　the　largest　concretions　could　be　
followed。　　Why　the　process　regularly　takes　place　in　the　two　
anterior　glands；　and　only　rarely　in　the　four　posterior　glands；　is　
quite　unknown。　　Morren　says　that　these　glands　disappear　during　the　
winter；　and　I　have　seen　some　instances　of　this　fact；　and　others　in　
which　either　the　anterior　or　posterior　glands　were　at　this　season　
so　shrunk　and　empty；　that　they　could　be　distinguished　only　with　
much　difficulty。

With　respect　to　the　function　of　the　calciferous　glands；　it　is　
probable　that　they　primarily　serve　as　organs　of　excretion；　and　
secondarily　as　an　aid　to　digestion。　　Worms　consume　many　fallen　
leaves；　and　it　is　known　that　lime　goes　on　accumulating　in　leaves　
until　they　drop　off　the　parent…plant；　instead　of　being　re…absorbed　
into　the　stem　or　roots；　like　various　other　organic　and　inorganic　
substances。　｛25｝　　The　ashes　of　a　leaf　of　an　acacia　have　been　known　
to　contain　as　much　as　72　per　cent。　of　lime。　　Worms　therefore　would　
be　liable　to　become　charged　with　this　earth；　unless　there　were　some　
special　means　for　its　excretion；　and　the　calciferous　glands　are　
well　adapted　for　this　purpose。　　The　worms　which　live　in　mould　close　
over　the　chalk；　often　have　their　intestines　filled　with　this　
substance；　and　their　castings　are　almost　white。　　Here　it　is　evident　
that　the　supply　of　calcareous　matter　must　be　super…abundant。　　
Nevertheless　with　several　worms　collected　on　such　a　site；　the　
calciferous　glands　contained　as　many　free　calciferous　cells；　and　
fully　as　many　and　large　concretions；　as　did　the　glands　of　worms　
which　lived　where　there　was　little　or　no　lime；　and　this　indicates　
that　the　lime　is　an　excretion；　and　not　a　secretion　poured　into　the　
alimentary　canal　for　some　special　purpose。

On　the　other　hand；　the　following　considerations　render　it　highly　
probable　that　the　carbonate　of　lime；　which　is　excreted　by　the　
glands；　aids　the　digestive　process　under　ordinary　circumstances。　　
Leaves　during　their　decay　generate　an　abundance　of　various　kinds　of　
acids；　which　have　been　grouped　together　under　the　term　of　humus　
acids。　　We　shall　have　to　recur　to　this　subject　in　our　fifth　
chapter；　and　I　need　here　only　say　that　these　acids　act　strongly　on　
carbonate　of　lime。　　The　half…decayed　leaves　which　are　swallowed　in　
such　large　quantities　by　worms　would；　therefore；　after　they　have　
been　moistened　and　triturated　in　the　alimentary　canal；　be　apt　to　
produce　such　acids。　　And　in　the　case　of　several　worms；　the　contents　
of　the　alimentary　canal　were　found　to　be　plainly　acid；　as　shown　by　
litmus　paper。　　This　acidity　cannot　be　attributed　to　the　nature　of　
the　digestive　fluid；　for　pancreatic　fluid　is　alkaline；　and　we　have　
seen　that　the　secretion　which　is　poured　out　of　the　mouths　of　worms　
for　the　sake　of　preparing　the　leaves　for　consumption；　is　likewise　
alkaline。　　The　acidity　can　hardly　be　due　to　uric　acid；　as　the　
contents　of　the　upper　part　of　the　intestine　were　often　acid。　　In　
one　case　the　contents　of　the　gizzard　were　slightly　acid；　those　of　
the　upper　intestines　being　more　plainly　acid。　　In　another　case　the　
contents　of　the　pharynx　were　not　acid；　those　of　the　gizzard　
doubtfully　so；　while　those　of　the　intestine　were　distinctly　acid　at　
a　distance　of　5　cm。　below　the　gizzard。　　Even　with　the　higher　
herbivorous　and　omnivorous　animals；　the　contents　of　the　large　
intestine　are　acid。　　〃This；　however；　is　not　caused　by　any　acid　
secretion　from　the　mucous　membrane；　the　reaction　of　the　intestinal　
walls　in　the　larger　as　in　the　small　intestine　is　alkaline。　　It　must　
therefore　arise　from　acid　fermentations　going　on　in　the　contents　
themselves　。　。　。　　In　Carnivora　the　contents　of　the　coecum　are　said　
to　be　alkaline；　and　naturally　the　amount　of　fermentation　will　
depend　largely　on　the　nature　of　the　food。〃　｛26｝

With　worms　not　only　the　contents　of　the　intestines；　but　their　
ejected　matter　or　the　castings；　are　generally　acid。　　Thirty　
castings　from　different　places　were　tested；　and　with　three　or　four　
exceptions　were　found　to　be　acid；　and　the　exceptions　may　have　been　
due　to　such　castings　not　having　been　recently　ejected；　for　some　
which　were　at　first　acid；　were　on　the　following　morning；　after　
being　dried　and　again　moistened；　no　longer　acid；　and　this　probably　
resulted　from　the　humus　acids　being；　as　is　known　to　be　the　case；　
easily　decomposed。　　Five　fresh　castings　from　worms　which　lived　in　
mould　close　over　the　chalk；　were　of　a　whitish　colour　and　abounded　
with　calcareous　matter；　and　these　were　not　in　the　least　acid。　　This　
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