the formation of vegetable mould-第7节

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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　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　th