the perpetuation of living beings-第3节

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case　had　come　under　his　notice　of　a　variation　in　the　form　of　a　human
member；　in　the　person　of　a　Maltese；　of　the　name　of　Gratio　Kelleia；　who
was　born　with　six　fingers　upon　each　hand；　and　the　like　number　of　toes
to　each　of　his　feet。　　That　was　a　case　of　spontaneous　variation。　　Nobody
knows　why　he　was　born　with　that　number　of　fingers　and　toes；　and　as　we
don't　know；　we　call　it　a　case　of　〃spontaneous〃　variation。　　There　is
another　remarkable　case　also。　　I　select　these；　because　they　happen　to
have　been　observed　and　noted　very　carefully　at　the　time。　　It　frequently
happens　that　a　variation　occurs；　but　the　persons　who　notice　it　do　not
take　any　care　in　noting　down　the　particulars；　until　at　length；　when
inquiries　come　to　be　made；　the　exact　circumstances　are　forgotten；　and
hence；　multitudinous　as　may　be　such　〃spontaneous〃　variations；　it　is
exceedingly　difficult　to　get　at　the　origin　of　them。

The　second　case　is　one　of　which　you　may　find　the　whole　details　in　the
〃Philosophical　Transactions〃　for　the　year　1813；　in　a　paper　communicated
by　Colonel　Humphrey　to　the　President　of　the　Royal　Society；〃On　a　new
Variety　in　the　Breed　of　Sheep；〃　giving　an　account　of　a　very　remarkable
breed　of　sheep；　which　at　one　time　was　well　known　in　the　northern　states
of　America；　and　which　went　by　the　name　of　the　Ancon　or　the　Otter　breed
of　sheep。　　In　the　year　1791；　there　was　a　farmer　of　the　name　of　Seth
Wright　in　Massachusetts；　who　had　a　flock　of　sheep；　consisting　of　a　ram
and；　I　think；　of　some　twelve　or　thirteen　ewes。　　Of　this　flock　of　ewes；
one　at　the　breeding…time　bore　a　lamb　which　was　very　singularly　formed；
it　had　a　very　long　body；　very　short　legs；　and　those　legs　were　bowed！　　I
will　tell　you　by…and…by　how　this　singular　variation　in　the　breed　of
sheep　came　to　be　noted；　and　to　have　the　prominence　that　it　now　has。　For
the　present；　I　mention　only　these　two　cases；　but　the　extent　of　variation
in　the　breed　of　animals　is　perfectly　obvious　to　any　one　who　has　studied
natural　history　with　ordinary　attention；　or　to　any　person　who　compares
animals　with　others　of　the　same　kind。　　It　is　strictly　true　that　there
are　never　any　two　specimens　which　are　exactly　alike；　however　similar；
they　will　always　differ　in　some　certain　particular。

Now　let　us　go　back　to　Atavism；to　the　hereditary　tendency　I　spoke　of。
What　will　come　of　a　variation　when　you　breed　from　it；　when　Atavism
comes；　if　I　may　say　so；　to　intersect　variation？　The　two　cases　of　which
I　have　mentioned　the　history；　give　a　most　excellent　illustration　of
what　occurs。　　Gratio　Kelleia；　the　Maltese；　married　when　he　was
twenty…two　years　of　age；　and；　as　I　suppose　there　were　no　six…fingered
ladies　in　Malta；　he　married　an　ordinary　five…fingered　person。　　The
result　of　that　marriage　was　four　children；　the　first；　who　was　christened
Salvator；　had　six　fingers　and　six　toes；　like　his　father；　the　second　was
George；　who　had　five　fingers　and　toes；　but　one　of　them　was　deformed；
showing　a　tendency　to　variation；　the　third　was　Andre；　he　had　five
fingers　and　five　toes；　quite　perfect；　the　fourth　was　a　girl；　Marie；　she
had　five　fingers　and　five　toes；　but　her　thumbs　were　deformed；　showing　a
tendency　toward　the　sixth。

These　children　grew　up；　and　when　they　came　to　adult　years；　they　all
married；　and　of　course　it　happened　that　they　all　married　five…fingered
and　five…toed　persons。　　Now　let　us　see　what　were　the　results。　　Salvator
had　four　children；　they　were　two　boys；　a　girl；　and　another　boy；　the
first　two　boys　and　the　girl　were　six…fingered　and　six…toed　like　their
grandfather；　the　fourth　boy　had　only　five　fingers　and　five　toes。　George
had　only　four　children；　there　were　two　girls　with　six　fingers　and　six
toes；　there　was　one　girl　with　six　fingers　and　five　toes　on　the　right
side；　and　five　fingers　and　five　toes　on　the　left　side；　so　that　she　was
half　and　half。　　The　last；　a　boy；　had　five　fingers　and　five　toes。　　The
third；　Andre；　you　will　recollect；　was　perfectly　well…formed；　and　he　had
many　children　whose　hands　and　feet　were　all　regularly　developed。　　Marie；
the　last；　who；　of　course；　married　a　man　who　had　only　five　fingers；　had
four　children；　the　first；　a　boy；　was　born　with　six　toes；　but　the　other
three　were　normal。

Now　observe　what　very　extraordinary　phenomena　are　presented　here。　　You
have　an　accidental　variation　arising　from　what　you　may　call　a
monstrosity；　you　have　that　monstrosity　tendency　or　variation　diluted　in
the　first　instance　by　an　admixture　with　a　female　of　normal　construction；
and　you　would　naturally　expect　that；　in　the　results　of　such　an　union；
the　monstrosity；　if　repeated；　would　be　in　equal　proportion　with　the
normal　type；　that　is　to　say；　that　the　children　would　be　half　and　half；
some　taking　the　peculiarity　of　the　father；　and　the　others　being　of　the
purely　normal　type　of　the　mother；　but　you　see　we　have　a　great
preponderance　of　the　abnormal　type。　Well；　this　comes　to　be　mixed　once
more　with　the　pure；　the　normal　type；　and　the　abnormal　is　again　produced
in　large　proportion；　notwithstanding　the　second　dilution。　　Now　what
would　have　happened　if　these　abnormal　types　had　intermarried　with　each
other；　that　is　to　say；　suppose　the　two　boys　of　Salvator　had　taken　it
into　their　heads　to　marry　their　first　cousins；　the　two　first　girls　of
George；　their　uncle？　　You　will　remember　that　these　are　all　of　the
abnormal　type　of　their　grandfather。　　The　result　would　probably　have
been；　that　their　offspring　would　have　been　in　every　case　a　further
development　of　that　abnormal　type。　　You　see　it　is　only　in　the　fourth；
in　the　person　of　Marie；　that　the　tendency；　when　it　appears　but　slightly
in　the　second　generation；　is　washed　out　in　the　third；　while　the　progeny
of　Andre；　who　escaped　in　the　first　instance；　escape　altogether。

We　have　in　this　case　a　good　example　of　nature's　tendency　to　the
perpetuation　of　a　variation。　Here　it　is　certainly　a　variation　which
carried　with　it　no　use　or　benefit；　and　yet　you　see　the　tendency　to
perpetuation　may　be　so　strong；　that；　notwithstanding　a　great　admixture
of　pure　blood；　the　variety　continues　itself　up　to　the　third　generation；
which　is　largely　marked　with　it。　In　this　case；　as　I　have　said；　there
was　no　means　of　the　second　generation　intermarrying　with　any　but
five…fingered　persons；　and　the　question　naturally　suggests　itself；　What
would　have　been　the　result　of　such　marriage？　　Reaumur　narrates　this
case　only　as　far　as　the　third　generation。　　Certainly　it　would　have　been
an　exceedingly　curious　thing　if　we　could　have　traced　this　matter　any
further；　had　the　cousins　intermarried；　a　six…fingered　variety　of　the
human　race　might　have　been　set　up。

To　show　you　that　this　supposition　is　by　no　means　an　unreasonable　one；
let　me　now　point　out　what　took　place　in　the　case　of　Seth　Wright's
sheep；　where　it　happened　to　be　a　matter　of　moment　to　him　to　obtain　a
breed　or　raise　a　flock　of　sheep　like　that　accidental　variety　that　I
have　describedand　I　will　tell　you　why。　　In　that　part　of　Massachusetts
where　Seth　Wright　was　living；　the　fields　were　separated　by　fences；　and
the　sheep；　which　were　very　active　and　robust；　would　roam　abroad；　and
without　much　difficulty　jump　over　these　fences　into　other　people's
farms。　　As　a　matter　of　course；　this　exuberant　activity　on　the　part　of
the　sheep　constantly　gave　rise　to　all　sorts　of　quarrels；　bickerings；
and　contentions　among　the　farmers　of　the　neighbourhood；　so　it　occurred
to　Seth　Wright；　who　was；　like　his　successors；　more　or　less　'cute；　that
if　he　could　get　a　stock　of　sheep　like　those　with　the　bandy　legs；　they
would　not　be　able　to　jump　over　the　fences　so　readily；　and　he　acted　upon
that　idea。　　He　killed　his　old　ram；　and　as　soon　as　the　young　one　arrived
at　maturity；　he　bred　altogether　from　it。　　The　result　was　even　more
striking　than　in　the　human　experiment　which　I　mentioned　just　now。
Colonel　Humphreys　testifies　that　it　always　happened　that　the　offspring
were　either　pure　Ancons　or　pure　ordinary　sheep；　that　in　no　case　was
there　any　mixing　of　the　Ancons　with　the　others。　　In　consequence　of
this；　in　the　course　of　a　very　few　years；　the　farmer　was　able　to　get　a
very　considerable　flock　of　this　variety；　and　a　large　number　of　them
were　spread　throughout　Massachusetts。　　Most　unfortunately；　howeverI
suppose　it　was　because　they　were　so　commonnobody　took　enough　notice
of　them　to　preserve　their　skeletons；　and　although　Colonel　Humphreys
states　that　he　sent　a　skeleton　to　the　President　of　the　Royal　Society　at
the　same　time　that　he　forwarded　his　paper；　I　am　afraid　that　the　variety
has　entirely　disappeared；　for　a　short　time　after　these　sheep　had　become
prevalent　in　that　district；　the　Merino　sheep　were　introduced；　and　as
their　wool　was　much　more　valuable；　and　as　they　were　a　quiet　race　of
sheep；　and　showed　no　tendency　to　trespass　or　jump　over　fences；　the
Otter　breed　of　sheep；　the　wool　of　which　was　inferior　to　that　of　the
Merino；　was　gradually　allowed　to　die　out。

You　see　that　these　facts　illustrate　perfectly　well　what　may　be　done　if
you　take　care　to　breed　from　stocks　that　are　similar　to　each　other。
After　having　got　a　variation；　if；　by　crossing　a　variation　with　the
original　stock；　you　multiply　that　variation；　and　then　take　care　to　keep
that　variation　distinct　from　the　original　stock；　and　make　them　breed
together；then　you　may　almost　certainly