, 1879-02-22
SPARKS OF SCIENCE,

TIE Distribution or ANIMALS,
Alfred II. Wallace, the distinguished natural.
LIST, writes III the last number Of tho 4rnteieeath
Century of animals md tlleis nattvo countries.
Tic conclusion, If tie article s clear .itld con-
ciso summing up Of the whole argument, nn,l
We give It In full: "11le only mode of explain
Ing the existing distribution Of living things "
ny constant reference TO those comparatively
sliGlit but often important changes VI sen uul
lan,1, which thp most recent researches show 10
be alone probable; a'pl, what Ia still more im-
portant, by recognizing tho undoubtcd fact tllat
every group OF animals whose distribution is
disconttnuous ts nov more or Iess In frag-
oncn had much more extensive range, t.
which lts present distribution 1uaY otftr no
slew whatever. Who, woula ever llays
Imagined, for example, that ti,c llnrsc tribe, now
over the entire American Continent f,ortl, ind
Enltt!1 III great abundance niIl variety; or tlat
tt.c camel tribe, now copllned to Central Asia
and Ill: Atf'ean region ot South America, for
TACT. our existing canlels were almost ecrtainly
1csivcdl How cusy it Is to itnautue thnt anplu.
gous calises to those which have 80 recently ex-
terminated the horses Of America and Europe
t!on, md have led to the survival Ut horses
In South America aud Africa, anil their extcr-
mtl'ation elsewhere. Iiad this bcon the casc,
huS strong would have been The argument for
now know sllat tlgsc widely separated species
would 10. merely the relics of a Onco dominant
group whlct, llaa occupted md BECOME extiuct
II. all the Northern continents.
"DiscUYGr!cs OF extinct forms rpu1ntc firm,
the countri lea they now inhnbIl aru rontin,l-
nlly furnishing lis with new proofs thut tbs
great Northern continents Of the twu hctni-
sphcres vera really The birthplace Of a1ms,ss,
upon tic gtobc; wh|lu change Of climate,
eliminating in tho g'acial epocit, seems u
have been tho motive powcr which Inns driven
n,any Of these forms Into tile tropical lau.is
where they low ulone exist.
"lf VIC Eire fult weight 10 these various
considerations and at tic sa1nc time bear cotl-
stnntly tn mind the extreme Inperfectium VI
our KnowlcdEe of extinct land anIll,as, we shall,
0i the apparent anomalies fu geological dis
trbutio1, nlitl IN imagining possible alMl oyc,l
TrDbab!e solution Of those extreme cases Of
difficulty wlieh tue tac.s at our. command DO
not Ye: permit us 10 explain In detail.
Let US now briefly summarize the general
principles on which thu sulutiup Of prob,cms III
zoulorlcal distribution depends.
.'Dnr,n: The evolution Of existing forms of
animal lite, wo nny picturp to nufscycs tho
production Of successive types, each In urn ill.,
creasi,E IN variety Of species ntiA EcncrIt,
Rprrati!nE uyer i!nru or less extensive regions
uf u:1 carlll's surnee, nld them after arriving Ut
various stuces Of decay, dwis,tlliug to sirgtu
genus or FnSe SPECIES, anl ltt,ntlr bccnfs!it..
extinct. While the forms nf life uro ti.a, carii
III turn, n1nv!ng dn IRON birth 10 maturity !hu
JTUt1t maturity tn drcsr MAu dcatl, tie curll's
ruriaee Will lie undergoing Important physical
changes. wh:fi WIN sometimes unite and Botne-
times scparate contiguous continents or isanutlB,
leading nuw t. the intcrninslEg, now 10
the solntluH, OF the progressing uit,intsa!iig
groups Of at,!!ua!s. AEa!n, wc know HAT eli
mates have often cl,angel over considerable
portion Uf the earth, 50 TINT what was Mt une
tlMa, nu almost tropical region bas Lccolne ut
tIirRf ffky1re
atM u;ess changes taye, II Is believed, bern
masIy times repcatrd, leading each time IL I'M
portaft etIaugcs, lp1rrnt11l,s nnl extinctiuls VI
untlnl Ald vegetable life.
" II IL BY tic combined cIfrct OF these tfreu
distinct sets Of causes, cetinG u,ld rcactin. On
each other IN rartuus complex Wnys, thut iMru
brcil produced tt,tsc curious eyaa,pus of erratfc
distribution of species AMI gcnera wael, huvo
which ha7U ilow, Il is believed, been shown 10
hu thu natural n!kf Inevitable results Of the
PROCESS Of animal 1crciopment, combined with
constant changes III tho geography alll III tho
clisnato OF the carth." -
SENSITIVE no 1l1DICuIE.
Mr.. bldugY Hu1ton, In one Ut Ills amusing.
pHprrs on animals IN tic animal World for
February, says that dogs md 'iorses arc, ms FUR
rs he knows, the uulr animals sensitive to rtdI-
culc, wlntu cats aud birds aro wholly unaware
that they arc being laughed ut. Ilo tells Of II
pony Of his own wl,trfi geta very cross w!sn
l!sparugng rcinarks aro made upon lin. mil
II bccomts furious, aHtl stamps ab0nt hls stall.
putting hack Lfs ears, aal attempting to bItr,''
" lie IL Openly laughed Ut, whlu praise greatly
ptcases lin. Thu truth IL. TINT 1t is only tl,usu
creatures which can fec! sympathy with lian
wLlril run MISC appreciate rIdtcltlc, Tilr hursu
sstnpastzes evidently with many Of l,is r!dcr's
feelings alal unuscsncnts, willie Thu dog car en-
ter into M el,'ul! prpportop Of Ills fccligs. Isuz
birds aud THIS, though, often exceedingly airrp-
ttIo.'ate, a'M' iat Of attaeament to .ndIvtauals,
[ng9,-as Cowper's 10: Neau," Tar ,,,stauee,
rGtcre;' tnto,ths r,oet's tssre to possess him.
p!ways accompanies capocIty for sympathy.
Cstrlany toes, and proenhly horses, kuo,y .liu
ps VIC latel,, ut n fool, md beuE luuglcd :
u ia uan'tral!ou, rs WI. laugh at e
Eond collc uctor, a,itl enjoy tlc luttrr
~ tnncll as they rcsent thu former,
II Il questionable, sawcycr, wllethrr SOHO ,ur-
rots do ot undrrstAi,,l u,d enjoy tho praetice Vt
nais!ns fun OF ltleir human rquaintalirvs,-do
lot appreciate tho art Ut tltpnH, antt luke pIcas-
are tn st.-SMclator.