UK XXXV 

 TllK OKUJIN AM) TIIK KATl Nl^TlON OK Sl'KCIMS 



Ailnpliilioii duos IKit. tU>|ii'iHl Mpun I'luiucK- 'I'lio I'liso of oviiN— or liiiil' iiiimiorv 

 All ]iorsisli-ii( oliiiuso i1o|ioiu1n nil iiiiiili>l,v on solootinii MiiUint nloi'ilil.v willioiil grout; 

 siniiHlo.'iu.'o Hol.'ilivo isoliiMou v'''7'"» i'iiriii''i7i,-t') liillui'iioo of hylii'liUziilioM I'ooii- 

 iloiuio oI'MiiooioM niir.'ri'UooN in Ihoilui-iilioiioriloi'iuloMoo -N«t.iinil(loilllioriiHliviililillH 

 I'lxl.inotilon iluo lo oNoossiv(> viii'ii\l>ililv ^I'lmoiyU' il/fi.7ii((Vrtrf(i!) iim iiiloi'pi'oloil li\ 

 liriuiilos l,o\vof ly|">H luoiv oii)mliU> of iuln|)l«Uoii lliiiii liiulior KIIhIiIIonh UIi'iIm 

 l>isiiurliMiu-o ol' lusiiliir fiuinii mikI ilom \>y oulUviillon Tlio liig'giinio ol' Coiilriil l';\ii'n|io. 



In Mu' puliir liiu'(> we linvc a case in which i\w ,n(lii|)ln(ion,s to M>o 

 lil'o condilioiiH hoth ol' (iiiio iiixl Hitnci- lire I'ccdjfiii/.ii-lilc m.h t.ho ('ir('<'li 

 iif (U'iiiiiic ciuiHt'N, luul lluis (iiH a inH't'.sMil y ; lull, llu- hiiiiui uiuh(. Ik^ I i'Uo 

 I'vorywhorc (>\('n in r(>i;'!M-(l lo (lu> nioMli coiupiox lulnplaiionM which 

 st>cni to (li'piMul ciilircly uinai cliancn ; every whci'<> MiiM|)iaiioii rcmiltM 

 ol' iicc.oHHiliy il' i(r in ])o.sHil)ic ai all witli Uio j;'i\('ii ornaiii/.aiion ol' i.h(> 

 s])ccioH — a.M ('(Miainly t\.H ih(N Miiaptaiiioii drcHH ol' llic liar<> dcpcnilH 

 on the IcMffth ol' i\w winlcr, and in point ol' Cacli not h\HH ccriaiidy 

 t.ha.n (ihc bino colonr of .slni'ch on (die arddition ol' iodine. 'The moHl, 

 deiicat^e a.da.])lia.(ionH ol' (he vei'lelii'aiiO ey(> to iiiie daHk Med I'or it liy 

 lil'o in Nin'iouH {jruupM ha^'e been i;i'adnally ln-onu'lit ailiout a.H the 

 necesMary rcHults ol' delinite i^a.nHt^H. jUHt in th<< name wa.y an tho 

 conijiJex ])i'otecti\e iiwirkiiiffH and colonrino- on tlie winj;' ol' th(» 

 Kiilli/Wifj and other leaJ'-iuiiiiickino- hiittcrllicH. 



That ada.pta,tionH can be fen-ardcd a,H niecbanicaJly nceeMsitaird 

 iw dno to tho I'art thai in every proiresH ol' ada,ptaJ.ion tlu* Hanie 

 (lii'(<cliion ol' varia.tioii on l-he paa't of tlu^ deternutia.ntH concerned w 

 gnarantetMl, Mince pei'sonal Melection cliiuiiMd.on thoM(< which vary in 

 a wrone- dire(^tion, MO thai, only tlioHo Naryinjj; in a^ Miiitabh* dir(>ction 



Miii'vivo, a,nd they th ■ontinne to \'a,i'y in the Hanie direction. !!>it 



the <j;r(^a.tcHt dill'ci'enco between oin' ('onception ol' natnra.l Hi>lcetion 

 andthato! I)a,rwin lieHiniJilH: that Darwin re^iirded it.s int(M-vcid-ion 

 UH dependent iijion chan(^{!, while we (M)nHider it aH neccMHarry a.nd 

 conditioned by the iiiiward a,n(i downwa-rd iid/ra-n-erniinal lluctiia,tioii 

 of tho (IcLi^rnnnantH. Approjiriaie variarti<iiia,l tendencicM not (ady 

 'hiiiji piMvsent thomHclvC'M, they 'iiiiid do ho, il' the ^'erni pluHin contaJiiH 

 detorn\iiiantH a-t all by whoHii lliicbiiaticjnH in a pJiiH or ndnuM direction 

 the a,ppropriate va.ria,ti(ai iH attaJnablo. 



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