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Show 88 DARWINISM CIIAl', cracks and falls to pieces, just as occurs m a wild gourd (C. momordica).1 Variations of Flowers. Turning to flowers, we find that in tho same genus n.s om' curra-nt a,nd gooseberry, which we ha.ve cultivated for their fruits, thoro are some ornamental specie , as the Ribcs sa.nguin a, and in these the flowers have been selected so as to produce deep red pink or white varieties. \Vhcn a,nv particular flovrer hcco~ es fa;hionable and is grown in larg~ quantities, va1·i:ttions arc always met with sufficient to produce great varieties of tint or marking, as shown by our roses, auriculas, and geraniums. '\Vhen varied leaves arc required, it is found that a numb r of plants vary sufficiently in this direction al o, and we h;we zonal geraniums, variegated ivies, gold and silver marked hollies, and many others. Va1·iations of Domestic Anima/.-·. Coming now to our domesticated animals, we find st ill more extraordinary cases; and it appears as if n,Hy special qtmli ty or modification in an animal can be obtained if we only breed il in sufficient quantity, watch carefully for the required v:tria tions, and carry on selection with patience and skill for :t sufficiently long period. Thus, in sheep we have enormously increased the wool, and have obtained the power of rapidly forming flesh and fat; in cows we have incrca,scd the produ ~tion of milk; in horses we have obtained strength, enclnr:mc(', or speed, and have greatly modified size, form, and colour ; in poultry we have secured various colours of plunmge, increase of size, and almost perpetual egg-laying. But it is in dogs ;wcl pigeons that the most ma.rvellous changes ha.vc been cffccLed, and these require our special attention. Our various domestic dogs arc believed to have OJ'i gin;ttecl from several distinct wild species, because in every part of the world the native dogs resemble some wild dogs or wol ,·cs of the same country. Thus perhaps several species of wol \'Cs and jackals were domesticated in very early times, and from breeds derived from these, crossed and improved by selection, 1 These facts are taken from Darwin'::; Domesticated Animals ctncl Cultimted Plants, vol. i. pp. 359, 360, 392-401; vol. ii. pp. 231, 275, 330. JV VARIATJO UNDER DOl\1E8'1'1 'ATION our existing dogs ha,vc dcsccndccl. Bnt this intermixture of di tinct species will go a, very little W<lY in acconntirw for the peculiaritic: of the different hrecd of doo·s, nmny of '~hich arc totally unlike any wil<l animal 'nch i. the caHc with greyhounds, bloodhounds, lmlldog., Blcn hoi m spaniels, terrier:, pug , turn pits, pointers, and marry otlrer: · arr<l the ·c differ so greatly in ·izo, shape, colonr, and lmbits, as well a · in the form and proportions of all the different part. of the ho<ly that it . emus impossible that they could have descended fron~ any of the known wild doo·s, wolves, or <llliccl :wim~tls, rronc of which difl'er nearly so mnch in sim, form, nml proportions. '\V c have lrcre a rcmarkaUe proof that varia.tion is not confined to superficia,l characters- to the colour, hair, or external appendages, when we sec how the entire skeletons of snch forms as the greyhound and the lmlldog have hcen aradnally cha~1ged in opposite direction till tltcy arc l>oth c~npletely unhkc that of any known wild animal, recent or extinct. These ch;mgcs h~we been the reHult of some thom;and · of years of domestication and selection, different breeds being used and preserved for different purposes ; but some of the best breeds arc known to ha.ve been improved and perfected in modern times. Abont the middle of the la:t century a new and improved kind of foxhound wn produced; the greyhound was also greatly improved at the end of the last centmy, while the true bulldog was brought to perfection n,h ut the .-a,mc period. The Newfoundland dog has boon o mnch chanucd since it was first imported that it is now quite unlike any existing nati vo dog in that island. I Dmne ·tic Pigeons. The most rcrnarlmhle n,ml instructive cxnmplc of variation produced hy hnm:tn selection i. aflonl ccl hy the v:trions rncc's :mel breed: of dome tic pigeons, Jrot only hcc:tnsc the v;tri:ltions produced arc often mo ·t cxtraord i nary in amount and diverse in ch<tmctcr, but because in thi. case there iH no' doubt wha,tever that all ha,vc been derived from on wild species, the common rock-pio·eon (Columba livia). As this is a very important point it is well to state the evidence on which the belief is founded. The wild rock-pigeon is of a .laty-blue l See Darwin's Anirnals and Plants 1tnde1· /)omest iccttio ,~, vol. i. pp. 40·42. |
