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Show - -· -- - -· 224: SELECTION. CHAP. XXI. CHAPTER XXI. SELECTION, continued. NATURAL SELECTION AS AFFECTING DOMESTIC PRODUCTIONS- CHARACTERS WHICII APPEAR OF TRIFLING VALUE OFTEN OF REAL IMPORTANCE - CIRCUMSTANCES FAVOURABLE TO SELECTION BY MAN- FACILITY IN PREVENTING CROSSES, AND THE NATURE OF THE CONDITIO~S- CLOSE ATTENTION AND PERSEVERANCE INDISPENSABLE _ THE PRODUCTION OF A LARGE NUJIIBER OF INDIVIDUALS ESPECIALLY FAVOURABLE -WHEN NO SELECTION IS APPLIED, DISTINCT RACES Al{E NOT FORMED _ HIGHLY-Bl~ED ANIMALS LIABLE TO DEGENERATION- TEI-."'DENCY IN JIIAN TO CARRY THE SELECTION OF EACH CHARAC'fEH TO AN EXTREME POINT, LEADING TO DIVERGENCE OF CHARACTER, RARELY TO CONVERGENCE-CHARACTERS COKTINUING TO VARY IN THE SAME DIREC'riON IN WHICH THEY HAVE ALREADY VARIEDDIVERGENCE OF CHARACTER, WITH THE EX~'INCTION OF INTERMEDIATE VARIETIES, LEADS TO DISTINm'NESS IN OUR DOMESTIC RACES - LIMIT TO THE POWER OF SELECTION- LAPSE OF TilliE Il\ITORTANT- MANNER IN WHICH DOMESTIC RACES HAVE ORIGINATED- SUMMARY. Natural Selection, or the Survival of the Fittest, as affecting domestic productions.-WE know little on. this h~ad. But as animals kept by savages have to provide their own foo~, either entirely or to a large extent, throughout the year, It can hardly be doubted that, in different countries, varieties differinO' in constitution and in various characters would succeed best, 0and so be naturally selected. Hence perhaps it is that the few domesticated animals kept by savages partake, as has been remarked by more tha.n one writer, of the wild appearance of their masters, and likewise resemble natural species. Even in long-civilised countries, at least in the wilder parts, natural selection must act on our domestic races. It is obvious that varieties, having very different habits, constitution, and structure, would succeed best on mountains and on rich lowland pastures. For example, the improved Leicester sheep were formerly taken to the Lammermuir Hills ; but an intelligent sheep-master reported that " our coarse lean pastures were "unequal to the task of supporting such heavy-bodied sheep; "and they gradually dwindled away into less and less bulk: CHAP. XXT. NATURAL SELECTION. 225 " each generation was inferior to the preceding one; and when " the spring was severe, seldom more than two-thirds of the "lambs survived the ravages of the storms." 1 So with the mountain cattle of North V..T ales and the Hebrides, it has been found that they could not withstand being crossed with the larger and more delicate lowland breeds. Two French naturalists, in describing the horses of Circassia, remark that, subjected as they are to extreme vicissitudes of climate, havirig to search for scanty pasture, and exposed to constant danger from wolves, the strongest and most vigorous alone survive.2 Every one must have been struck with the surpassiug grace, strength, and vigour of the Game-cock, with its bold and confident air, its long, yet firm neck, compact body, powerful and closely pressed wings, muscular thighs, strong beak massive at the base, dense and sharp spurs set low on the legs for delivering the fatal blow, and its compact, glossy, and mail-like plumage serving as a defence. Now the English game-cock has not only been improved during many years by ma.n's careful selection, but in addition, as Mr. Tegetmeier has remarked,3 by a kind of natural selection, for the strongest, most active and courageous birds have stricken down their antagonists in the cockpit, generation after generation, and have subsequently served as the progenitors of their kind. In Great Britain, in former times, almost every district had its own breed of cattle and sheep; " they were indigenous to " the soil, climate, and pasturage of the locality on which they "grazed: they seemed to have been formed for it and by it." 4 But in this case we are quite unable to disentangle the effects of the direct action of the conditions of life,-of use or habit-of natural selection-and of that kind of selection which we have seen is occasionally and unconsciously followed by man even during the rudest periods of history. Let us now look to the action of natural selection on special characters. Although nature is difficult to resist, yet man often strives against her power, and sometimes, as we shall see, with 1 Quoted by Youatt on Sheep, p. 325. See also Youatt on CattlP, pp. 62, 69. ~ MM. Lherbette and De Quatre- VOL. II. fages, in ' Bull. Soc. Acclimat.,' tom. viii., 1861, p. 311. 3 'The Poultry Book,' ISGG, p. 123. 4 Youatt on SLeep, p. 31.2. Q |