Page:Encyclopædia Britannica, Ninth Edition, v. 4.djvu/295

Rh practised from exceedingly ancient times. The results pro duced by prolonged selection of this kind may be estimated in various ways. For instance, although it is certain that the pointer originally came from Spain, no such breed exists there at the present day. So far as is known no efforts have ever been made to modify the pointer ; but every one has wished to possess as good dogs as possible, and by au unconscious consensus of opinion, the desire for improve ment has resulted in a slow progressive change in a certain direction. But the amount of divergence produced by long- continued selection may be illustrated more forcibly by general considerations than by special instances. The fact that the progenitors of many cultivated plants and domestic animals cannot with certainty be determined points out the great divergence from the wild parent form that has been effected under domestication. The genus Auchenia may serve as an illustration. There are four forms in this genus the guanaco and vicuna, found wild, and undoubtedly dis tinct species, and the llama and alpaca, known only in a domesticated condition. Most professed naturalists have looked on all four forms as specifically distinct, and have made the assumption that the wild llama and alpaca have become extinct. But Mr Ledger appears to have proved conclusively 1 that the llama is the domesticated descendant of the guanaco, and the alpaca that of the vicuna, so that a large amount of divergence must have been effected in this case. - And as we know that careful selection was anciently applied to these animals, there is nothing inconceivable in such a transformation having been effected. The power of long-continued selection is well shown by the fact that, in domestic animals and plants, the parts or qualities valued by man have been most modified ; thus the sheep has been prized during many ages for its fleece, the horse for its strength and fleetness, and, accordingly, we do not find breeds of sheep differing from each other in strength and fleetness, or breeds of horses distinguished by the properties of their hair, but on the contrary both animals have pro duced races characterized by differences in the qualities for which they are valued. The same law is even more clearly demonstrated by plants under cultivation. In the radish, which has been esteemed exclusively for its root, it is the latter that differs in the several varieties, while the flowers, peed, and foliage are almost identical in all. Again, the varieties of the gooseberry differ much in their fruit, but hardly perceptibly in their flowers and organs of reproduc tion. In some cases structures neglected by man have varied by correlation ; but allowing for this exception, they may be said to have escaped the effects of selection, and accordingly to have remained stationary, while the selected qualities have gradually improved. In attempting to frame an answer to the question TIow much has man actually effected it will be well first to estimate the amount of modification which may be claimed as his work, and then to measure the efficiency of the agents by which these results are believed to have been effected. (1.) Organic beings resemble each other in descending degrees, so that they can be classed in groups under groups, classes, orders, genera, &c. The doctrine of evolution gives life to this arrangement and makes it truly a &quot; natural&quot; classification, the idea of different degrees of community of descent being added to that of arbitrary classification by community of characteristics. Thus it happens that the number and distinctness of the genera contained in a natural family become to a certain extent a gauge of the amount of divergence which the modifying causes of nature have produced, since the time when all the genera were united in the parent form of their family. And by a similar method we may estimate the amount of divergence that man has effected. For instance, there can be no doubt that all the varieties of the domestic pigeon are the descendants of the rock pigeon, and have sprung up under the care of man during the long period of time that has elapsed since their wild ancestor was first domesticated. These varieties amount to more than 150 in number ; and there can be no question that, supposing them to be found wild, they would be grouped under at least five distinct genera, so great are differences existing among them. This instance gives some idea of the marvellous amount of modification that may arise under domestication. (2.) Are the powers which man possesses of producing modification sufficient for the work assigned to them 1 It will be well to set down the assumptions which may fairly be made in connection with this point. First, the labours of the great breeders teach us what enormous changes can be effected in the short space of one man s life ; and we know that the essential principles in volved in the process were anciently known and followed. Secondly, we may feel certain that great divergence of character is unconsciously produced during long continued selection of any kind; and we know that some kind of selection must have existed from remote periods. Logically considered, therefore, the possibility of almost any degree of divergence having been effected turns in great measure on the question of the antiquity of selection. It is therefore important to note that an indirect kind of selection must almost necessarily be coeval with domestica tion. For this can be shown to be the case with tame ani mals possessed by the rudest savage, who does not regulate their increase in accordance with even the vaguest belief in heredity. In each litter of puppies, for instance, some would necessarily be destroyed, for their master would be unable to preserve all the young ones which were produced. He would certainly not save those which were small, feeble, or deficient in any valuable quality. The finest in each generation would then be preserved, merely because it was believed that they, individually, would be useful, and not with any idea of &quot;breeding.&quot; Nevertheless, it would in directly follow that the superior individuals in each genera tion would, as a rule, form the progenitors of the next one ; that is, a kind of indirect selection would arise. If then we can be sure that domestication, in some form, has existed from remote times, we may feel tolerably certain that the above-described rude form of selection must be of nearly equal antiquity. Apart from the direct proofs 011 this head which we possess in the remains of the prehistoric period, there is a high antecedent probability in favour of the ex treme antiquity of domestication ; for it is certain that tame animals are of great use to savages, and the wild progenitors of many of our domestic creatures are rendered tame with ease. This is the case with wild dogs, pigs, cattle, ducks, &c. In the case of vegetables, it appears that, in times of scarcity, savages devour almost any berries or leaves which they can obtain, often suffering terribly in consequence ; and in this way plants at all superior in nutritious qualities would assuredly be discovered. We may, therefore, con clude (1), that the domestication of animals and the cul ture of plants date from exceedingly remote antiquity; (2), that a certain amount of selection must have been nearly coeval with domestication ; (3), that some degree of divergence of character must almost necessarily have accom panied selection; and (4), that, consequently, the large amount of modification claimed to have been produced by man is a conceivable and credible result.  BREGENTZ, the ancient Briyantia, capital of the circle of Vorarlberg, in Tyrol, stands on a hill at the S.E. end of the Lake of Constance. It has an old castle, two con vents, and an orphanage. Silk and cotton are manufac- 