THE DARWINIAN THEORY 39 



head a little longer than usual, and mated for breeding. Among its 

 descendants there will probably be some which also exhibit these 

 slightly prominent feathers, and possibly there may be one or other 

 of them which has these feathers considerably lengthened. This one 

 is then used for breeding, and by continually proceeding thus, and 

 selecting for breeding, from generation to generation, only the 

 individuals which approach most nearly to the desired end, the 

 wished-for character is at last secured. 



Thus it is not by crossing of different breeds, but by a patient 

 accumulating of insignificant little variations through many genera- 

 tions, that the desired transformations are brought about. That is 

 the magic wand by means of which the expert breeder produces his 

 different breeds, we might almost say, as the sculptor moulds and 

 remoulds his clay model according to his fancy. Quite according to 

 his fancy the breeder has brought about all the fantastic forms we 

 are familiar with among pigeons, mere variations which are of no 

 use either to the bird itself or to man, which simply gratify man's 

 whim without in many cases even satisfying his sense of beauty. 

 For many of the existing breeds of pigeons, hens, and other domesti- 

 cated animals, are anything but beautiful, the body being often 

 unharmonious in structure and sometimes actually monstrous. 



Among pigeons, as well as among other domesticated animals, 

 some changes have been brought about, which are not only of no use 

 to their possessors, but would be actually disadvantageous if they 

 were living under natural conditions. Some of the very short-billed 

 breeds of pigeons have the bill so short and soft that the young can 

 no longer use it to scratch and break the egg-shell, and would perish 

 miserably if human aid were not at hand. The Yorkshire pig has 

 become such a colossus of fat on weak, short legs, that if it were 

 dependent on its own resources, it could not secure its food, much less' 

 escape from a beast of prey ; and among horses the heavy cart-horse 

 and the racer are alike unfit to cope with the dangers of a wild life, 

 or the vicissitudes of weather. 



Breeding has done much to bring about variations useful to man. 

 Thus we have breeds of cattle which excel in flesh, or in milk, or as 

 draught animals, and sheep which excel in flesh or in wool, and to 

 what a height the perfecting of a useful quality can be brought is 

 shown, in regard to fineness of wool, by that finest breed of sheep, 

 the merino, which instead of the 5,500 hairs borne by the old German 

 sheep on a square inch, possesses 48,000. 



Not infrequently it is a particular stage of a species that has 

 been bred by man, and the other stages have remained more or less 



