VARIATION UNDER DOMESTICATION 29 



very good judge of an animal, speaks of the principle of 

 selection as ' that which enables the agriculturist, not 

 only to modify the character of his flock, but to change 

 it altogether. It is the magician's wand, by means of 

 which he may summon into life whatever form and 

 mould he pleases.' Lord Somerville, speaking of 

 what breeders have done for sheep, says : — ' It would 

 seem as if they had chalked out upon a wall a form 

 perfect in itself, and then had given it existence.' 

 That most skilful breeder, Sir John Sebright, used to 

 say, with respect to pigeons, that ' he would produce 

 any given feather in three years, but it would take him 

 six years to obtain head and beak.' In Saxony the 

 importance of the principle of selection in regard to 

 merino sheep is so fully recognised, that men follow it 

 as a trade : the sheep are placed on a table and are 

 studied, like a picture by a connoisseur ; this is done 

 three times at intervals of months, and the sheep are 

 each time marked and classed, so that the very best 

 may ultimately be selected for breeding. 



What English breeders have actually effected is 

 proved by the enormous prices given for animals with a 

 good pedigree ; and these have now been exported to 

 almost every quarter of the world. The improvement is 

 by no means generally due to crossing different breeds ; 

 all the best breeders are strongly opposed to this 

 practice, except sometimes amongst closely allied sub- 

 breeds. And when a cross has been made, the closest 

 selection is far more indispensable even than in ordi- 

 nary cases. If selection consisted merely in separating 

 some very distinct variety, and breeding from it, the 

 principle would be so obvious as hardly to be worth 

 notice ; but its importance consists in the great effect 

 produced by the accumulation in one direction, during 

 successive generations, of differences absolutely in- 

 appreciable by an uneducated eye — differences which I 

 for one have vainly attempted to appreciate. Not one 

 man in a thousand has accuracy of eye and judgment 

 sufficient to become an eminent breeder. If gifted 

 with these qualities, and he studies his subject for 



