VARIATION UNDER DOMESTICATION 23 



most necessary to read several of the many treatises devoted to 

 this subject, and to inspect the animals. Breeders habitually speak 

 of an animal's organization as something plastic, which they can 

 model almost as they please. If I had space I could quote numer- 

 ous passages to this effect from highly competent authorities. 

 Youatt, who was probably better acquainted with the works of 

 agriculturists than almost any other individual, and who was him- 

 self a very good judge of animals, speaks of the principle of selec- 

 tion 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." In Saxony the importance of the 

 principle of selection in regard to merino sheep is so fully recog- 

 nized 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 been exported to almost every quarter of the world. The im- 

 provement is by no means generally due to crossing different 

 breeds ; all the best breeders are strongly opposed to this practice, 

 except sometimes among closely allied sub-breeds. And when a 

 cross has been made, the closest selection is far more indispensable 

 even than in ordinary cases. If selection consisted merely in sep- 

 arating some very distinct variety, and breeding from it, the prin- 

 ciple would be so obvious as hardly to be worth notice ; but its im- 

 portance consists in the great effect produced by the accumulation 

 in one direction, during successive generations, of differences ab- 

 solutely inappreciable 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 years, and devotes his lifetime to it with indomitable 

 perseverance, he will succeed, and may make great improvements; 

 if he wants any of these qualities, he will assuredly fail. Few would 

 readily believe in the natural capacity and years of practice requi- 

 site to become even a skilful pigeon-fancier. 



The same principles are followed by horticulturists; but the 



