VARIATION UNDER DOMESTICATION 59 



this subject, and to inspect the animals. Breeders habiV 

 ually speak of an animal's organization as something 

 plastic, which they can model almost as they please. 

 If I had space I could quote numerous 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 himself a very good judge of animals, speaks of the 

 principle of selection as "that which enables the agricul- 

 turist, 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 mold 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 recognized 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 improvement 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 



