Chap. I. 
SELECTION BY MAN. 
31 
a large extent some breeds of cattle and sheep. In 
order fully to realise what they have done, it is almost 
necessary to read several of the many treatises devoted 
to this subject/and to inspect the animals. Breeders 
habitually speak of an animal’s organisation as some¬ 
thing quite 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 worlcs of 
agriculturists than almost any other individual, and who 
was himself a 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 what¬ 
ever 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 im¬ 
portance 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; 
