26 SELECTION BY MAN. 



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 some- 

 times among closely allied sub-breeds. And when a cross 

 lias been made, the closest selection is far more indispens- 

 able even than in ordinary cases. If selection consisted 

 merely in separating some very distinct variety, and breed- 

 ing 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 inapprecia- 

 ble 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 quali- 

 ties, 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 requisite 

 to become even a skilful pigeon-fancier. 



The same principles are followed by horticulturists ; but 

 the variations are here often more abrupt. No one sup- 

 poses that our choicest productions have been produced 

 by a single variation from the aboriginal stock. We have 

 proofs that this has not been so in several cases in which 

 exact records have been kept ; thus, to give a very trifling 

 instance, the steadily increasing size of the common goose- 

 berry may be quoted. We see an astonishing improvement 

 in many florists' flowers, when the flowers of the present 

 day are compared with drawings made only twenty or 

 thirty years ago. When a race of plants is once pretty well 

 established, the seed-raisers do not pick out the best plants, 

 but merely go over their seed-beds, and pull up the 

 " rogues," as they call the plants that deviate from the 

 proper standard. With animals this kind of selection is, 

 in fact, likewise followed ; for hardly any one is so careless 

 as to breed from his worst animals. 



In regard to plants, there is another means of observing 

 the accumulated effects of selection — namely, by comparing 

 the diversity of flowers in the different varieties of the same 

 species in the flower garden j the diversity of leaves, pods, 



