70 THE ORIGIN OF SPECIES 



Yorkshire, '*as they general y belong to poor people, f nd 

 are mostly in small lots, they never can be improved." 

 Ou the other hand, nurserymen, from keeping large 

 stocks of the same plant, are generally far more success- 

 ful than amateurs in raising new and valuable varieties. 

 A large number of individuals of an animal or plant can 

 be reared only where the conditions for its propagation 

 are favorable. "When the individuals are scanty, all will 

 be allowed to breed, whatever their quality may be, and 

 this will effectually prevent selection. But probably the 

 most important element is that the animal or plant should 

 be so highly valued by man that the closest attention is 

 paid to even the slightest deviations in its qualities 

 or structure. Unless such attention be paid nothing can 

 be effected. I have seen it gravely remarked that it was 

 most fortunate that the strawberry began to vary just 

 when gardeners began to attend to this plant. No doubt 

 the strawberry had always varied since it was cultivated, 

 but the slight varieties had been neglected. As soon, 

 however, as gardeners picked out individual plants with 

 slightly larger, earlier, or better fruit, and raised seedlmgs 

 from them, and again picked out the best seedlings and 

 bred from them, then (with some aid by crossing distinct 

 species) those many admirable varieties of the strawberry 

 were raised which have appeared during the last half- 

 century. 



With animals, facility in preventing crosses is an im- 

 portant element in the formation of new races — at least, 

 in a country which is already stocked with other races. 

 In this respect inclosure of the land plays a part. Wan- 

 dering savages or the inhabitants of open plains rarely 

 possess more than one breed of the same speciea Pig- 



