54 ORIGIN OF SPECIES 



trict than in another, according to the state of civilisation of 

 the inhabitants, — slowly to add to the characteristic features 

 of the breed, whatever they may be. But the chance will be 

 infinitely small of any record having been preserved of such 

 slow, varying, and insensible changes. 



CIRCUMSTANCES FAVOURABLE TO MAN's POWER OF SELECTION 



I will now say a few words on the circumstances, favour- 

 able, or the reverse, to man's power of selection. A high de- 

 gree of variability is obviously favourable, as freely giving 

 the materials for selection to work on; not that mere indi- 

 vidual differences are not amply sufficient, with extreme care, 

 to allow of the accumulation of a large amount of modifica- 

 tion in almost any desired direction. But as variations mani- 

 festly useful or pleasing to man appear only occasionally, the 

 chance of their appearance will be much increased by a large 

 number of individuals being kept. Hence, number is of the 

 highest importance for success. On this principle Marshall 

 formerly remarked, with respect to the sheep of parts of 

 Yorkshire, "as they generally belong to poor people, and are 

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

 other hand, nurserymen, from keeping large stocks of the 

 same plant, are generally far more successful 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 favourable. When the 

 individuals are scanty, all will be allowed to breed, whatever 

 their quality may be, and this will effectually prevent selec- 

 tion. 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 straw- 

 berry had always varied since it was cultivated, but the slight 

 varieties had been neglected. As soon, however, as gar- 

 deners picked out individual plants with slightly larger, ear- 

 lier, or better fruit, and raised seedlings from them, and again 



