CHAPTEE X. 



VARIATION UNDER DOMESTICATION. 



"We can anticipate the time when the earth will produce only 

 cultivated plants and domestic animals ; when man's selection shall 

 have supplanted ' natural selection/ and when the ocean will be the 

 only domain in which that power can be exerted, which for countless 

 cycles of ages ruled supreme over all the earth." 



WALLACE, '\ Natural Selection" p. 326. 



IN Nature, variation usually takes place gra- 

 dually and imperceptibly, or rather, perhaps, 

 we lack both time and opportunity to trace its 

 course, and call many forms species which we 

 should probably class as mere varieties, if we 

 were better acquainted with their history. But 

 in any case, variation takes place much more 

 rapidly, and to a much greater extent among 

 domesticated animals and cultivated plants than 

 among those in a state of nature. Many of the 

 former vary in almost every conceivable direc- 

 tion in the most marvellous manner, and to 

 such an extent that systematic naturalists, and 

 especially botanists, are compelled to leave them 

 almost entirely out of their consideration. 



