598 THE BEGINNINGS OF LIFE. 



changes by which the peach-branch is metamorphosed 

 into a nectarine-branch. The possibility of the occur- 

 rence of the molecular change which occasions this 

 metamorphosis is, moreover, by no means limited to 

 the buds of the peach-tree. For, as Mr. Darwin tells 

 us, ' nectarines have likewise been produced from the 

 stone of the peach, and, reversely, peaches from the 

 stone of the nectarine.' And even this is not all, since 

 Hhe same flower-bud has yielded a fruit one half or one 

 quarter a nectarine, and the other half or three quarters 

 a peach.' 



Again, as a proof that at rare intervals, what appear 

 to be totally distinct specific forms may arise from the 

 embryo of a given species of animal, we may cite 

 the m.ost remarkable instance ^ of the appearance of the 

 ^ black-shou-ldered peacock ' {J^a^vo nigripennis) amongst 

 Sir J. Trevelyan's flock, composed entirely of the 

 common species. The new form increased ' to the ex- 

 tinction of the previously existing breed,' and it is 

 regarded by several of our best authorities as a distinct 

 ^species': and yet this black-shouldered peacock has 

 been known to have had a similarly independent origin 

 five times, in England. There is no real reason, 

 therefore, why such changes should not also at times 

 occur with plants or animals living in the wild state. 

 Mr. Murphy aptly remarks ^ : — '^ It may be true that 



^ Darwin's ' Animals and Plants under Domestication,' vol. i 

 p. 290. 



2 ' Habit and Intelligence,' vol. i. p. 344. 



