596 THE BEGINNINGS OF LIFE. 



multitudes of other less complex organisms, seem only 

 explicable in accordance with such a notion 1 . 



If looked at from these points of view, we shall be 

 more fully able to appreciate the importance of many of 

 the instances cited by Mr. Darwin. One of the simplest 

 and yet most satisfactory examples is that recorded con- 

 cerning the rare and occasional production of nectarines 

 upon peach-trees, and the reverse. Speaking of the 

 peach, Mr. Darwin says 2 : c This tree has been culti- 

 vated by the million in various parts of the world, has 

 been treated differently, grown on its own roots and 

 grafted on a stock, planted as a standard, against a wall, 

 and under glass , yet each bud of each sub-variety keeps 

 true to its kind. But occasionally, at long intervals of 

 time, a tree in England, or under the widely different 

 climate of Virginia, produces a single bud, and this 

 yields a branch which ever afterwards yields nectarines. 

 Nectarines differ, as every one knows, from peaches in 

 their smoothness, size, and flavour and the difference 

 is so great that some botanists have maintained that 

 they are specifically distinct. So permanent are the 



1 In addition to the cases of repair and reproduction of lost parts 

 already alluded to (p. 88), we are now in a position to refer to others 

 occurring even in mammals. Thus it has been ascertained by M. Pey- 

 raux and M. Phillipeaux that the spleen is restored in animals after its 

 extirpation, provided a minute portion of the organ is left in situ 

 ('Ann. des Sci. Nat.,' Zool., Jan. 1867); and Dr. Carpenter ('Comparative 

 Physiology,' 4th ed. p. 480) refers to interesting cases in which in the 

 human subject the thumb and the ramus of the lower jaw were repro- 

 duced after removal. 



2 'Animals and Plants under Domestication,' vol. i. pp. 337, 339-342. 



