Chap. XL 



OF THE CHAPTER. 



411 



To my surprise I hear from Mr. Salter that he brings the 

 great principle of selection to bear on variegated plants propa- 

 gated by buds, and has thus greatly improved and fixed several 

 varieties. He informs me that at first a branch often produces 

 variegated leaves on one side alone, and that the leaves are 

 marked only with an irregular edging or with a few lines of 

 white and yellow. To improve and fix such varieties, he finds 

 it necessary to encourage the buds at the bases of the most 

 distinctly marked leaves, and to propagate from them alone. 

 By following with perseverance this plan during three or four 

 successive seasons, a distinct and fixed variety can generally be 

 secured. 



Finally, the facts given in this chapter prove in how close 

 and remarkable a manner the germ of a fertilised seed and the 

 small cellular mass forming a bud resemble each other in func- 

 tion, — in their powers of inheritance with occasional reversion, — 

 and in their capacity for variation of the same general nature, in 

 obedience to the same laws. This resemblance, or rather identity, 

 is rendered far more striking if the facts can be trusted which 

 apparently render it probable that the cellular tissue of one 

 species or variety, when budded or grafted on another, may give 

 rise to a bud having an intermediate character. In this chapter 

 we clearly see that variability is not necessarily contingent 

 on sexual generation, though much more frequently its con- 

 comitant than on bud-reproduction. We see that bud-variability 

 is not solely dependent on reversion or atavism to long-lost 

 characters, or to those formerly acquired from a cross, but that 

 it is often spontaneous. But when we ask ourselves what is the 

 cause of any particular bud-variation, we are lost in doubt, being 

 driven in some cases to look to the direct action of the external 

 conditions of life as sufficient, and in other cases to feel a pro- 

 found conviction that these have played a quite subordinate part, 

 of not more importance than the nature of the spark which 

 ignites a mass of combustible matter. 



END OF VOL. I. 



