180 



LETTERS ON TREES. 



nature or in our ordinary conceptions of what consti- 

 tutes individuality, between two potato plants growing 

 side by side in the same garden, the one raised from 

 a seed, the other from a bud ? What real difference 

 between two Willow-trees growing together by the 

 same water-course, the one the produce of a seed, the 

 other the produce of a bud ? None certainly in those 

 respects ; and only this other difference (already 

 indicated), that the one will represent the species, 

 and this only, while the other will represent besides 

 this, its own variety of the species. But does this 

 imply any fundamental difference ? Dr Carpenter 

 does not expressly assert that it does, but he speaks 

 as if he seemed to think it did. After observing 

 that, whilst the seed " continues the species only," 

 the bud " reproduces the particular variety ; " and 

 that hence when it is desired to multiply a certain 

 kind of fruit-tree, the buds are employed rather than 

 the seeds," he adds — But this method of reproduc- 

 tion cannot he carried to an indefinite extent »^ And 

 for this reason, that " although it may not be true (as 

 stated by some) that the life of the 'graft' will only 

 last as long as that of the ' stock ' from which it was 

 taken, yet it is almost invariably found that varieties 

 of trees and plants which are thus multiplied lose their 

 vigour and ' die out,' after a certain lapse of time."* 

 8. There is I suspect a little injustice here done to 

 * Principles of Physiology, Gen, and Compar., p. 901. 



