186 APPLICATION OF PRINCIPLES. 



a damp atmosphere, it speedily shoots upwards into 

 a branch, and at the same time establishes itself in 

 the soil by the developement of the requisite quantity 

 of roots. In order to insure success in this operation 

 upon the Vine, it is only necessary that the eye 

 should be dormant, and that a small piece of well- 

 ripened wood should, as has been already stated, be 

 separated with it ; it will then grow in much the same 

 way and under the same circumstances as a seed. 

 There is no doubt that many plants could be thus 

 multiplied just as easily as the Vine, but it is equally 

 certain that a far larger number cannot be so increas- 

 ed. The reason of this is, probably,, that such eyes 

 are not sufficiently excitable, and that consequently 

 they decay before their vital energies are roused; 

 and, in addition, that they do not contain within 

 themselves a sufficient quantity of organisable matter 

 upon which to exist until new roots are formed, capa- 

 ble of feeding the nascent branch. 



Mr. Knight's explanation of this, although in part 

 applicable to cuttings only, yet seems to deserve 

 being introduced in this place. " Every leaf-bud 

 is well known to be capable of extending itself into a 

 branch, and of becoming the stem of a future tree ; 

 but it does not contain, nor is it at all able to prepare 

 and assimilate, the organisable matter required for its 

 extension and development. This must be derived 

 from a different source, the alburnous substance of 

 the tree, which appears the reservoir, in all this tribe 

 of plants, in which such matter is deposited. I found 

 a very few grains of alburnum to be sufficient to sup- 



