280 THE OBIGIN ANU 



surface, resembles a more opaque spot of a greenish 

 hue, with lines running in a direction from the centre 

 of the parent branch towards the apex of the germ. 

 These are the first traces of the spiral vessels of the 

 future branch. The cellular matter, in the part of 

 the bud above the vital speck, displays also at this pe- 

 riod a more regular form, and indications of its sepa- 

 ration into scales are already perceptible ; but the 

 whole bud is still a completely insulated body. As 

 the organization proceeds, new scales are seen sepa- 

 rating from the mass of parenchyma, the medulla en- 

 enlarges in every direction, and in autumn the whole 

 presents a pyramidal appearance ; in which state the 

 bud remains nearly stationary until the ensuing spring. 

 As the cessation of the vegetative power in winter 

 increases in a great degree the excitability of plants 

 which outlive its severity, the genial influence of spring 

 is very early visible on their buds, in which the whole 

 vital energy of trees and shrubs may be supposed at 

 this period to reside ; and it is only by the visible 

 change which rapidly occurs in them, that we can 

 pronounce upon the life of the entire plant. If a lon- 

 gitudinal section of a twig be examined at this time, 

 although the pith he, generally speaking, a dry, spon- 

 gy mass, yet, a little above and below the parts where 

 the buds appear, it is succulent and green. This can 

 be explained only by supposing that the increased vi- 

 tal energy of the buds is extended around them to a 

 certain degree, maintaining the lateral communication 

 through the pores of the cells, while these have now 

 become impervious in other parts ; and by this effect 

 a sufficient supply of nutriment is provided for the 

 bud, which, enlarging in every direction as the spring 

 advances at length, opens its scales and pushes for- 

 ward, into the light and air, the young branch with its 

 leaves and flowers. On examining now the connex- 



