400 CONSERVATIVE ORGANS. [LECT. VIII. 



life of the entire plant. If a longitudinal section 

 of a twig be examined at this time, although the 

 pith be, generally speaking, a dry spongy 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 

 vital energy of the buds is extended around them 

 to a certain degree, maintaining the lateral com- 

 munication 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 forwards, into the light and 

 air, the young branch with its leaves and flowers. 

 On examining now the connexion of the shoot with 

 the stem or branch, we find it no longer, an iso- 

 lated individual, but seated closely upon the me- 

 dullary sheath of the parent; and the alburnous 

 matter which is deposited between its bark and 

 pith, continuous with that thrown out from the 

 liber of the old bark, already giving origin to a 

 ligneous layer, that forms both a connecting vin- 

 culum between the tree and the new branch, and 

 a support to the latter in its projecting position. 



I suspect that Hill confined his examination 

 of buds to the autumn, and before they were 

 ready to open in spring; and thence he was led 

 to adopt the opinion that the branch originates 



