32 Dr Harvey's Observations on the 



any thing to do, directly, at least, with changes going on in 

 any of the other structures of the tree. 



It has thus, it is hoped, been satisfactorily made out, Jirst, 

 that the growths emanating from the buds of trees constitute 

 perfect and independent plants ; and, secondli/, that what re- 

 mains of them, after the fall of the leaves and flowers, and 

 fruit in autumn, with the single exception of the new buds, 

 ceases to be, and never afterwaixls becomes, the seat of any 

 vital action. 



And if this be conceded, it will probably be allowed also, 

 that the view which has here been taken of the nature and 

 of the natural longevity and size of trees is well-founded ; 

 that is to say, that a tree is simply a collection of annual 

 plants of the same species, the production of a series of suc- 

 cessive years, — the individual plants of each year shooting 

 up in spring from buds adherent to the persistent dead re- 

 mains of the plants of the previous year, growing as parasites 

 on these remains, putting on the characters of old age in 

 autumn, and speedily thereafter dying, having made provision, 

 however, in summer, in the form of buds, for the reproduction 

 of similar plants the following year. And that being thus 

 evolved, and thus gi'owing from year to year, and having no 

 natural limit to their increase and aggregation, there is no 

 natural limit to the age or to the size to which the tree col- 

 lectively formed by them may reach. 



The statement repeatedly made, that the persistent dead 

 remains of the plants of the previous year serve as a mechani- 

 cal support to the plants of the following year, does not appear 

 to require any explanation. With regard to the other state- 

 ment, that they serve as a temporary soil to these plants, it 

 may be observed, that the buds are always placed in intimate 

 connection with the pith or medulla of the shoots to which 

 they are adherent, and that the pith is soft and juicy in spring, 

 but in the course of the season becomes dry and shrivelled. 

 According to M. Thenars, the buds vegetate in the first in- 

 stance at the expense of the pith, deriving from it the ma- 

 terials of their development in spring. When this supply of 

 nourishment is exhausted, or at least when the buds send out 

 their own proper roots, i. e., the fibres formerly mentioned, 



