Philosophical Character of Decandolle. 239 



The former, such as the misletoe, may live on several diffe- 

 rent sorts of trees, because its own leaves enable it to bring 

 about the requisite changes in the juice which it imbibes ; but 

 the latter are generally confined to plants of the same genus, 

 or at most of the same natural family, since they possess no 

 organs adapted for modifying the quality of the sap, so as to 

 suit it to their own purposes. 



Another question upon which new light appears to have 

 been thrown by the writings of M. Decandolle, although many 

 probably are not aware of the source from whence their pre- 

 sent notions on this subject have been derived, relates to the 

 indefinite duration of the life of a tree, as contrasted wdth the 

 definite term of existence which nature has prescribed to every 

 animal. 



The former is destroyed merely by the accidents and dis- 

 eases contingent upon the peculiar circumstances under which 

 it is placed ; the latter, if it were not cai'ried off prematurely 

 by the maladies to which it is exposed, would nevertheless at 

 length perish from old age alone. 



This distinction between a plant and an animal, which at 

 present may appear to follow as a natural consequence from 

 the fact, that, agreeably to the views of modern botanists, a 

 plant is to be regarded, not as an individual, but as an aggre- 

 gate of individuals, each bud being a new being, grafted upon 

 the branch from which it issues, was warmly disputed when 

 Decandolle first alluded to it in 1805. 



Its universal admission at the present time affords a satis- 

 factory proof, that the philosopher who sets out with sound 

 principles, and is capable of deducing correct inferences from 

 them, may often live to see those very opinions, which, when 

 he first broached them, appeared to others the most paradoxi- 

 cal, take such deep root in the public mind, that their paren- 

 tage shall be forgotten by the majority of those who adopt 

 them as their own. 



I next proceed to notice two points discussed in these vo- 

 lumes, upon which the conclusions arrived at by our author 

 do not meet with such general concurrence amongst physiolo- 

 gists. 



I will allude, in the first place, to his opinions with respect 

 to the descending sap, on which subject he adopts the views of 

 the older botanists, and nuvintainsthat nourishment, in a li<{iu(l 



