LECT. VIII.] ORIGIN OF BRANCHES. 401 



from the vessels of the medullary sheath, which, as 

 I have already remarked, he termed the corona, 

 holding it to be the most important part of the 

 plant *. The difficulty of explaining the appear- 

 ance of adventitious buds on such a supposition, 

 led to the rejection of his theory ; and I am sur- 

 prised to find that a late ingenious writer -f- sup- 

 ports the fallacy of it by this remark : " it is no- 

 torious, that trees in which not only this first 

 circle, but almost every other circle of vessels 

 has perished, produce leaves and shoots from 

 the trunk where the bark is entire, as this au- 

 thor himself admits, p. 44 of his work : " for, in- 

 dependent of the absurdity of imagining that the 

 life of the tree could be supported at all, if every 

 circle of vessels had perished, the objection dis- 

 plays an unaccountable neglect of investigation. 



I trust enough has been demonstrated, in ,the 

 dissections laid before you, to establish the fallacy 

 of Hill's theory; but on different grounds from 

 those taken up by the author above quoted ; and 

 I have now only to explain how the appearance of 

 adventitious buds on hollow trees does not militate, 

 in any degree, against the theory I have advanced. 

 In doing so, I must recur to my position, that 

 every bud originates with the branch or stem on 



* Hill on the Construction of Timber, p. 21 . 



f Mr. Ellis : see the article Vegetable Anatomy^ in the Sup- 

 plement to the Uh and 5th editions of the Encyclopedia Bri- 

 tannica t vol. i. Part 2. p. 335. 



VOL. I. D D 



