166 



LETTERS ON TREES. 



directly or indirectly, itself producing or essentially 

 contributing to the production of the ligneous tissue 

 of the woody stem. As for the rest, the Cactus grows 

 and extends itself in the same way as trees do, — by 

 buds; and the individual growths that issue from 

 these buds are I presume equally short lived, indi- 

 vidually, as those from the buds of trees. Dr. Car- 

 penter, it is true, speaking of the aggregate stem, 

 remarks that its duration is extremely prolonged, its 

 life being very slow. But I fancy the remark is to 

 be taken in the same sense with that formerly ad- 

 verted to in this letter. 



13. As far then as these two instances go, I see 

 nothing in Dr Carpenter's strictures that militates 

 against my theory — nothing at least that is not em- 

 braced in his general statements — to the considera- 

 tion of which I shall proceed in my next letter. — I 

 am, &c. 



