88 



much as if a bolt of iron was passed into 

 the tree. 



De Candolle remarks, that as the 

 diameter of tlie branch is at first ex- 

 tremely small, but increases annually^ 

 each year the stem encloses a larger 

 circumference ; and that part of the branch 

 which is enclosed is in the form of a cone, 

 its base at the bark, and diminishing 

 inward towards the pith. The outer 

 part of the branch is in the form of 

 a cone, its base at the bark, diminishing 

 outward. This is very ingenious ; but 

 no such actual internal cone exists. The 

 medullary rays and longitudinal woody 

 fibres of the new annual growth of the 

 branch are prolonged, and run vertically 

 down that part of the stem of the tree 

 which is below the branch ; so that it is 

 only the grain of the centre part of the 

 branch which runs across the grain to the 

 centre of the tree. It then runs down the 



