LETTER XIII. 



137 



at North Stoneham. " A large branch was broken 

 off, laying bare the interior of the stem to a consider- 

 able extent. The tree still lived, and from the upper 

 branches distinct roots were sent downwards, which 

 gradually covered a large portion of the wound. The 

 growth was traced in a downward direction, and the 

 root-like appearance of the fibres was quite evident." 



5. Further, examine carefully the naked trunk of an 

 Oak, or other hardwood tree, which has been felled 

 and stript of its bark, particularly after it has lain some 

 time exposed to the weather. Look at the general 

 course and disposition of the fibres, and particularly 

 at the way in which they comport themselves where 

 the main branches join the trunk, or where two 

 branches meet, or in the neighbourhood of hollows 

 or clefts ; and I think you will be satisfied that I 

 spoke truly in my last letter (§ 14), when I said, that it 

 is by no means a full account of those fibres to describe 

 them as formed in situ, and evolved by an elongation 

 of certain of the cells of the Cambium-layer. Were 

 this all that could be said of them, we might expect to 

 find the fibres disposed in tolerably straight lines and 

 perpendicularly to the axis* But what do we actually 

 see ? We see the fibres, as a whole, pursuing a spiral 

 course downwards — winding round the trunk ; — mean- 

 dering, however, and twisting in all directions in their 

 course to the ground, — turning round knots or other 

 obstacles that lie in their way — even ascending to steer 



