BIOGRAPHY. 51 



parent stem, will, in the course of time, bring utter ruin Decay of 

 on the tree. The new wood, which is annually formed, trecSm 

 cannot grow over the jutting and fractured part, into which 

 the rain enters, and gradually eats deeper and deeper, till 

 at last it reaches the trunk itself. There it makes sad 

 havoc ; and the tree, no longer able to resist the fury of 

 the tempest, is split asunder, and falls in ponderous ruins. 

 But ere it comes to this, the titmouse will enter the cavity 

 in a dry spring, and rear its young ones here. Now, if 

 the diseased or fractured branches were carefully cut off 

 close to the bole, you would see the new accession of wood 

 gradually rolling over the flat surface, which, in time, would 

 be entirely covered by it; and then the tree would l>e 

 freed for ever from all danger in that quarter. The second 

 process towards decay is exceedingly curious, and cannot 

 well be accounted for. If it takes place to a serious ex- 

 tent, no art of man can possibly save the tree ; and sooner 

 or later, according to the magnitude of the disease with 

 which it has been tainted, it will fall before the force of 

 the raging winds. Should this disease be slight, the timely 

 prevention of rain from penetrating the injured part will 

 secure the tree from further mischief. 



" I must here observe that, in animated nature, the vital 

 functions are internal ; so that, if the part within be 

 mortally wounded, death is the inevitable consequence. 

 With most trees, and with all those of Britain, it is other- 

 wise. Their vitality is at the periphery, connected with Vitality / 

 the bark, under which an annual increase of wood takes ' 

 place, so long as the tree is alive. Should, however, the 

 bark be cut away, the tree will die upwards from the place 

 where all the bark has been destroyed. Not so with its 

 internal parts. You may entirely excavate the interior of 

 a tree ; and provided you leave a sufficient strength of wood 

 by way of wall, in order that it may be able to resist the 



