ON TREES. 
221 
off close to the bole, you would see the new acces- 
sion of wood gradually rolling over the flat surface, 
which, in time, would be entirely covered by it: 
and then the tree would be 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 extent, 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 otherwise. Their vitality is at the 
periphery, connected with 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 fury of the tempest with- 
out, taking care at the same time to exclude the 
rain, your tree will remain in vigour from generation 
to generation. The internal texture of a tree will 
perish, without any notice by which we may be 
