52 BIOGRAPHY. 



fury of the tempest without, 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 forewarned of the coming ruin. 

 The disease which causes the destruction takes place in 

 the oak ; but more frequently in the sycamore, and most 

 commonly of all in the ash. We will select this last tree 

 by way of elucidation. 



" Often, when arrayed in all the bloom of vegetable 

 beauty, the ash-tree is seen to send forth from its bole, or 

 from some principal branch, a small fungus, which, during 

 the summer, increases to a considerable size. It ripens in 

 the autumn, and falls to the ground when winter's rain 

 sets in. The bark through which this fungus sprouted is 

 now completely dead, though it still retains its colour ; and 

 that part of the wood from which it proceeded is entirely 

 changed in its nature, the whole of its vitiated juices 

 having been expended in forming and nourishing the 

 fungus. Nothing remains of its once firm and vigorous 

 texture. It is become what is commonly called touch- 

 wood, as soft and frangible as a piece of cork, which, when 

 set on fire, will burn like tinder. In the meantime, the 

 tree shows no sign of sickness, and its annual increase 

 goes on as usual, till at last the new swelling Avood closes 

 over the part from which the funn;us had grown, and all 

 appears to go on right again. But ere the slow process 

 arrives at this state the titmouse or the woodpecker will 

 have found an entrance and a place of safety for their in- 

 cubation. They quickly perforate the distempered bark, 

 and then the tainted wood beneath it yields to their 

 pointed bills, with which they soon effect a spacious 

 cavity. 



" Here, then, we have the whole mystery unfolded. These 



