40 OF THE BARK. 



is accomplished by each new layer, added to the bark 

 internally, spreading a little beyond the edge of the pre- 

 ceding layer. The operation of closing the wound goes 

 on the more slowly, as the wood underneath, from ex- 

 posure to the air, has become dead, and frequently rot- 

 ten, proving an incumbrance, which though the living 

 principle cannot in this instance free itself from, it has 

 no power of turning to any good account. If, however, 

 this dead wood be carefully removed, and the wound 

 protected from the injuries of the atmosphere, the new 

 bark is found to spread much more rapidly ; and as ev- 

 ery new layer of bark forms, as will be proved in the 

 next chapter, a new layer of wood, the whole cavity, 

 whatever it may be, is in process of time filled up. 



This operation of Nature was turned to great advan- 

 tage by the late Mr. Forsyth of Kensington gardens, 

 the history of whose experiments is before the public. 

 Under his management many timber trees, become en- 

 tirely hollow, were filled with new wood, and made to 

 produce fresh and vigorous branches ; and pear-trees 

 planted in the time of King William, and become so de- 

 cayed and knotty as to bear no fruit worth gathering, 

 were by gradual paring away of the old wood ai d bark, 

 and the application of a composition judiciously con- 

 trived to stick close and keep out air and wet, restored 

 to such health and strength as to cover the garden walls 

 with new branches bearing a profusion of fine fruit. 

 These experiments have passed under my own actual 

 observation, and I am happy to bear testnnony to the 

 merits of a real lover of useful science, and one of the 

 most honest and disinterested men I ever knew. 



