60 



frequently before the tree can overcome the 

 resistance of the bark, it is materially in- 

 jured in its health, and when it fails altoge- 

 ther, dies. It may be observed, from the 

 straps on wall trees, that a very slight stric- 

 ture checks the growth of a tree orbranch ? 

 and produces canker. 



And it may be observed, that fruit trees 

 seldom bear well till they burst the bark, 

 and then they are soon after infested by the 

 vermin ; so that they never are, at best but 

 a few years, in what can be called a good 

 bearing state. 



A question has been started, whether the 

 vermin is the cause or effect of the canker? 

 The vermin certainly is not the general 

 cause of the canker, though I believe they 

 may sometimes produce it topically j nor is 



