SUGGESTIONS. 33 



been found of service against canker, whether operations upon 

 the roots or the foliage, are all such as are calculated to 

 establish or replace the tree in circumstances favourable to 

 its general thriving, healthy condition. 



This suggests the idea that canker may be the result of a 

 general constitutional debility of the tree, not occasioned by 

 any one cause or set of causes, but resultant from -all and any 

 circumstances unfavourable to the healthy growth of a tree ; 

 and it is a question whether the same may not be thought 

 of the peculiar diseases of other trees, the peach, the pear, 

 the plum, the sycamore, and perhaps even of the rot of the 

 potato. 



2* 



