474 CASUALTIES OF VEGETABLES. CHAP. XII. 



hares, rabbits ; by lightning ; by weight of fruit ; 

 or by violent storms of wind, hail, snow. 



SUBSECTION I. 



Some- Incision. Incisions are sometimes necessary to 



^ e health of the tree, in the same manner perhaps 

 as Bleeding is necessary to the health of the animal. 



plant. The trunk of the Plum and Cherry-tree seldom ex- 

 pand freely till a longitudinal incision has been 

 made in the bark ; and hence this operation is often 

 practised by gardeners. If the incision affects the 

 epidermis only it heals up without leaving any scar ; 

 if it penetrates into the interior of the bark it heals 

 up only by means of leaving a scar ; but if it pene- 

 trates into the wood, the wound in the wood itself 

 never heals up completely ; but new wood and bark 

 are formed above it as before. 



SUBSECTION II. 



Employed Boring. Boring is an operation by which trees 

 are ft en wounded for the purpose of making them 

 part with their sap in the season of their bleeding, 

 particularly the Birch-tree and American Maple. A 

 horizontal or rather slanting hole is bored in them 

 with a wimble, so as to penetrate an inch or two into 

 the wood, from this the sap flows copiously; and 

 though a number of holes is often bored in the same 

 trunk, the health of the tree is not materially if at 

 1 



