470 CASUALTIES OF VEGETABLES. CHAP. XII. 



being put back into their natural position, and well 

 propped up. Especially the cure may be expected 

 to succeed if the fracture happens in the spring ; 

 but it will not succeed if the fracture is accompanied 

 with contusion, or if the stem or branch is large ; 

 and even where it succeeds the woody fibres do not 

 contribute to the union, but the granular and herba- 

 ceous substance only which exudes from between 

 the wood and liber, insinuating itself into all inter- 

 stices and finally becoming indurated into wood. 



SUBSECTION V. 



Pruning. Wounds are necessarily inflicted by 

 the gardener or forester in the pruning or lopping off 

 of superfluous branches, but this is seldom attended 

 with any bad effects to the health of the tree, if done 

 by a skilful practitioner ; indeed no further art is 

 required merely for the protection of the tree be- 

 yond that of cutting the branch through in a sloping 

 direction so as to prevent the rain from lodging, 

 In this case the wound soon closes up by the 

 induration of the exposed surface of the section, and 

 by the protrusion of a granular substance, forming a 

 sort of circular lip between the wood and bark ; and 

 hence the branch is never elongated by the growth 

 of the same vessels that have been cut, but by the 

 protrusion of new bu,ds near the point of section, 



