TREATMENT OF WOUNDS 29 



plete dressings is that they do not to any extent 

 prevent the checking of the wood, even when they 

 are frequently renewed. They cannot in any way 

 fill or bridge over cracks. Checking continues, 

 though slowly, for an indefinite period. Ulti- 

 mately, the cracks get so large, if they are not 

 covered over, that water gets into them and, freez- 

 ing, tends to break out bits of the wood, thus ex- 

 posing the unimpregnated inner regions. For 

 this reason chemical preservatives, as distin- 

 guished from dressings which produce a mechani- 

 cal covering, have not proved successful perma- 

 nent applications for wounds. 



Of these materials which do actually fill and 

 cover the wood, paint is probably the most used. 

 Pure white lead and linseed paint makes a very 

 good dressing for moderately small wounds, espe- 

 cially if the wood is dry when the paint is applied. 

 Its effectiveness is much increased if a second ap- 

 plication is made after the first checking has taken 

 place. Paint seems especially suitable for ordi- 

 nary orchard practice, where the wounds are not 

 large or inaccessible and healing is fairly rapid. 

 It would not do to ignore Prof. Bailey's judgment 

 in such a matter. " My conclusion is," he says, 

 " after having had the question in mind for a 

 decade, that a heavy application of lead paint is 

 the best all-round dressing for common pruning 

 wounds." The tree repairer, however, has often 



