286 The Principles of Fruit-growing. 
eventually becomes plant-food by being washed off 
onto the soil, though the chief value of the wash is 
no doubt the softening and loosening effect which it 
has on the bark. 
Another means of releasing the pressure upon 
hide-bound trees is to slit the bark the entire length 
of the trunk or hide-bound portion. This is done 
by simply thrusting the point of a knife through the 
bark until it strikes the wood, and then drawing the 
blade down the entire length of the portion to be 
treated. When the knife is withdrawn, the slit is 
scarcely visible; but after a time the slit widens, 
as the tree begins to expand. This method is to be 
advised only as an extreme resort, for it is better to 
keep the bark fresh and elastic by good tillage and 
by the use of washes; but the slitting is of no 
damage to the tree, as a rule. The washing also has 
the additional advantage of killing various insects 
and their eggs which may be in or about the bark. 
Spraying with Bordeaux mixture will kill the lichen 
or “moss” on the trunks. 
Scraping trees.—The outer layers of bark of any 
tree gradually die and peel off, as the tissue grows 
upon the inside. This old, rough bark is of no 
direct use to the plant, but it probably affords some 
protection to the tender tissues within. It also af- 
fords a lodgment for insects and fungi. Trees which 
are kept in a good condition of growth and which 
are watched carefully, will need very little attention 
in the removing of the bark, but if the shaggy bark 
accumulates to any great extent, it is well to serape 
