CHAP. IV.J 
LAYERS. 
75 
and at others a wire is twisted firmly round the 
shoot, so as to pinch in the bark; or a knife 
or any sharp instrument is passed through 
the branch several times in different direc¬ 
tions : in short, any thing that wounds, or in¬ 
jures the shoot, so as to throw an impediment 
in the way of the returning sap, and yet not to 
prevent the passage of the sap that is ascend¬ 
ing, will suffice. 
Layering is a very common mode of pro¬ 
pagating plants: and in nurseries often every 
shoot of a tree or shrub is thus wounded and 
pegged down. In this case, the central root 
is called a stool, from the verb, to stole , which 
signifies the power most deciduous trees pos¬ 
sess, of sending up new stems from their 
roots when cut down. The seasons for per¬ 
forming the operation of layering are during 
the months of February and March, before 
the new sap begins to rise, or in June or 
July after all the summer supply of ascending 
sap has risen; as at these seasons there is no 
danger of injuring the tree by occasioning an 
overflow of the ascending sap, which some¬ 
times takes place when the tree is wounded 
while the sap is in active motion. In most 
