Chap. IV.] MISCELLANEOUS. 149 
culation in the winter the roots are useless in 
the winter, and if, according to Liebig, trees 
derive their nutriment from their leaves in the 
summer, the roots are useless in the summer. I 
differ in both cases. 
I have observed that, if the stem of a young 
tree grown in water is cut at the beginning 
of winter, the root immediately ceases to grow ; 
doubtless, because the stem is necessary to re¬ 
turn the sap to nourish the root. If this theory if there is a 
winter circula- 
is true, if there is a winter circulation of sap, tion, co PP ice- 
1 wood should be 
coppice-wood, hedges, and shrubs which are 
intended to shoot up again, should be cut at the 
end of winter, — not at the beginning of winter. 
If they are cut at the beginning of winter, all 
circulation of the sap must be destroyed through 
the whole winter, till the plant can shoot out 
again in the spring; since the communication 
between the wood and the bark is annihilated: 
for, in winter, the buds form the points of junc¬ 
tion between the upward current of the sap in 
the wood and the downward current in the 
bark. I imagine that this circulation and ela¬ 
boration do go on in the winter; that, in the 
early part of winter, actual new growth of the 
root is often going on; and that, during the 
