6 Mr. Fohn Flower. 
perhaps, here to explain, for the benefit of those who have not 
studied botany, how it is that trees like the horse-chestnut 
grow and are nourished. The materials by which the tree is 
nourished are contained in the sap, which may be termed the 
blood of the tree, and which passes up, from the root to the 
branches, through the sap vessels, which lie immediately under 
the outside bark, and between that and the solid wood of the tree. 
The solid wood, again, is increased in diameter every year, by 
the addition of a layer of wood, which is formed by the sap 
vessels, and in this way the tree increases annually in bulk. 
If we bear these facts in mind, we shall have no difficulty in 
seeing exactly what has happened in the tree which we are 
considering. ‘The chain having been placed round it, all went 
well until, by the growth of the tree, the chain began to get 
tight; then it began to press hard upon the bark and, as a 
necessary consequence, upon the sap-vessels under it. This 
stopped the free circulation of the sap to the upper boughs, and 
the result was that the upper part of the tree got weak and 
shabby, it being in fact, half starved. Ifthe chain had pressed 
equally on all parts of the trunk at the same time, as a broad 
iron band would have done, in all probability the upper part of 
the tree would have died outright ; but, having arough outline, the 
chain was not able to stop the flow of the sap altogether, and 
so some portion of it managed to get past the chain and kept 
the upper boughs alive. The trunk, therefore, continued to 
grow, whilst, on the other hand, the chain remained stationary, 
and so, by degrees, the solid wood was formed completely over 
the chain, and then, the full supply of sap having been restored, 
the upper part of the tree was gradually recovering itself when 
it was cut down. I have cut a hole in the wood where the 
chain is nearest to the surface, and through that hole the chain 
can be seen. The position which it occupies can be seen very 
well in two ways—horizontally by the scar made in the bark 
when it grew over the chain, and by the different colour of the 
wood of the trunk, as seen from above; the dark part of the 
wood corresponding to the part which is enclosed within the 
chain, and the brighter part to that which is outside of it. At 
the nearest point it is about an inch from the edge of the wood, 
but in one place it must be embedded to a depth of four or five 
inches. The vigorous boughs which sprung out of the trunk 
a short distance below the chain were formed because the sap 
was compelled, by its nature, to employ itself in the formation 
of new wood, and, being unable to get up to the top of the tree, 
it expended its energy in throwing out these boughs as close 
as possible to the point where the free flow of the sap was 
obstructed by the chain. These, therefore, took to themselves 
more than their proper share of the sap, increased rapidly in 
