MR. A. MrREAT ON GRAFTING AND BUDDING. 
119 
and almost hermetically sealed in by the deposits of wood which 
have taken place subsequently to the union of the graft ; and 
although I have called it an ulcer, it is only so in the sense of 
being a source of decay ; there is no active or malignant principle 
at work ; it is merely the gradual decay of a perishable body 
which is situated in the heart of the timber. 
It may be asked, too, whether this decay in the heart really 
does any damage other than weakening the branch or stem at 
the point where it exists ; for it cannot be disputed that to that 
extent at least it must be injurious. Is the heart of the stem of 
a tree of any use to ifc except for tlie support and solidity which 
it gives it ? "We see old piped trees flourishing away after all the 
heart is gone and nothing left but a thin rind. True, the flourish- 
ing is not so vigorous as in a younger and more solid tree. No 
great sturdy arms are thrown out ; and the foliage is limited to 
a few clustered scrubby twigs. But it does not follow that this 
weakness of growth is due to the tree being piped. In such 
cases, we must remember, that tree has generally been growing 
in the same ground for perhaps hundreds of years, exhausting 
all the ingredients of the soil which are suitable for elaboration 
into its sap and fibre — and that if we remove the tree and plant 
another of the same kind in its place, it grows no better than the 
old one, seeming to show at all events that it is not the mere 
absence of pith and heart-wood in the old tree which has caused 
the declension in its vigour of growth. 
The principles of physiology, therefore, would rather seem to 
say that in all those cases (such as fruit-trees, roses, &c.) where 
the acquisition of solid timber (whether for the support of the 
tree or for the uses of man) is not the principal object, grafting, 
although attended by decay, is not attended with consequences 
injurious to the purposes for which the tree is cultivated. But 
where timber is the object, as in forest-trees, the case is difl"erent. 
The decay imbedded at the base of the stem, gives an element of 
weakness to the tree at the very point where the leverage of the 
wind is strongest, and exposes it to be snapped off by the root. I 
do not think it can be said to be injurious to the growth of the 
timber in other respects ; for immediately above the graft the 
timber is deposited in a solid and continuous stream ; and I see no 
reason why the tree in all other respects should not be as good as 
an unworked plant. Still we all have a prejudice in favour of 
seedling trees ; and I think that the liability of grafted plants to 
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