APPENDIX. 
REMARKS ON THE DURATION OE VARIETIES OF FRUIT 
TREES. 
It was, for a long time, tlie popular notion tliat when a good 
variety of fruit was once originated from seed, it might be con- 
tinued by grafting and budding, for ever, — or, at least, as some 
old parchment deeds pithily gave tenure of land — “ as long as 
grass grows, and water runs.” 
About fourteen years ago, however, Thomas Andrew Knight, 
the distinguished President of the Horticultural Society of 
London, published an Essay in its Transactions, tending entirely 
to overthrow this opinion, and to establish the doctrine that all 
varieties are of very limited duration. 
The theory advanced by Mr. Knight is as follows : All the 
constitutional vigour or properties possessed by any variety of 
fruit are shared at the same time by all the plants that can be 
made from the buds of that variety, whether by grafting, bud- 
ding, or other modes of propagating. In simpler terms, all the 
plants or trees of any particular kind of pear or apple being 
only parts of one original tree, itself of limited duration, it 
follows, as the parent tree dies, all the others must soon after 
die also. u No trees, of any variety,” to use his own words, 
“ can be made to produce blossom or fruit till the original tree 
of that variety has attained the age of puberty ;* and, under 
ordinary modes of propagation, by grafts and buds, all become 
subject, at no very distant period, to the debilities and diseases 
of old age.” 
It is remarkable that such a theory as this should have been 
offered by Mr. Knight, to whose careful investigations the 
* This part of tlie doctrine has of late been most distinctly refuted, and 
any one may repeat the experiment. Seedling fruit trees, it is well- 
known, are usually several years before they produce fruit. But if a graft 
is inserted on a bearing tree, and after it makes one season’s fair growth, 
the grafted shoot is bent directly down and tied there, with its point to 
the stock below, it will, the next season — the sap being checked — produce 
flower-buds, and begin to bear, long before the parent tree. 
