1SG 
TAPERS AND PROCEEDINGS OF THE HORTICULTURAL SOCIETY. 
and bleed, the wound expands, and the virus 
gradually corrodes the adjoining parts, until 
it encircles the branch and destroys it. The 
cankered part, when cut transversely, exhibits 
the pith, alburnum, and rind, all tainted by 
the vitiated sap, which may be traced from 
the point where it takes its rise by its dis- 
coloured tint, to the wound whence it issues 
and forms gum ; it is rarely confined to a few 
parts, but circulates through and affects the 
whole system to the extremities. Gum is the 
consequence, either of the plant being propa- 
gated from a diseased stock ; or, if healthy 
originally, of the tree being planted in an un- 
suitable soil or situation ; old gardens long 
worked, exhausted of that freshness so con- 
genial to the peach, and saturated with acrid 
and corroding manures, rarely afford healthy 
peach trees ; cold clayey ground, retentive of 
moisture, and such as have a sour or ferru- 
ginous substratum, which chills and cankers 
the roots, are equally pernicious to the peach 
tree ; on such it generally throws out strong 
spongy and ill-ripened shoots during summer, 
which possessing a superabundance of crude 
watery juices, are frost-bitten in winter, and 
gum and perish the ensuing season. Cold raw 
summers, also, in which the mean heat is 
below the temperature necessary for the peach 
tree to elaborate its sap, or enable its vessels 
to perform their secretions perfectly, always 
tend to produce gum and canker in fruit trees. 
The disease also proceeds from wounds, or other 
external injuries, of which the peach tree is 
susceptible ; in all cases, except that of 
wounds, topical applications fail in producing 
any permanent good effect ; but where they 
are resorted to, the edges of the wound should 
be pared to the quick, all the carious parts 
cleaned out, and the whole covered with some 
durable composition, which will adhere and 
effectually exclude the air and moisture, in 
which, I believe, consists all the efficacy that 
any application can possess. One of the best, 
and most readily provided, is a mixture of tar 
and powdered charcoal, sufficiently fluid to be 
laid on with ease: perhaps as charcoal has 
been found a powerful antiseptic, it may have 
some effect in counteracting a tendency to 
putrefaction in the wound. The apricot, 
plum, and cherry, are also subject to gum ; 
to the first it frequently proves destructive, 
Tut to the others it is less injurious. — Canker. 
Of all the diseases to which fruit trees are 
subject, the most injurious is the canker. In 
the pear and apple, proceeding from the same 
causes as gum in the peach, it resembles it in 
its progress, and is equally fatal in its ter- 
mination. From the strong similitude their 
features present in common, we may consider 
them as diseases of the same class, though 
altered in their symptoms by the peculiar 
organization of the different plants, and the 
same remedies and precautions which have 
been prescribed in the one case are generally 
applicable in ihe other. The pear and apple, 
however, possess the advantage of having some 
varieties much hardier and less liable to canker 
than others ; these, though in general of in- 
ferior quality, may, in case of the failure of 
choice sorts, be grafted on them, and succeed 
perfectly well where the others would perish. 
Being of opinion that no small proportion of 
both gum and canker, which are unfortunately 
so widely extended, have proceeded from the 
trees having been incautiously propagated from 
diseased stocks, by which means many valuable 
varieties of fruit have been brought into un- 
deserved disrepute, I feel that I cannot too 
strongly impress on the mind of the cultivator 
the necessity that exists for his using the 
utmost precaution in the choice of scions for 
grafting or budding, and that none should be 
employed but such as are taken from trees 
perfectly healthy and free from these com- 
plaints, otherwise they will be most certainly 
transferred, and the diseases in that case per- 
petuated. Independent of any other cause, 
some sorts are, in consequence of their con- 
formation, diseased from the seed ; such, no 
skill or circumstances will ever render healthy. 
— Age. Old age, though not properly a disease 
in fruit trees, but the last stage of existence, 
which, in common with that of all other 
organized beings, contains the germ of decay 
in its bosom from its birth, yet, as it is acce- 
lerated by adventitious circumstances, so may 
it also be retarded by art. A tree though 
planted in the most favourable situation, and 
enjoying in youth the most perfect health, 
must, nevertheless, experience in time in- 
firmities proceeding, amongst other causes, 
from the increasing difficulty with which the. 
head draws its supplies of nourishment from 
the roots, as the distance between its ex- 
tremities becomes more lengthened, and its 
vessels become more rigid and obstructed ; but 
by grafting the young shoots on young stocks, 
these defects may in a great measure be done 
away, a new vigour imparted to it, and its ex- 
istence prolonged to an indefinite term, when 
compared with that of human life. — Letter by 
Mr. J. Robertson. 
[Although these remarks were made as long 
since as 1821, they contain many valuable 
suggestions applicable to the present day.] 
Growing Melons on open Borders. — 
About the middle of March, the seeds for the 
first out-door crop are sown, and placed in a 
cucumber or other frame, where there is a 
tolerable heat. They are potted and treated 
in the usual way, till the final planting out. 
The first or second week in May, I prepare a 
bed on a south or south-west border, by 
