1871. ] v L Wood. 
that the peach trees were not dying from the worms, but that these at- 
tacked them because they were dying from other causes; and it is proba- 
bly true, as a general rule, that plants in perfect health are in a condition 
to protect themselves against destructive parasites, probably because 
the salts of potash in their vessels are repulsive or even destructive 
to the parasites, which destroy the plant in the absence of this defense. 
I am not certain even that the curculio may not attack certain fruits, 
the plum for example, in consequence of deficiency of the alkali in its 
juice. 
At first my experiments were confined to the peach tree; but it may be 
remembered that I said in my communication to the Society that the 
principle was applicable as well to other fruit trees, especially the apple, 
which often refuses to bear, apparently capriciously, but probably 
from the same deficiency of potash in the soil. 
Last year I had the opportunity of testing the correctness of this sup- 
position. I happened to have two apple orchards; one of them old, per- 
haps 60 years or more, the other comparatively young, having been 
planted, 15 or 20 years since, upon a piece of ground which had previously 
been the site of an apple orchard for I presume nearly a century. Both 
of these orchards might be considered as nearly or quite barren; the old 
orchard not having borne fruit of any account for 5 or 6 years; and the 
young one having never borne at all. 
In the Autumn of 1869, I tried with these trees the same experi- 
ments as in the Autumn before I had tried with the peach trees. The 
earth was dug from around their stems to the depth of about 5 inches, 
and the excavation filled, in each case, with about half a bushel of fresh 
ashes. As regards the old orchard, a part was allowed to remain without 
treatment, soasto secure the effect of contrast. Inthe following Spring 
and Summer (1870), my expectations were fully realized. Early in the sea- 
son a striking difference was observed between the trees not treated with 
ashes and those which had been so treated. A dividing line could be observed 
between the two sections of the orchard; the trees which had been ashed 
being forward both in leaf and blossom, while the others had made little 
progress; and the same contrast was presented in the fruit; the trees left 
to themselves continuing barren, while the ashed trees were loaded with 
apples. The young orchard, which had never borne fruit of any account, 
was also made for the first time very productive. 
A similar experiment I tried on several fruit trees of different kinds in 
my garden in town. Though the ashes were applied in Spring instead of 
of Autumn, the trees in the growing season gave evidence of a similar 
result. The trees were richly covered with blossoms, which were just 
becoming exchanged for young fruit, when the famous hail storm which 
proved so destructive in this city last Summer, put an end to the experi- 
ment by stripping the trees of blossom and fruit, and to a great extent 
even of their leaves. 
Among the trees was a very old Newtown pippen tree, probably of not 
