Arsenical Poisoning oe Fruit Trees. 7 
The Trunk of the Tree. 
The trunk frequently shows no effect of the trouble above the 
, • 1 t ^ ^ pear trees. Apple trees some¬ 
times show, m such cases, chocolate brown spots on the trunk 
of the tree On removing the bark, its inner side beneath these spots, 
as well as the underlying tissues, present a mottled appearance The 
cambium layer is, in these cases, not darkened or discolored except 
in these spots; the bark is not loosened or at this time dead but it soon 
dries down to the wood. These areas often have an offensive odor. 
The Varieties Affected. 
The varieties of apples and pears in which we have found this trou¬ 
ble are so numerous that it is scarcely feasible to name them. Some 
vaiieties appear to be more sensitive in some localities while some other 
varieties are more generally affected in other localities. Mr. Whipple 
noted the fact that the Ben Davis and Gano are very sensitive to arsen- 
ical sprays. It is apparently a fact that in some localities these two 
varieties are more generally affected by this trouble than any others, in 
othei localities this is not at all true. This statement can of course 
be made of the other varieties. 
The Influence of the Age of the Tree. 
Oichards which had attained a considerable age before any arsen¬ 
ical sprays were applied to them do not seem to show the effects of the 
arsenic to the fame extent as those orchards in which the trees were 
younger when the first applications were made. I recall an orchard 
visited in company with Prof. Gillette, in which there were trees 
of very different ages, the most of the trees being of the first setting, 
now between 25 and 30 years old, but a few of them were much 
younger. We found none of the old trees which seemed to be in 
danger from this trouble, while several of the young trees were about 
to succumb to it. This by no means proves that old trees are wholly 
exempt, for I know of trees 30 years old or older that have been killed 
by this trouble. In one orchard a part of which is 25 to 27 years old, 
the rest about 14 years old, the older portion contains only a few 
affected trees, while there is quite a number of such in the younger 
orchard. 
The Influence of the Soil. 
We will make some general statements at this time, which while 
entirely adequate for our present purpose are not intended to cover 
specific features of the problem. Mr. Whipple’s statement “Soil con¬ 
ditions seem,to have no relation to the disease, as it is found on all 
kindh of soil/' seems to be wholly justified. I have found it literally 
“on all kinds of soil.” While the character of soil may modify the 
trouble, it does not determine it. I have found orchards set in most 
excellent loamy soil, well drained, irrigated with pure water, in- 
