Arsenical Poisoning of Fruit Trees. 
23 
ment of the present owner, who in many cases knows nothing about 
the earlier history of the orchard. 
In writing of these trees Mr. Whipple made the following state¬ 
ment : 
“Two seasons are required for the disease to kill the tree. The first 
season the trunk is girdled and the foliage drops early. This early ripening 
of the foliage is often the most prominent symptom and diseased trees can 
be easily picked out in the early fall. * * * The second season the tree 
starts in to leaf as the normal tree, generally setting fruit, and dies in 
midsummer, the fruit and leaves clinging.” 
This description is entirely correct, but it applies to trees in which 
the damage has already proceeded so far that we can, with a great 
degree of certainty predict how soon the tree will die. This too was 
the phase of the trouble at which we began to study it. We found 
a zone beginning just below the ground and extending down on to the 
roots where the bark had been destroyed and the underlying'tissues 
stained brown. The similarity between these conditions and those 
produced by the arsenite of soda is perfect. The destruction of the 
tissue is almost as though it had been charred by dilute sulphuric acid 
but is more complete than would be accompanied by a like coloration 
if it had been produced by this acid. I have examined a large num¬ 
ber of samples of the woody tissues of such trees, and have uniformly 
found that arsenic is present. The bark has not been used because the 
arsenical spray material might be mechanically included in it. For 
this reason the bark has in all cases been carefully removed. Further 
no dead wood which has been exposed to contact with spray material 
has been used, so that the results represent what has taken place in the 
tree itself. 
The first samples examined were roots of a pear tree in which the 
trouble had not proceeded as far as the phase described by Mr. 
Whipple, but which were not healthy; these roots contained arsenic in 
large quantities. Subsequently other pear trees and apple trees 
were examined with like results till we have examined in all eighty- 
one trees, apple, pear and peach. The results may be summed up as 
follows: in every case in which the death of the tree has been 
earned by corrosive arsenical poisoning we find the crown of the tree 
girdled, the bark below the surface of the ground is usually attached 
to the tree but is brown or black in color and its texture is wholly 
destroyed, the woody tissue of the root is colored mostly a deep 
brown and sometimes its texture too is destroyed. The wood of 
the lower part of the trunk is usually stained, though it may have no 
other sign of unhealthiness. This is in no manner similar to a 
spot of dead wood on the trunk of the tree above the crown caused by 
freezing or by a mechanical injury. The bark above the line of the 
ground is intact in most of these cases though there are some instances 
of trees resembling the one shown in Plate 2, Fig. 1, Bulletin 131, 
which, however, is not similar to ca es of winter killing with which 
any of us are familiar. The heart wood even in the limbs and branch¬ 
es is generally, but not always, of a deep brown color with a decided- 
