Arsenical Poisoning oe Fruit Treks. 25 
juice that exudes is ill smelling and the area is continuous with the 
corroded crown. The whole section of a root may be involved or 
only the upper portion of it. There is frequently as sharp a line 
showing the limits of the attack on the roots as is shown by these 
patches on the trunk. This illustrated by Plate VI, rep- 
PLATE VI. 
resenting the root of an apple tree, the further portion of which was 
perfectly healthy in appearance, which is also shown in the photo¬ 
graph. It may be of sufficient interest to justify a statement that 
this root was cut from the tree last May and the tree was prac¬ 
tically dead this fall when I last saw it. I have found in such 
trees from 12.5 parts in the woody tissue to 24.65 parts of arsenic, cal¬ 
culated as arsenic acid, in the disintegrated bark. 
Prof. C. S. Crandall, of the University of Illinois, formerly hort¬ 
iculturist of the Colorado Experiment Station, writes me that their 
chemist, Mr. O. S. Watson, obtained in .camples of disintegrated bark 
which he collected while on a visit to this state 1.8 and 15.8 parts of 
arsenic per million. 
In a sample of disintegrated bark collected from the crown of 
some pear trees 24.71 parts of arsenic per million, calcidated as arsenic 
acid, were recovered. In the woody tissue of an apple tree root which 
we know was killed by sodic arsenite, 24.02 parts of arsenic acid were 
recovered. The inner portion of the bark on the pear tree is for the most 
part s + id intact and healthy but the bark is in many places very thin and 
occasionally we find it eaten entirely through and the underlying sao 
wood already attacked. The explanation that I offer for this condi¬ 
tion is that the soray has been aonlied heavily enough to run down 
the trunk and cobect around the crown of the tree just as the arsenic 
codected under the bands described by Dr. Bradbury. It has been 
solub’e enough to saturate the bark to the extent stated, 24.71 parts 
