Arsenicai, Poisoning of Fruit Trees. 19 
my conviction that many trees have been killed by arsenic and that 
others are hopelessly sick. I will give some reasons for my belief. 
First, it is a well-known fact that soluble arsenical compounds will 
kill plants. It has been found that Herbicide, a preparation found 
on the market, is essentially a solution of an arsenical compound. 
Both white arsenic and arsenic acid have been shown by various 
experimenters to be deleterious even when present in very small 
quantities, one part per million in solution. Second, I took some 
greenhouse plants, coleuses, daisies and geraniums in two and a 
quarter and three inch pots and added from 0.05 to 0.5 grams, 
approximately from 3-4 of a grain to 7.5 grains, of sodic arsenite 
and the smallest amount used sufficed to kill the plants. Third, 
I know of two trees, one killed outright, at least this is the testi¬ 
mony of the owner, there is nothing but the stump left at the present 
time, and the other partially killed. It was my good fortune to see 
this tree in October last when the affected limb was still on the tree 
with the dead and blackened leaves clinging to it. Inquiry elicited 
the statement that it had been killed by arsenic as the other tree 
had. In the case of the tree that had died and been removed, they 
had made arsenite of lime under it or near it and had probably 
spilled the arsenite of soda. In the case of the tree, one limb of 
which was dead, they had been more careful with their sodic ar¬ 
senite, having some left over they determined to get rid of it and 
emptied it into the irrigating ditch near the tree; this was one day 
in June—two days later the limb was sick. I saw it in October 
when'the limb was dead and had the appearance of having been 
dead for some time, and again in April last. In the meantime the 
limb had been cut off but was still lying beside the tree as shown in 
Plate VI. Mr. Whipple and I measured the distance from the 
trunk of the tree to the irrigating ditch shown in the foreground of 
Plate V 1 ., an.'] found it to be 12 feet. An examination of this tree 
showed that a section of the bark from the base of the trunk up 
into the big limb was brown, sunken and in appearance like the bark 
in the trunks of the affected trees. The wood beneath this bark 
was rVad and colored browii, well shown in Plate VII., lower Fig. 
2, which shows that nearly the whole section of the limb was involved, 
and that the bark was sunken and dead. The condition below the 
surface of the ground was even still more striking for the bark was 
destroyed and the little that remained was very dark, in places, 
black. We dug out this root, following it to the irrigating ditch, 
to the point where the sodic arsenite had been emptied. Two or 
three feet from the ditch, the root had divided into five branches 
or rootlets. These were black and brittle. Following these toward 
the trunk, we could trace the effect of the arsenite by two sections 
of the bark, one on the upper and the other on the lower side of the 
root, which had been destroyed and the wood beneath them killed 
