34 
Colorado Experiment Station 
and livid. The soil at a distance of twenty-five feet from the base 
of the tree was well filled with fibrous roots of the elm tree. The soil 
showed by qualitative test that it contained an abundance of arsenic. 
There remained but one thing for me to do and that was to take 
more samples. I accordingly cut off one of the roots at a point six 
feet from the base of the tree and took a section of the root three feet 
long for a sample. I also took a small limb from the healthy appear¬ 
ing side of the tree. These samples showed the presence of arsenic in 
considerable quantities. We have in this case a tree which has never 
had any arsenic applied to it directly. It is not in any way indicated 
that the tree was injured by the lime arsenite which was mixed at 
some distance from the tree, but I do not say that it was not. I say 
only that I failed to find any proof that it was injured, and my judg¬ 
ment is that it is very doubtful whether that operation performed seven 
or nine years ago had anything to do with the present troubles, except 
as it has contributed to the general conditions. The root taken started 
out between the two little bushes near the tree, then turned to the right 
and ran straight back into the orchard. We find, that some of the 
roots show a diseased condition quite similar to conditions found oc¬ 
casionally on the trunks of the trees. We find that the woody tis¬ 
sue of the root contains arsenic and also that of the limb taken from the 
apparently healthy side of the tree. The limb which has been re¬ 
moved was dying; one of the limbs remaining on the right side of the 
tree is dead. It presented all the signs which accompany the death 
of trees killed by arsenic and arsenic is present. I have no hesitancy 
in saying that arsenic is the cause of the trouble and the death of the 
limb. This tree which has really never been sprayed, and which ap¬ 
pears to have escaped accidental poisoning but whose roots were feed¬ 
ing in a soil rich in arsenic, is dying of arsenical poisoning. 
The soil in this case is a red mesa soil somewhat clayey and at the 
same time calcareous, I would say marly, it effervesces freely with 
acids. I do not know how far it is to water, but judging from the line 
at which the seepage water breaks out below the edge of the mesa, 
twenty-five feet is a conservative depth to assume for the water plane. 
The ash of the smaller limb which the plate shows as having been 
cut off shows the presence of copper, but the presence of lead is 
doubtful. A porcelean lamp was used in incinerating the wood; so that 
there is no question but that the copper was contained in the wood; be¬ 
sides the quantity present is too big to have come from the flame of a 
Bunsen burner in the ordinary course of work. 
The virgin soil from this mesa was tested for copper, lead and 
arsenic. One hundred grams of soil failed to give a trace of lead. By 
careful manipulation we were able to establish the presence of a minute 
trace of copper, but there is a more decided quantity of arsenic 
present. The orchard soil is decidedly rich in copper and arsenic. 
It was not tested for lead and needed not to have been for arsenic, for 
we know that the arsenate of lead has been put on the soil in spray¬ 
ing the trees. The quantity of arsenic and copper present is much 
greater than that in the virgin soil and the presence of the two, 
