lo The Colorado Experiment Station. 
this seems to be the case. A branch from a neglected tree in my 
garden is white throughout •( Plate IV., Fig. 4). The age of this 
tree is not less than 15 years, and has to my knowledge been sub¬ 
jected to temperatures ranging as low as -40 degrees F., and often 
below -18 degrees F. I do not know the early history of this tree, 
and do not wish to give more weight to the fact mentioned than is 
due. I have not examined pear trees as carefully as I have apple 
trees, but the few branches that I have observed were not dis¬ 
colored in this manner. Plate IV., Fig. 3 represents a section of the 
trunk of a pear tree, killed by arsenic, and shows the manner in 
v/hich the wood is stained. 
Another effect of this trouble is to cause the bark to split and 
the wound to bleed. (Plate V., Figs, i and 2). This result may 
be partly and possibly wholly induced by another cause. Mr. 
Whipple suggests that the splitting open of the bark may result 
from the girdling, but this will certainly not apply in many cases, 
though it may in some. I have in mind two orchards in which this 
cracking and bleeding occurs to such an extent that any. person 
whether he were accustomed to orcharding or not would take notice 
of it. One of these orchards is today rated as a very fine one. 
With these general statements concerning the manifestations 
of the difficulty, I will give the facts on which the statement 
rests, that the arsenic is not only in the soil but has been absorbed 
by the trees. 
I have taken samples from fourteen trees, eleven apple and 
three pear trees. These samples consist of roots, stumps, one trunk 
and branches. I should add to the above two samples of the de¬ 
posit formed by the bleeding referred to in a preceding paragraph. 
On these various samples, thirty tests for arsenic were made and its 
presence was established in every instance. I did not attempt to 
make quantitative determinations except in a few cases which 
showed from 1.25 parts to 12.77 parts of arsenic per million of the 
woody tissue. I found the reaction for arsenic stronger in the roots 
and crown of the trees than in the branches, but could not witli 
certainty distinguish any difference in the amount of arsenic present 
in the green or natural colored portion of the limb and the discolored 
portion. 
I do not wish to weary the general reader with technical details, 
but it is proper that he be assured that the arsenic reported as hav¬ 
ing been found in these thirty different samples, was not contained 
in any or all of the reagents used. The proof of this was obtained 
by using a piece of oak wood and carrying it through as though 
it were a sample of an apple tree when a negative result was ob¬ 
tained showing that both the wood and the reagents were free from 
arsenic. This was not the only precaution, for four blank tests were 
made during the work to make sure that no error should arise from 
