44 
Colorado Experiment Station 
ascertain whether trees which had never been sprayed take up arsenic. 
We have presented several cases in which the application of sodic 
arsenite to the soil, within the feeding area of the roots, was followed 
by the almost immediate taking up of the, arsenic and death of a por¬ 
tion or the whole of the tree. I have mentioned in all eight instances 
of this sort, one instance of an apple tree within a few feet of which 
the spray tank containing arsenate of lead was emptied followed by 
the death of one limb of the tree, and further the case of the elm tree 
has been given somewhat fully. It would seem that these cases would 
suffice, to prove that trees will take up enough arsenic from the soil 
to injure them, even when the arsenic has been applied in a dif¬ 
ficultly soluble form, as in the cases of one apple tree and that of 
the elm tree. To add to the force of these samples, I have examined 
peach trees which had not been sprayed but which were growing 
in land already rich in arsenic and these too contained arsenic though 
two of them were only five years old. The elm tree and the peach 
trees could not have gotten the arsenic except through the activity of 
the roots. If further proof is needed the presence of arsenic in the 
juices forced out of a fresh wound and in the leaves and fruit which 
had never received any spraying certainly indicate that'the arsenic 
is carried with the sap of the tree. It can certainly make no differ¬ 
ence whether the arsenic is originally in the soil or has been added, 
but the proofs are not wanting that this arsenic comes from the spray 
materials put upon the soil for it is associated in many cases with both 
lead and copper, as much as 0.003 P er cen f of lead having been found 
in one sample. These facts establish this, i. e., that the trees do take 
up arsenic from the soil together with lead and copper. 
One of the effects of the arsenic on these injured or partially 
killed trees is to stunt them. This is especially noticeable in those 
parts which we know to have been affected by sodic arsenite. 
Other causes for the unhealthy condition of these trees, their 
small size, the unnatural color of their bark, the early yellowing of the 
leaves, the small size and exceedingly high color of the fruit, have 
suggested themselves. Among these are insect injuries, atmospheric 
conditions, soils, etc. 
We can, I think, dismiss insect injuries, these having been care¬ 
fully watched for and guarded against, and also atmospheric agencies, 
including smoke, electricity, etc., and turn our attention to the soil 
conditions. The average depth of the soil is stated to be from three 
to three and one-half feet. I think that this is too high for the, 
whole aople orchard, but if the soil A two and one-half feet ^eep it is 
quite sufficient for the sustenance of healthy apole trees. There is, 
however, scarcely a healthy apple tree in the orchard or at most only 
a few of them. 
Whatever our views may be regarding the injurious properties of 
alkalis we cannot satisfactorily explain the, trouble on the theory that 
they are injuring the trees, for the total water soluble portion of the 
soil amounts only to 0.22 of one per cent, whereas we have healthy 
orchards in soil containing a much larger quantity of alkalis than this. 
