42 
Colorado Experiment Station 
Systemic Arsenical Poisoning. 
What I have said concerning the action of arsenic and lime might 
properly, perhaps, have been put under this head, but I have chosen 
to. treat it by itself because it is so pronounced a feature that it is not 
possible to overlook it and it will be more easily recognized by those 
familiar with it than if it were included under this caption. 
While there is no single feature in the cases of the trees remaining 
to be described which may be taken, as the destroyed bark of the 
crowns and roots in the first, or the deposition of an incrustation on 
the surface of the wounds or on the bark in the se,cond case, as guiding 
features, we have some which force themselves on our attention, 
one is a reddish yellow color of the bark, especially of the limbs, an¬ 
other is the lack of thriftiness. The former is not, in my opinion, 
specifically diagnostic of arsenical poisoning but rather of malnutri¬ 
tion, itself a result possibly of the arsenic. 
I have seen this color in an orchard which I am convinced is 
suffering more from other causes than from arsenic, though it may 
have contributed some in bringing about the bad condition of the 
orchard. As I shall not refer to this orchard again, I may describe 
briefly some of its more marked features. This orchard, in the 
spring of the year, is a very marked feature of that section of the 
country because of its abnormal color. There are but few or no signs 
of corrosion. A large number of these trees were pulled up in the 
late winter and spring of 1909. The ends of one half of the roots, 
this is the estimate of the man who pulled them up and not mine, 
were found to be rotted off. Some of the remaining trees were pul¬ 
led up and a few of the roots were found to be in this condition. 
It is my opinion that the color of this orchard is mostly due to starvation 
but this forms a part of another study, and is mentioned to dissipate 
any idea that some might get that this, reddish color is diagnostic 
of arsenical poisoning. This color is not due to sunburning. I have 
considered this, but there are some facts very hard to explain on this 
theory, for instance this color is only a little more intense on the 
south side of the limb than on the north side and all of the trees of an 
orchard mav show this color. 
^ 7 
Almost any tree in some of these orchards might be vred as an 
example to illustrate and introduce the discussion of systemic arsenical 
poisoning. . 
I have stated that the subject of the action of lime and arsenic 
might have been included under this caption and the first example 
is a Jonathan; the tree is small for its age, about 14 years old, the 
bark is somewhat yellowish and it represents a case of moderate 
bleeding. The deposit formed is rich in arsenic. I cut ^ff a limb 
of the tree; the interior portion of it was strongly discolored, the dis¬ 
coloration was not confined to the annual rings. An examination 
of this wood showed the presence of arsenic. Both of the preced¬ 
ing tests were repeated with a confirmation of the results. The 
crown of this tree is not corroded. We evidently have in this case 
