21 
ArsenicaIv Poisoning oe Fruit Trees. 
only incidental but in the case of our trees, I believe it to be a very 
suspicious condition. 
I have now given the reasons for my conviction that the ar¬ 
senic which has accumulated in our soil from the use of arsenical 
sprays used in combatting the codling moth and other fruit, leaf and 
bark eating insects is the cause of this trouble. To restate them suc¬ 
cinctly, we'find the arsenic already accumulated in’the soil to amextent 
far beyond the danger line for solutions as established by competent ex¬ 
perimenters. We find it also in the tissues of the plant where it is not 
normally present; we have proven both in the case of herbaceous and 
woody plants that soluble arsenical compounds will cause their death. 
I regret that I can see no other conclusion than that the cor¬ 
roding of the crowns, the killing of the bark, the staining and final 
destruction of the woody fiber, the early dropping of the leaves 
presaging the early death of the tree and its final death a few 
months later are caused by arsenical poisoning. 
soeuble arsenic is present in the soil. 
In preceding paragraphs, I have made two statements which 
will help us to explain but in no wise to remedy the trouble. One 
statement is that the only protection against arsenical poisoning of 
our orchard trees is the insolubility of the arsenical preparations 
used in spraying and that their continued immunity from poison¬ 
ing requires that these arsenical compounds shall not be rendered 
soluble by any agent in the soil. Again, also in an introductory 
paragraph, I state that from the standpoint of my own depart¬ 
ment, this subject was really approached through the study of the 
effects of the alkalies. 
It is certainly true that it is possible that in time, these arseni¬ 
cal compounds might accumulate in the soil to a sufficient extent 
to enable the feeding roots of the tree to bring enough arsenic into 
solution to be dangerous to the life of the tree by systemic poison¬ 
ing. It is useless, however, to dwell upon this possibility when there 
are known conditions, amply sufficient to explain all the facts. Our 
soils, especially near the surface, contain from 0.20 of one per cent 
to upwards of one per cent of alkalies, from 8,000 pounds to up¬ 
wards of 40,000 pounds of alkalies in an acre foot. A few small 
areas may be practically free from these salts, but the rule is that 
they are present. It may be accepted as essentially correct that 
these salts consist of sodic sulfate and sodic chlorid. There is al¬ 
most always a small amount of sodic carbonate present, but it is 
sometimes absent, as is the case in one of the soils in question. 
alkalies render arsenic soluble. 
These so-called alkali salts, sodic-sulphate, carbonate and 
chloride or to call them by their more common names, Glauber’s 
Salt, Sal Soda, and ordinary kitchen salt, are capable of bringing 
