Feb. 19,1917 Arsenical Injury through the Bark of Fruit Trees 
313 
Table} XI .—Results of treating the soil underneath apple trees with arsenical compounds 
to determine injury from absorption by roots 
Chemical. 
Amounts and dates of application. 
Arsenic trioxid.... 
.do. 
1911: Aug. 22 and Sept. 4,20 gm. 1912: 
June 18 and 20, July 2, 9, 16, and 30, 
20 gm.; Sept. 4,40gm.; Sept. 25 and 
Oct. 18, 80 gm. Total, 360 gm. 
1911: Aug. 22andSept. 4,2ogm. 1912: 
June 18 and 25, July 2, 9, 16, 30, and 
Sept. 4, 20 gm.; Sept. 25, 40 gm. 
Total, 220 gm. 
.do. 
.do. 
Sodium arsenite... 
1911: Aug. 22 and Sept. 4, 25 gm. 1912: 
June 18 and 25, July 2, 9, 16, and 30, 
25 gm.; Sept. 4, 50 gm.; Sept. 25 and 
Oct. 18, 100 gm. Total, 450 gm. 
.....do. 
1911: Aug. 22 and Sept. 4 ,25 gm. 1912: 
June 18 and 25, July 2, 9, 16, 30, and 
Sept. 4, 25 gm.; Sept. 25, 50 gm. 
Total, 275 gm. 
Same as No. 5, except that on Sept. 25 
only 25 gm. were used. Total, 250 
gm. 
.do. 
Injury. 
Two roots have outer bark slightly in¬ 
jured. A few rootlets killed. Leaves 
and branches uninjured. 
Leaves and branches uninjured. One 
root has outer bark injured. A few 
rootlets killed at the tips. 
Leaves and branches uninjured. A few 
rootlets killed. 
Leaves and branches uninjured. Three 
roots have outer bark covered in 
places with anastomosing spots that 
do not extend to the cambium. 
Many dead rootlets. 
Leaves and branches uninjured. Bark 
of roots slightly injured. Many root¬ 
lets killed. 
Leaves and branches uninjured. No 
injury to large roots and very little 
to rootlets. 
In the spring of 1913 it became necessary to remove the entire orchard 
block containing these trees, otherwise the applications to the soil would 
have been continued to date or until the trees had been severely injured. 
One conclusion is obvious, that considerable quantities of arsenic may 
be applied to an orchard soil relatively free from alkali without imme¬ 
diate harmful results. It should, perhaps, be added that the orchard 
in which this work was carried on is relatively free from alkali and that 
soils rich in certain alkali salts might keep more of the arsenical in 
solution. 
Too much significance must not be placed on the fact that a soluble 
compound (sodium arsenite) was applied to some of the trees, as we 
have no assurance that a large proportion was not rendered insoluble 
by the action of the soil. 
SYSTEMIC POISONING 
It is a noteworthy fact that the injuries described thus far in this 
paper were for the most part local. In fact, all were purely local 
except those that were a result of girdling limbs or trunks. 
It is a pertinent question whether or not trees can be made to suffer 
a general or systemic poisoning from arsenic, and still more pertinent 
whether or not such a poisoning ever occurs as a result of orchard spray¬ 
ing as now practiced by fruit growers. Headden has described certain 
symptoms which he suspects are due to systemic poisoning, but he 
does not regard the evidence as conclusive. 
Our own work on this subject has been meager and does not warrant 
very far reaching conclusions. It has been confined to two lines: (1) 
The treatment of the soil recorded in Table XI, and (2) observations on 
trees that have been treated with bandages on nearly every branch so 
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