312 
Journal of Agricultural Research 
Vol. VIII, No. 8 
with the soil and being taken up in solution with the soil water normally 
absorbed by the roots. It is natural to suppose that some is absorbed in 
this way, and Headden's work convinces one that the arsenic thereby 
accumulated in the tissues of the tree in sufficient amounts may be readily 
determined by chemical analysis. Whether or not the trees are materially 
injured by arsenic absorbed in this way is a debatable question. 
To determine whether or not a visible injury can easily be brought 
about in this way, arsenic trioxid was added to the soil under three trees 
and sodium arsenite was added to the soil under three others. The 
chemicals were mixed with water in the proportion of i to 1,000 by weight. 
The sodium arsenite was completely dissolved before being applied. 
The chemicals were sprinkled on the surface of the ground with an 
ordinary watering pot. Repeated treatments were given, as shown in 
Table XI. The first application was made to a circular area of ground 
8 feet in diameter, with the tree in the center. The second was made in 
a ring 2 feet wide just outside the first treatment. Subsequent applica¬ 
tions alternated between these two areas of ground. 
No crop was grown in the orchard, and the ground was harrowed at 
frequent intervals but not plowed. The trees were irrigated by shallow 
furrows running about 4 feet from them. The precipitation during the 
experiment was as follows: 
1911. 
Inches. 
Inches. 
August. 
. 
November. 
September. 
.. I - 73 
December. 
. 65 
October. 
. 2.15 
1912. 
January. 
July. 
. i- 9 i 
February. 
. 39 
August. 
. **$3 
March. 
September. 
. 1.66 
April. 
. 3*59 
October. 
. 3*23 
May. 
. 2.66 
November. 
. 37 
June. 
December. 
. 74 
1913* 
January. 
March. 
February. 
. 47 
April. 
. 1*65 
No external symptoms of injury appeared in the aerial portion of any 
of the trees during the entire course of the experiment. The roots were 
not examined until the end of the experiment, for obvious reasons. Such 
injuries as were present in the roots at that time are recorded in Table XI. 
They were all strictly local, with no suggestion of ,a general or systemic 
poisoning. 
