12 BULLETIN 1316, U. S. DEPARTMENT OE AGRICULTURE 
performed to determine the extent to which arsenic applied to the 
tops of plants is carried to the roots. 
In the case of the barberry near Toledo, Ohio, reported in Table 
3, the distal roots were collected at a point about 4 feet distant from 
the crown and more than 2 feet beyond the point of application 
of the sodium-arsenite solution. The ground was level and sandy, 
and there was no indication from killed grass or otherwise that the 
solution had spread in the soil to that distance; yet arsenic was 
found in the roots, indicating that it might have been absorbed 
near the crown of the bush and transported within the roots toward 
their distal ends. 
Swingle and Morris (4-3) report that arsenic solutions applied to 
wounds in the limbs of apple trees were carried both up and down 
the limb. They state that " as a rule, it [the injury] extends farther 
upward than downward; but the reverse is sometimes true." The 
dead areas resulting from the entrance of the arsenicals in their tests 
frequently extended from 2 to 5 feet above the point of entrance 
and occasionally to a distance of 3 feet below. 
Many other workers have reported similar phenomena. In gen- 
eral, the transportation toward the top of the plant has been found 
greater and more rapid than in the reverse direction, and Bose (8) 
has concluded that the ascent of sap is eight times as rapid as the 
descent. 
A few experiments were performed by the writers in order to 
compare the action of sodium-arsenite solution applied to the roots 
and to the tops of plants. The plants used were small barberries, 
tomatoes, peppers, geraniums, cucumbers, and potatoes. Plate IV, 
Figure 1, illustrates the results with one series of tomatoes. In the 
first pot only 1 inch of the ends of the roots was dipped in 8-pound 
sodium-arsenite solution diluted 1 to 40. In the second pot the 
tip of the plant was dipped in the same solution for a period of three 
minutes, and in the third pot one leaf was dipped for the same 
length of time. 
In every case where a portion of the root was dipped, the entire 
plant began to wither within a few hours and eventually died, 
whereas in only a few cases did the injury from top dipping ex- 
tend beyond the portions actually dipped. It also was observed 
that when the tops were dipped plants with suberized leaves, such 
as the barberry, were injured less than plants with softer leaves. 
RATE OF LEACHING OF SODIUM ARSENITE FROM SOILS 
A fair-sized barberry bush growing in a wood lot in well-drained 
soil rich in leaf mold was treated with 2 gallons of a 1 to 40 dilution 
of 8-pound sodium arsenite on September 20, 1922. Samples of the 
surface soil from around this bush were collected on different dates 
and the quantities of arsenic present determined. The results are 
given in Table 5. The slight increase in the quantity of arsenic 
indicated on two different dates probably is due to irregularities 
in the distribution of the chemical and in the sampling. 
