14 BUIXETOf 1316. U. 5. DEPARTMENT OF AGRICULTURE 
arsenite solution. The solution was poured into the center of the 
crown and around the bottom of each bush, but not on the leaves or 
top. and none was spilled on the ground other than at the base. 
Stones, sticks, and sod were then piled around the bushes, effectively 
covering the treated ground. A number of young lambs were 
turned into this pasture a few days after the treatment and found 
one of the treated bushes. They gnawed the bark from the 
of some of the shoot? (PL IT. fig. 2), and several obtained suf- 
ficient arsenic to cause death. These shoots had been wet by the 
solution, and in drying sufficient arsenic had remained on the surface 
lice the fatal results. In this case, as in the previous one. no 
rain occurred between the time of treatment and the time the lambs 
gnawed the bushes. 
DISCUSSION 
A review of the literature on arsenic, primarily sodium arses 
in its relation to uses for weed killing, reveals the fact that arsenic 
has been extensivelv used for this purpose with good success and 
with no apparent permanent damage to the soil, which of neeessitv 
becomes the recipient of the substance. Soil organisms, such as 
bacteria, have been stimulated by small quantities of arsenic, and 
even higher plants grown on arsenic soils have shown stimulation, 
as manifested in increased growth. 
Incident to the use of arsenic, its extreme toxicity to animals had 
to be considered, and the literature cites numerous cases of poison- 
ing cattle, sheep, and horses from arsenic obtained from different 
sources, such as some smelter emanations and solutions used in w 
eradication. It has been discovered that cattle are attracted 
taste of arsenic. Repellents, such as aloes, have been used with 
success. These would eliminate the most undesirable feature in the 
use of arsenic. 
The experimental results presented in this bulletin give further 
information on some effects of arsenic when used for killing the 
common barberry. In preliminary greenhouse experiments it was 
found that the arsenious acid was the most toxic to the barberry. 
The sodium arsenites were less toxic, and of these the trisodium 
the least toxic. 
I ieid practice has shown that 2 gallons of a solution prepared 
from 1 gallon of commercial sodium arsenite containing the equiva- 
lent of S pounds of white arsenic and dilute 1 \ it! - parts of 
water were sufficient to cause the death of a single bush of the com- 
mon barberry. Killing was effected within three to seven days. 
Chemical analysis showed that the killed pla] Absorbed arsenic 
in nearly all parts, and the quantities in vegetative tissues varied 
from 0.007 to 0.1 SS per cent. Xumerous other plants, including 
grasses and trees, were tested, and all were killed by the solution 
specified, arsenic being found in their tissues. The poplar appeared 
very sensitive to arsenic poisoning and the wild cherry and oak the 
least susceptible. 
Spraying the aboveground portions of various plants with a solu- 
tion of arsenite identical with the one used for > application on the 
roots showed that only the treated portions were killed, and then 
only in the case of tender plants. Plants with waxy or leathery 
leaves were not affected when held in the solution for three minutes. 
