2 BULLETIN 1027, U. S. DEPARTMENT OF AGRICULTURE. 
ravages of the Colorado potato beetle. In 1872 Le Baron (70) sug- 
gested the application of Paris green to fruit trees to combat the 
spring cankerworm, but Lodeman (75) states that only a few of the 
most progressive orchardists adopted arsenical spraying against 
the codling moth until after the establishment of the State agri- 
cultural experiment stations resulting from the passage of the Hatch 
Act in 1887. 
The question soon arose as to the possible danger to the consumer 
from the use of potatoes the vines of which had been treated with 
a poisonous compound, such as Paris green. One of the first in- 
vestigators of this subject, Kedzie, in 1872 (64) and 1875 (65), con- 
cluded "that there is but very little danger of the potato tuber 
being poisoned so as to endanger the health of the consumer. Ar- 
senic is equally deleterious to the vegetable as well as the animal 
system. If added in dangerous quantity to the plant, the plant 
dies, no potatoes are formed." McMurtrie (78) detected no arsenic 
in potatoes which had been subjected to applications of Paris green. 
Lodeman (75) states that London purple was recommended as 
an insecticide in 1877. Cook (26), who sprayed apple trees on 
May 25 and June 20, 1880, at the rate of 1 pound of London purple 
to 100 gallons of water, reported that 100 blossom ends cut from the 
sprayed trees on August 19 showed no trace of arsenic. -He proved 
also (27) that it took but a very small amount of the arsenites to 
kill potato beetles, currant slugs, and cabbage caterpillars, and 
discovered that the poison was retained on plants sheltered from 
rain for 10 to 20 days. He concluded that it was safe to use Paris 
green or London purple on trees the fruit from which would not be 
eaten for four or five weeks after the application. 
Wheeler (132) , in 1888, reported that it was safe in California, where 
rainless summers prevail, to spray vines with Paris green. When the 
vines were sprayed with 1 pound of Paris green to 16 gallons of water, 
"ten times as strong as the solution recommended for general use," 
Rising (114), the State analyst, found only traces of arsenic on the 
grapes and none in the wine made therefrom. 
Objection was offered to the use of arsenicals, on the ground that 
they frequently caused more or less injury to the foliage. Gillette 
(58), however, found that "lime added to London purple or Paris 
green in water greatly lessens the injury that these poisons would 
otherwise do to foliage." Weed (129) recommended applying 
insecticides and fungicides together, and Gillette (58) showed that 
London purple can be used at least eight or ten times as strong 
without injury to foliage if applied in common Bordeaux mixture 
instead of in water. Gillette (59) stated, in 1891, that a mixture of 1 
ounce of Paris green to 100 ounces of flour was the most effectual 
