14 
THE EXPERIMENTAL FIELD 
For this purpose, after a careful examination of many fields in 
the vicinity of Elliot, Ford county, by one of my assistants, Mr. E. O. 
G. Kelly, choice was made of twenty acres of dark rich loam, level 
and of a uniform quality, on the farm of Mr. James Jones, one and 
a half mile northeast of Elliot. 
This ground had been in corn the preceding year, and it was 
heavily infested by the corn-field ant. The old stalks were harrowed 
down and burned April 24 and 25, and the field was plowed to a depth 
of 4 to 6 inches April 26 to 28, with a gang of two plows, each cutting 
a furrow 15 inches wide. It was then twice harrowed with a toothed 
harrow — the last time May 7 — and was planted May 8 to 11, in rows 
80 rods long, 372 hills to the row, the hills 3^ feet apart each way. 
INSECT INFESTATION OF FIELD 
A number of ants' nests in this field, critically examined previous 
to April 26, all contained eggs and recently hatched young of the corn 
root-aphis. The degree of infestation of the field was ascertained by 
counting the nests of the corn-field ant overturned by the plow. 
Eleven hundred and forty-two nests were found in 62 furrows cross- 
ing the field and aggregating 15^ miles in length. This was at the 
rate of 74 ants' nests to the mile of furrow, 516 to tjie acre, or 10,320 
to the entire field. 
Nineteen days later 250 hills of the corn in the check plots of this 
field were found to harbor an average of 62 ants to the hill, — equiva- 
lent to nearly five millions in the entire field ; and within six weeks 
from the time of planting, the check hills averaged 162 root-lice, — 
equivalent to twelve and a half millions of those insects to the field. 
Even this statement does not fully describe the burden of infesta- 
tion with which our experimental field began the year. During his 
tramp of 15^ miles, backward and forward behind the plow, Mr. 
Kelly counted also 6519 white-grubs exposed in plowing, which is 
at the rate of nearly 3000 of these destructive insects to the acre, or 
59,000 for the entire field. Of course only a small part of the grubs 
in the soil were brought to view by the plowing, and this number 
may reasonably be trebled or quadrupled for an estimate of the whole 
number present. 
DESCKIPTION OF THE EXPERIMENT 
The ground being thus selected, found thus infested, and made 
ready for planting, an experiment was started May 9 with four 
principal substances — kerosene, oil of lemon, formalin, and carbolic 
acid — and with three others, to which less importance was attached — 
flowers of sulphur, chlorid of lime, and "Rex Dip." The experiment 
was laid out as follows : 
The first 50 rows from the east side of the field were planted with 
corn not treated, and available, consequently, as a check. The next 
24 rows were planted with seed treated with a 3 percent solution of 
