and aphids that protection from their injury had more than compen- 
sated for the original poor stand. It thus became our problem so to 
modify this treatment as to get the beneficial result without risk of 
the injury. 
It was evident enough that kerosene merely applied to the seed 
could act only by reason of its persistent odor — peculiarly offensive to 
ants — and it seemed qu'te probable that corn might be so treated with 
this or some other strong-smelling substance that ants would be kept 
out of the hills for a considerable time and that the seed would not be 
injured. As a test of substances possibly useful for this purpose, a 
long series of experimental plantings was made, from June to August, 
1905, and from February to July, 1906, in the field, at Urbana, and in 
the insectary connected with my office there, and a careful record was 
kept of the percentage of kernels germinating in each planting, and of 
the condition of the corn plants for several days after they appeared 
above ground. The substances thus tested as to their effects on corn 
were kerosene, kerosene emulsion, crude petroleum, turpentine, car- 
bolic acid, formalin, oil of lemon, oil of wantergreen, oil of cloves, oil 
of sassafras, wood alcohol, common alcohol, coal-tar. coal-tar water, 
carbon bisulphid, chlorid of lime, kainit, flowers of sulphur, lime, salt, 
various compound solutions of sulphur, lime, and salt, and of sulphur, 
lime, and blue vitriol, copper sulphate, iron sulphate, mustard, cam- 
phor, musk, lysol, tobacco-water, the proprietary insecticides known 
as "Scalecide," "Con Sol," "Calcothion," and "Fruitolin," and the so- 
called "Rex Dip." 
Plot Experiments, 1905 
For this purpose the use of a plot of ground was obtained in June, 
1905, on the farm of the Experiment Station at Urbana, on which the 
corn was planted in rows by hand, usually two grains to the hill. 
Fifteen thousand five hundred kernels were planted in this plot, 5750 
of them after treatment with kerosene, 2050 with kerosene emulsion, 
2000 with tar-water, 3650 with turpentine, and 2050, with no special 
application, serving as checks. The principal plantings were those 
made June 15, of 1500 kernels, and June 28, of 12,500 kernels. 
Smaller additional plantings, varying from 50 to 1000 kernels, were 
made June 29 and 30. July 18 and 21, and August 9. 
The results of the planting of June 15 were determined by an in- 
spection June 26, and those of June 28 were determined July 20 — the 
first, eleven days after planting and the second after twenty-two days. 
The weather of these two intervals differed' materially, that between 
June 15 and June 26 being rather dry, and that between June 28 and 
July 20 decidedly wet — a fact to be borne in mind at some points in 
comparing the two series of experiments. The ground must have been 
fairly moist, however, June 15, since a rain of 1.05 inches had fallen 
on the 10th, but the only rain to fall during the eleven days following 
June 15 was .06 of an inch on the 20th. Between the 28th of June 
and the 20th of July, on the other hand, rain fell on sixteen days, to 
