Pot Experiments, 1906 
In all the experiments of 1906, Learning seed-corn of excellent 
quality was planted, at a depth of an inch, in good black soil contained 
in ordinary earthen flower-pots seven inches across, and kept in the 
insectary of my ofiice building at Urbana. Temperature and moisture 
conditions, being under strict control, were made as nearly those of 
a normal spring as possible. Thirty-five check lots of 50 kernels each 
(1750 kernels in all) were planted with untreated seed in the course of 
these experiments. Sixteen hundred and eighty of these kernels ger- 
minated, and this germination ratio (96 percent) may be used for com- 
parison in determining the effect of our various applications to the 
seed. 
Kerosene. — Kerosene was used in two ways in these experiments : 
(1) by mixing it thoroly with the seed in quantities varying from }i 
of a fluid ounce to 3j^ ounces for each gallon of corn; and (2) by 
putting the seed into kerosene and soaking it there, previous to plant- 
ing, for periods varying from 10 minutes to 19 hours. The main 
results of these various experiments were as follows : 
Of 800 kernels planted after stirring in kerosene thoroly, at rates 
varying from % of an ounce to 2 ounces for each gallon of corn, 98 
percent germinated, and only 2 of the plants showed any trace of 
injury. Fifty kernels of this lot, treated at the rate of 2 ounces of 
kerosene to the gallon, all sprouted, and none of these plants were in- 
jured. Furthermore, of 200 kernels treated with kerosene at the rate 
of 23/3 to 3^ ounces to the gallon of corn, 92 percent germinated, 
and only 3 plants gave any appearance of injury. It would naturally 
be inferred from this experiment that at least an ounce (two table- 
spoonfuls) of kerosene to the gallon of corn might be safely used 
under conditions as favorable as those in our management, but we 
shall later find evidence, in the outcome of a field experiment made 
the following spring, that only half this amount injured corn slightly, 
but still appreciably, under the weather conditions of 1906. 
Soaking the corn in kerosene for 10- to 20- minute periods, 200 
kernels in each experiment, gave a germination ratio of 88 percent for 
the first and 93 percent for the second, but with the appearance of 
injury to 77 percent of the plants in the 10-minute lot and of 80 per- 
cent in the 20-minute lot. Furthermore, the plants which grew, aver- 
aged only 2% inches high fifteen days after planting, while 100 plants 
from untreated seed averaged 6^ inches. The corn would perhaps 
have outgrown this backset, and might have made a crop, if planted 
out-of-doors, better than the average in the field, provided that the 
latter was injuriously infested by the corn root-aphis. 
Soaking seed in kerosene for periods varying from 4 hours to 19 
hours gave variable results, as reported by Mr. Kelly. Only 1 out 
of 50 grains (2 percent) soaked for 4 hours had sprouted at the end 
of thirteen days, while 164 kernels out of 200 (82 percent) which had 
been soaked for 16 hours before planting, appeared above ground 
