22 
crop was virtually destroyed. In a plot of 2000 hills were 2467 stalks, 
of which 95 percent were less than 4 feet high, and 75 percent were 
20 inches high or less. In this entire plot were only 95 ears — a num- 
ber equivalent to 169 ears to the acre — and these were mainly nubbins. 
Eleven hundred and thirty-eight h'lls contained still living plants, and 
in 1093 of them the root-aphis was still present. Four hundred and 
sixteen hills which were either dead or withered, dry, and barely 
living, all contained the root-aphis at the time, or showed by the bur- 
rows of ants along the roots that they had been previously infested. 
In a ne-'ghboring field practically uninfested, with which this is to be 
compared, 2000 hills contained 4324 well-grown stalks with 4024 ears, 
only 201 of which were nubbins. 
More Experiments necessary 
Our field experiment of 1906, decisive as it seems, is, of course, 
to be taken as applying exactly only to similar, if not identical, con- 
ditions — a similar soil similarly prepared, equally infested with the 
corn root-aphis, and subject to similar weather conditions — and with 
a treatment of seed identical with ours in all particulars, including 
materials of the same quality and strength. How far the results 
here described may be expected to apply to a dififerent soil, less 
heavily, or even much more heavily, infested, more thoroly prepared, 
and planted during either a very wet spring or a very dry one, with 
a less perfect seed, treated with slightly different chemicals and com- 
pounds, can be learned only by repeated and varied experiment. In- 
deed, the possibilities of useful experiment with this method are almost 
innumerable, and can scarcely be exhausted by any one office, however 
well manned and equipped, and however long its program of opera- 
tions. The procedure is so simple and so inexpensive, however, that 
any careful corn grower can test it, and its usefulness in ordinary 
pract'ce must be finally determined by such general, careful, and oft- 
repeated trial as farmers themselves may think it worth while to 
make. It is my purpose to test it by similar operations in several 
successive years, the results of which will be reported in later articles 
of this series, and '"t w'll greatly help us to an early practical conclu- 
sion if others interested will experiment carefully, and report upon 
their methods, materials, and results. 
An Additional, Minor Test 
Further special tests on the reactions of ants to the various re- 
pellents of our list were made by planting, close around burrows of 
these ants in the field', a few hills of corn, one of wh'ch was left un- 
treated as a check, the remainder being treated with one of the repel- 
lents as a test. "Rex D'p," formalin, carbolic acid, oil of lemon, kero- 
sene, chlorid of lime, sulphur, and common lime were tested in this 
way. The hills so planted were thus immediately exposed to infesta- 
tion, and any failure of the ants to occupy them would be particularly 
significant. The test plantings were all made by Mr. Kelly April 5, 
