ARTIFICIAL INFECTION—-FIELD EXPERIMENTS. 41 
In the Metcalf field six piles of corn were laid. Two were well 
watered and two of the remaining four were covered over with rank 
weeds to increase the shade. The last two were not watered nor cov- 
ered with weeds. All were thoroughly infected throughout with 
Sporotrichum. Chinch bugs swarmed inside the piles and as long as 
the corn remained reasonably fresh they apparently made no effort 
to leave. 
A similar series of piles was constructed in the Botkins field, only 
they were larger, having 40 stalks to the pile. A dozen such heaps 
were made, and they were about 60 feet apart. None of the piles in 
the Botkins field was artificially infected. 
Four questions were to be decided by the corn-pile experiment: 
(1) Would the chinch bugs become diseased in an uninfected pile? 
(2) Would they become so in an artificially infected one? (8) Would 
the infected bugs leave the piles and carry the contagion to other 
parts of the field and ultimately bring on an epidemic? (4) Would 
the bugs die by sucking the juice of the corn, soured after cutting, as 
had been stated by certain farmers? 
The piles were prepared June 22. Heavy rains occurred June 25 
and 27, making the ground very muddy. Diseased bugs were noticed 
around the base of the corn in various parts of the field. The piles 
of cut corn were examined and a few dead bugs were found. The 
corn was very wet, and the lowest stalks and leaves in some of the 
piles were in mud. As the greater part of the leaves were still fresh, 
the bugs had not left the piles, but seemed quite as numerous as ever. 
If the juice had soured it had thus far caused no perceptible mor- 
tality among them. Molting had occurred to a considerable extent, 
and the old skins resembled dead bugs sufficiently to have probably 
caused some of the farmers to mistake them for bugs killed by sour 
juice or by Sporotrichum. The piles in the Botkins field, although 
‘untreated, contained more diseased bugs than the artificially infected 
ones in the Metcalf field. Conditions were probably more favorable 
in the former than in the latter case, since the corn was piled on 
higher ground and did not get so soggy. 
Thus far no effect worth mentioning from Sporotrichum was ob- 
served in any of the piles. The diseased bugs in the piles on the Bot- 
kins place served as infection for the other bugs. It seemed as 
though conditions in this field could not have been made better for 
the spread of infection, yet the number of diseased bugs was only a 
very small fraction of the living. 
On this date (June 27) a pile of freshly cut corn infested with 
bugs was made in each field, the one on the Metcalf place being in- 
fected artificially with Sporotrichum. All of the piles were ex- 
amined on July 6. The original ones (made June 23) were found 
