51 
moderate numbers. At this time, however, no especial difference 
could be detected related to a difference of situation, while in torpid 
specimens the bacteria were apparently no more abundant than in 
those more active. On the 27th of the month, four bugs were 
examined from Gonner’s field, and two from one ‘of the others, but 
no bacteria whatever were found in any of them. These bugs were 
taken from the husks of the corn. They were in a sluggish condi- 
tion, and apparently had ceased to feed. 
Believing that I had now obtained as definite proof as was possi- 
ble by this method that the bacteria observed were the cause of 
the remarkable diminution of the bugs in one of these fields, I next 
attempted the artificial cultivation of the microphytes, with a view 
to getting them free from mixture with other substances, for more 
careful and convenient study. 
I also wished to see whether the exposure Net healthy chinch- bugs 
to fluids containing the bacteria would have any effect upon the 
insects; and, if it would, whether those so affected would themselves 
convey the contagion to others. 
A number of culture tubes were made, similar in character to 
those ordinarily used for the pure cultivation of microphytes, and 
filled with hot infusions of corn and beef, made by boiling the pith 
of cornstalks and small pieces of beef in a test-tube for fifteen or 
twenty minutes. Some of these were carefully infected in the usual 
manner with fluids from crushed chinch-bugs, while others were left 
free. That containing the corn infusion produced only Bacterium 
termo and Bacillus subtilis. The bacteria from the insects developed 
only in the infected tube containing the beef infusion. In this tube 
myriads of these bacteria occurred, both in zodglaa masses and as 
separate individuals, but no other micro-organisms appeared. In 
one of the fields which had been worst attacked by chinch-bugs, the 
leaves were dead as high as the ears. Here it was noticed that the 
sheath of the leaf was often gummed to the stalk by a thick exu- 
dation, like half-dried glue. A few dead adults were noticed here, 
imbedded in mold, but of a different kind from that seen at Jack- 
sonville. When portions of this exudation were moistened and 
studied under the microscope, the fluid was found thick with bac- 
teria, indistinguishable from those occurring in the bodies of the 
insects, and the same were thickly scattered through the translucent 
masses of viscid jelly. The inference was plain that they were de- 
rived from the excrement of the chinch-bug, in which they had 
continued to develop. 
