48 
distilled and re-distilled, and the forceps, knives, needles, slides and. 
cover glasses were all passed through the flame of an alcohol lamp 
just before being used. In order to assure myself that the bacteria 
observed came “actually from the interior of the bugs, I carefully 
washed several examples with a camel’s-hair brush in a drop of 
water upon the slide, but could find no bacteria in the fluid used. 
By crushing the same specimens and treating them as before, the 
bacteria appeared in the usual numbers. It then occurred to me 
that it was possible that the corn itself upon which these bugs were 
feeding was in a diseased condition, and that the bacteria were 
derived from its juices. | consequently took portions of the pith of 
several stalks, crushed them upon the slide, and examined the sap 
with high powers of the microscope. I found, of course, a multitude 
of minute particles of various kinds and variously aggregated. 
Most of them were agitated by the Brownian movement, but none 
of them were recognizable as bacteria. These observations were 
several times repeated, and I finally stained and mounted some of 
the solid particles from the sap for more careful study under high 
powers. On the 9th of August I made a visit to Champaign, and 
went over the subject with Prof. T. J. Burrill, of the Industrial: 
University there, well known as an authority on everything relating 
to bacteria. An abundance of the organisms already mentioned were 
found in the fluids of chinch-bugs examined, but nothing new was 
discovered. We also determined positively the absence of any 
similar organisms in the juices of the corn. 
On the 10th of August I found that chinch-bugs in the pupa 
stage obtained at Champaign were swarming with the same bacteria 
as those observed at Normal. 
In order to determine the extent to which these micro-organisms 
prevailed among other insects, I crushed plant-lice from melon vines 
and from corn, beetles from various situations, and other. insects, 
but failed to find anything resembling the bacteria of the chinch- 
bug. Next, wishing to ascertain whether chinch-bugs of different 
ages and stages of development differed with respect to the abund- 
ance of these parasites, (for so I began to consider them), I exam- 
ined on the 11th a number of specimens from Champaign which 
had but just passeca the first molt. Bacteria were present, but in 
much smaller numbers than in pup obtained at the same time and 
place. This tallied entirely with previous observations, which had 
led me to conelude that they were fewer in young bugs than in old. 
In order still further to test the possibility of their being derived 
in some way from the food of the insects, I next examined a num- 
ber of specimens which had been confined in a bottle for several 
days, until they were nearly or quite starved. A specimen which 
had just passed the second molt, and was dead, but still fresh and 
plump, contained the bacteria in immense numbers, many of them 
ageregated in clusters hke the zodgloea masses of Micrococcus. Other 
_ live specimens from the same lot also contained ereat numbers of. 
them. All the observations made upon this point tended to estab- 
lish the inference that the micro-organisms were entirely independent 
of the food ingested,—a fact which placed them definitely in the 
category of parasites. On the 14th of August, again I found them 
very abundant, and showing by their connection in strings that they 
